Luminosity and Chromaticity: On Light and Color

Luminosity and Chromaticity: On Light and Color

Key Terms and Ideas

  • Luminosity and Chromaticity
  • Light and Color
  • Diwali (Festival of Light) and Holi (Festival of Colors)
  • Rama and Krishna
  • Non Dual Vedanta and Trika Philosophy
  • 1 and 3
  • Verticalism and Horizontalism
  • Vedic and Tantric
  • Flute of Krishna and Shiva Jyotir Linga
  • Bow and Arrow of Ram
  • Ram Parivar and Shiv Parivar
  • Shiv Ratri
  • Plato and Aristotle
  • Sun, Moon, Earth and Mars
  • Rods and Cones in Retina
  • Color Temperature
  • Lok and Kosh
  • Seven Chakra
  • Trishool
  • Ram, Lakshman, Sita, Hanuman
  • Achromatic and Chromatic
  • Grey scale and Color Primaries
  • Mind and Moon
  • Moon and Emotions
  • Tone Circle
  • Color Circle
  • Pythagoras
  • 3 and 7
  • 137
  • 007
  • Prism
  • Seven Colors
  • 4 + 3 = 7
  • 4 x 3 = 12
  • Pentatonic
  • Heptatonic
  • Diatonic Scale
  • Chromatic Scale

Newton’s Color Circle

Source: http://winlab.rutgers.edu/~trappe/Courses/ImageVideoS06/MollonColorScience.pdf

Color Circle in Opticks of I.Newton

Source: Reprint of Opticks by Project Gutenberg

Color Sensation

Source: Understanding color & the in-camera image processing pipeline for computer vision

Electromagnetic Spectrum

Source: Notes for the course of Color Digital Image Processing

Color Temperature

Source: Understanding color & the in-camera image processing pipeline for computer vision

Color Temperatures of the Stars

Luminosity Function

Source: Understanding color & the in-camera image processing pipeline for computer vision

CIE 1931 XYZ

Source: Understanding color & the in-camera image processing pipeline for computer vision

Luminance

Source: Human Vision and Color

Brightness, Lightness,Hue, Saturation, and Luminosity

Source: The Brightness of Colour

Brightness has been defined as the perceived intensity of a visual stimulus, irrespective of its source. Lightness, on the other hand, is defined as the apparent brightness of an object relative to the object’s reflectance. Thus increasing the intensity of light falling on an object will increase its apparent brightness but not necessarily its apparent lightness, other things being equal [1]. Saturation is a measure of the spectral ‘‘purity’’ of a colour, and thus how different it is from a neutral, achromatic stimulus. Hue is the perception of how similar a stimulus is to red, green, blue etc. Luminous efficiency, or luminosity, measures the effect that light of different wavelengths has on the human visual system. It is a function of wavelength, usually written as V(l) [2], and is typically measured by rapidly alternating a pair of stimuli falling on the same area of the retina; the subject alters the physical radiance of one stimulus until the apparent flickering is minimised. Thus luminance is a measure of the intensity of a stimulus given the sensitivity of the human visual system, and so is integrated over wavelength [3]. Luminance is thought to be used by the brain to process motion, form and texture [4].

Clearly, brightness is monotonically related to luminance in the simplest case: the more luminant the stimulus is, the brighter it appears to be. However, the Helmholtz-Kohlrausch (HK) effect shows that the brightness of a stimulus is not a simple representation of luminance, since the brightness of equally luminant stimuli changes with their relative saturation (i.e. strongly coloured stimuli appear brighter than grey stimuli), and with shifts in the spectral distribution of the stimulus (e.g. ‘blues’ and ‘reds’ appear brighter than ‘greens’ and ‘yellows’ at equiluminance) [1; 5–6].

The HK effect has been measured in a variety of psychophysical studies [7–8] and is often expressed in terms of the (variable) ratio between brightness and luminance. 

Chromaticity

Source: Human Vision and Color

Human Eye

Source: Human Vision and Color

Human Retina

Source: Human Vision and Color

Rods and Cones Photoreceptors

Source: Human Vision and Color

Color Receptors

Source: Human Vision and Color

Tristimulus Color

Source: Color/CMU

Visual Sensitivity

Source: Human Vision https://people.cs.umass.edu/~elm/Teaching/ppt/691a/CV%20UNIT%20Light/691A_UNIT_Light_1.ppt.pdf

Light and Color (Photometry and Colorimetry) I

Source: Interactive Computer Graphics/UOMichigan

Light and Color (Photometry and Colorimetry) II

Source: Interactive Computer Graphics/UOMichigan

Two Types of Light Sensitive Cells

Source: Interactive Computer Graphics/UOMichigan

Cones and Rod Sensitivity

Source: Interactive Computer Graphics/UOMichigan

Distribution of Cones in Retina

Source: DIVERSE CELL TYPES, CIRCUITS, AND MECHANISMS FOR COLOR VISION IN THE VERTEBRATE RETINA

Types of Color Stimuli

Source: Perceiving Color. https://www.ics.uci.edu/~majumder/vispercep/chap5notes.pdf

Color Perception

Source: Perceiving Color. https://www.ics.uci.edu/~majumder/vispercep/chap5notes.pdf

CIE XYZ Model

Source: Human Vision and Color

Luminance and Chromaticity Space

Source: Understanding color & the in-camera image processing pipeline for computer vision

1931 CIE Chromaticity Chart

CIE 1931 Chromaticity Diagram

Source: Human Vision and Color

Source: Notes for the course of Color Digital Image Processing

Additive Colors

Source: Human Vision and Color

Subtractive Colors

Source: Human Vision and Color

Color Mixing

Source: Human Vision and Color

Color Appearance Models
  • RGB
  • CMY
  • CIE XYZ
  • CIE xyY
  • CIE LAB
  • Hunter LAB
  • CIE LUV
  • CIE LCH
  • HSB
  • HSV
  • HSL
  • HSI
  • YIQ for NTSC TVs in USA
  • YUV for PAL TVs in EU
  • YCbCr for digital TVs
  • Munsell Color System

Color Models are device independent. For discussion of device dependent color spaces, please see my post Digital Color and Imaging.

LMS, RGB, and CIE XYZ Color Spaces

Source: Color/CMU

HSV Color Space

My Related Posts

Reflective Display Technology: Using Pigments and Structural Colors

Color Science and Technology in LCD and LED Displays

Color Science of Gem Stones

Nature’s Fantastical Palette: Color From Structure

Optics of Metallic and Pearlescent Colors

Color Change: In Biology and Smart Pigments Technology

Color and Imaging in Digital Video and Cinema

Digital Color and Imaging

On Luminescence: Fluorescence, Phosphorescence, and Bioluminescence

On Light, Vision, Appearance, Color and Imaging

Understanding Rasa: Yoga of Nine Emotions

Shapes and Patterns in Nature

Key Sources of Research

What Are The Characteristics Of Color?

https://www.pantone.com/articles/color-fundamentals/what-are-the-characteristics-of-color

Birren Color Theory

by ADMIN on MARCH 11, 2012

http://www.wonderfulcolors.org/blog/birren-color-theory/

Light, Color, Perception, and Color Space Theory

Professor Brian A. Barsky

barsky@cs.berkeley.edu

Computer Science Division
Department of Electrical Engineering and Computer Sciences University of California, Berkeley

Understanding Color Spaces and Color Space Conversion

https://www.mathworks.com/help/images/understanding-color-spaces-and-color-space-conversion.html

The Human Visual System and Color Models

Click to access Carmody_Visual&ColorModels.pdf

Defining and Communicating Color: The CIELAB System

Color Vision and Arts

http://www.webexhibits.org/colorart/index.html

PRECISE COLOR COMMUNICATION: COLOR CONTROL FROM PERCEPTION TO INSTRUMENTATION

KonicaMinolta

A short history of color theory

https://programmingdesignsystems.com/color/a-short-history-of-color-theory/index.html

Let’s Colormath

Understanding the formulas of color conversion

https://donatbalipapp.medium.com/colours-maths-90346fb5abda

A History of Human Color Vision—from Newton to Maxwell

Barry R. Masters

Optics and Photonics January 2011

https://www.osa-opn.org/home/articles/volume_22/issue_1/features/a_history_of_human_color_vision—from_newton_to_max/

The Difference Between Chroma and Saturation

Munsell Color

Charles S. Peirce’s Phenomenology: Analysis and Consciousness

By Richard Kenneth Atkins

The Evolution of Human Color Vision/ Jeremy Nathans

Jeremy Nathans Lecture on Color Vision

JEREMY NATHANS LECTURE ON COLOR VISION

JEREMY NATHANS LECTURE ON COLOR VISION

JEREMY NATHANS LECTURE ON COLOR VISION

The Genes for Color Vision

Jeremy Nathans

SCIENTIFIC AMERICAN FEBRUARY 1989

A Short History of Color Photography

Photography  |  Angie Kordic

https://www.widewalls.ch/magazine/color-photography

Blue: The History of a Color (2001)

followed by Black: The History of a Color (2009) and then Green: The History of a Color (2014), all produced by the same publisher. A fifth, devoted to yellow, should come next. 

Historic Look on Color Theory 

Steele R. Stokley

The evolution of colour in design from the 1950s to today

Francesca Valan

Journal of the International Colour Association (2012): 8, 55-60

Greek Color Theory and the Four Elements

J.L. Benson

University of Massachusetts Amherst

A SHORT HISTORY OF COLOUR PHOTOGRAPHY

https://blog.scienceandmediamuseum.org.uk/a-short-history-of-colour-photography/

History of Color System

The Origins of Modern Color Science

J D Mollon

Click to access MollonColorScience.pdf

The History of Colors

Tobias Kiefer

Click to access Assignment_History_of_Colors.PDF

Notes for the course of Color Digital Image Processing

Edoardo Provenzi

Understanding color & the in-camera image processing pipeline for computer vision

Dr. Michael S. Brown

Canada Research Chair Professor York University – Toronto

ICCV 2019 Tutorial – Seoul, Korea

Chapter 2
Basic Color Theory

Click to access t3.pdf

Color Science

CS 4620 Lecture 26

Click to access 26color.pdf

Color Image Perception, Representation and Contrast Enhancement

Yao Wang
Tandon School of Engineering, New York University

A GUIDE TO LIGHT AND COLOUR DEMONSTRATIONS

Arne Valberg, Bjørg Helene Andorsen, Kine Angelo, Barbara Szybinska Matusiak and Claudia Moscoso

Norwegian University of Science and Technology Trondheim, Norway

https://www.ntnu.edu/documents/1272527942/1272817015/2015-09-08+DEMO+web.pdf/f1695ca5-b834-4d05-a011-a185f6562e32

A Primer to Colors in Digital Design

Archit Jha

Jul 16, 2017

https://uxdesign.cc/a-primer-to-colors-in-digital-design-7d16bb33399e

Chapter 7 ADDITIVE COLOR MIXING

Click to access 07_additive-color.pdf

Computergrafik

Matthias Zwicker Universität Bern Herbst 2016

Color

Click to access ColorPerception.pdf

Introduction to Computer Vision

The Perception of Color

In: Webvision: The Organization of the Retina and Visual System [Internet]. Salt Lake City (UT): University of Utah Health Sciences Center; 1995–.2005 May 1 [updated 2007 Jul 9]

https://pubmed.ncbi.nlm.nih.gov/21413396/

Visual Pigment Gene Structure and Expression in Human Retinae 

Tomohiko Yamaguchi,  Arno G. Motulsky,  Samir S. Deeb

Human Molecular Genetics, Volume 6, Issue 7, July 1997, Pages 981–990, https://doi.org/10.1093/hmg/6.7.981

https://academic.oup.com/hmg/article/6/7/981/572151

The Difference Between Chroma and Saturation

LUMINANCE AND CHROMATICITY

https://colorusage.arc.nasa.gov/lum_and_chrom.php

Number by Colors

A Guide to Using Color to Understand Technical Data
  • Brand Fortner
  • Theodore E. Meyer

Chapter 5 Perceiving Color

The Practical Guide To Color Theory For Photographers

History of the Bauhaus

https://bauhaus.netlify.app/form_color/color/

The Digital Artist’s Complete Guide To Mastering Color Theory

byLeigh G

BASIC COLOR THEORY

Anthony Holdsworth

Molecular Genetics of Color Vision and Color Vision Defects

Maureen Neitz, PhDJay Neitz, PhD

Arch Ophthalmol. 2000;118(5):691-700. doi:10.1001/archopht.118.5.691

https://jamanetwork.com/journals/jamaophthalmology/fullarticle/413200

Color Theory: Introduction to Color Theory and the Color Wheel

https://blog.thepapermillstore.com/color-theory-introduction-color-wheel/

Color Spaces and Color Temperature

https://tigoe.github.io/LightProjects/color-spaces-color-temp.html

The Brightness of Colour

David Corney1, John-Dylan Haynes2, Geraint Rees3,4, R. Beau Lotto1*

EECS 487: Interactive Computer Graphics

Colorimetry

KonicaMinolta

Basics of Color Theory

THE BASICS OF COLOR PERCEPTION AND MEASUREMENT

Hunterlab

https://www.hunterlab.com/color-measurement-learning/glossary/

Color Matching and Color Discrimination

The Science of Color

2003

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.457.9467&rep=rep1&type=pdf

1.3 Color Temperature

https://www.mat.univie.ac.at/~kriegl/Skripten/CG/CG.html

https://www.mat.univie.ac.at/~kriegl/Skripten/CG/node10.html

Color Spaces and Color Temperature

https://tigoe.github.io/LightProjects/color-spaces-color-temp.html

Digital Camera Sensor Colorimetry

Douglas A. Kerr

Click to access Sensor_Colorimetry.pdf

Chromatic luminance, colorimetric purity, and optimal aperture‐color stimuli

DOI: 10.1002/col.20356

https://www.researchgate.net/publication/230164581_Chromatic_luminance_colorimetric_purity_and_optimal_aperture-color_stimuli

Title: A Review of RGB Color Spaces …from xyY to R’G’B’

The CIE XYZ and xyY Color Spaces

Douglas A. Kerr

Click to access CIE_XYZ.pdf

DIVERSE CELL TYPES, CIRCUITS, AND MECHANISMS FOR COLOR VISION IN THE VERTEBRATE RETINA

Wallace B. Thoreson and Dennis M. Dacey

Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, Nebraska; and Department of Biological Structure, Washington National Primate Research Center, University of Washington, Seattle, Washington

Physiol Rev 99: 1527–1573, 2019 Published May 29, 2019; doi:10.1152/physrev.00027.2018

https://journals.physiology.org/doi/pdf/10.1152/physrev.00027.2018

Human Vision

Introduction to color theory

https://graphics.stanford.edu/courses/cs178-10/applets/locus.html

COLOR WHEELS

https://www2.bellevuecollege.edu/artshum/materials/art/tanzi/Winter04/111/111CLRWHLSW04.htm

Human Vision and Color

UT

Click to access 121.pdf

COLOR VISION MECHANISMS

Andrew Stockman

Department of Visual Neuroscience UCL Institute of Opthalmology London, United KIngdom

David H. Brainard

Department of Psychology University of Pennsylvania Philadelphia, Pennsylvania

Color

CMU

Click to access lecture15.pdf

What Are The Characteristics Of Color?

Pantone

https://www.pantone.com/articles/color-fundamentals/what-are-the-characteristics-of-color

A Guide to Color


Guide C-316
Revised by Jennah McKinley

https://aces.nmsu.edu/pubs/_c/C316/welcome.html

A History of Color

The Evolution of Theories of Lights and Color
  • Robert A. Crone

https://link.springer.com/book/10.1007/978-94-007-0870-9

The Brilliant History of Color in Art

Victoria Finlay

A History of Light and Colour Measurement
Science in the Shadows

Sean F Johnston

University of Glasgow, Crichton Campus, UK

Color codes: modern theories of color in philosophy, painting and architecture, literature, music and psychology

Charles Riley

Chapter 6 Colour

History of Color Systems

Color and Imaging in Digital Video and Cinema

Color reproduction and management is a key task in digital video and cinema production. Choices of hardware, software, and handoffs and handshakes in production process require control over color of an image or a video. This is a very complex task due to several reasons.

  • Complexity of Color and its measurement
  • Changing color and light conditions during shoot indoors and outdoors
  • Hardware and software encoded color standards are inconsistent. Cameras, displays and projectors all have different color specifications.
  • After shoot, the data recorded is processed using different softwares for editing, grading, compositing, CG rendering, animations, and special effects. These softwares require different data formats (Log vs Linear).
  • After processing video data is required to meet different deliverables in multiple formats for displays and projectors.
  • Archiving and storage of data requires specific color formats.
  • There are also subjective and artistic requirements to meet look and feel of the data.

My post is to bring these issues to light and to educate. I hope after reading this post you know little more about color and its management during digital video and cinema production.

Key Terms

  • ACES
  • LUT
  • REC709
  • REC2020
  • Color Gamut
  • CIE Chromaticies
  • CIE XYZ
  • ACES 1.1
  • ACES 1.2
  • Color Workflow
  • Premier Pro
  • Final Cut Pro
  • Davinci Resolve
  • Avid Media Composer
  • IDT
  • ODT
  • RRT
  • Maya
  • Nuke
  • After Effects
  • ITU
  • SMPTE
  • AECS
  • ACES AP0
  • ACES AP1
  • BT 709
  • BT 2020
  • BT 2100 in 2016 to include HDR
  • HDR High Dymanic Range
  • HDR 10
  • SLog3
  • Fusion
  • Resolve
  • After Effects
  • OCIO
  • IDT
  • ODT
  • RRT
  • Red
  • Arri
  • Sony
  • Canon
  • Octane
  • CG
  • Linear representation of light
  • Gamma Curve
  • Log Gamma Curve
  • Log Profiles
  • Dynamic Range
  • Linearize work flow
  • Wide Gamut color space
  • Rendering engines
  • VRay
  • Arnold
  • Redshift
  • Octane
  • Cinema 4d
  • Blender
  • EXR linearize
  • Reference Rendering Transform
  • Color Manager OCIO
  • SLog
  • ACES CC
  • ACES CCT
  • Wave Form
  • DaVinci Resolve
  • After Effects
  • FS7
  • Rushes
  • Academy of Motion Picture Arts and Sciences
  • American Society of Cinematographers ASC
  • Digital Cinema Initiatives DCI
  • Society of Motion Picture and Television Engineers SMPTE
  • OpenColor IO
  • 32 bit per channel
  • 8 Bit
  • ACES CG Input
  • REC 709 Output

Human Vision

Source: https://z-fx.nl/ColorspACES.pdf

Color Models of Human Vision

Please see my two previous posts.

On Light, Vision, Appearance, Color and Imaging

Digital Color and Imaging

Digital Color

Source: What is 4K, UHD, SLog3, Rec 2020

The process of capturing and reproducing images requires a collaboration of camera sensors, file formats, rendering technologies, and display or printer technologies. All of these have different ways and different capabilities of representing color and intensity. In addition, they are all different from how our eyes work which further complicates things. As a result, over the years, several standards and processes have been implemented to accomplish this. They all involve some aspects of how to capture and store colors, what range of colors can be dealt with and how to adjust intensity to best reproduce the real world. To understand the new 4k technologies, including SLOG3, HDR, Rec 2020 etc, an understanding of the following is needed.

  • Gamut
  • Bit Depth
  • Gamma
  • Gamma Correction
  • Color spaces

Color Gamut

Source: https://z-fx.nl/ColorspACES.pdf

Color Capture in Digital Video and Cinema

Source: HOW DOES A DIGITAL CAMERA SENSOR WORK?

A modern digital camera’s sensor comes in one of two varieties generally. It will either be a Complementary Metal Oxide Semiconductor (CMOS), or a Charge-Coupled Device (CCD) sensor. The CCD type is mainly used in older models, but is still used on some modern cameras. Each type has its own advantages and disadvantages, but that is a topic for another article.

The most basic way you can understand how a sensor works is when the shutter opens, the sensor captures the photons that hit it and that is converted to an electrical signal that the processor in the camera reads and interprets as colors. This information is then stitched together to form an image. That is insanely over-simplified though.

The more complex answer is that a sensor is made up of millions of cavities called “photosites,” and these photosites open when the shutter opens and close when the exposure is finished (the number of photosites is the same number of pixels your camera has). The photons that hit each photosite are interpreted as an electrical signal that varies in strength based on how many photons were actually captured in the cavity. How precise this process is depends on your camera’s bit depth.

If we looked at a picture that was taken with just that electrical data mentioned earlier from the sensor, then the images would actually be in gray-scale. How we get colored images is by what’s known as a “Bayer filter array.” A Bayer filter is a colored filter placed over-top of each photosite and is used to determine the color of an image based on how the electrical signals from neighboring photosites measure. The colors of the filters are the standard red, green and blue, with a ratio of one red, one blue and two green in every section of four photosites.

Image for post
A graphic of light entering photosites with Bayer filters layered on. (graphic/Cambridge in Colour)

The red filter allows red light to be captured, the blue allows blue light in and the green allows green light in. The light that doesn’t match that photosites filter is reflected. This means that we are losing two-thirds of the light that can be captured and it is only of one color for each photosite. This forces the camera to guess what the amount of the other two colors is in each given pixel.

The data that is interpreted by the sensor with the Bayer filter array is what a RAW image file is.

The camera then goes through a process to estimate how much of each color of light there was for each photosite and colors the image based on that guessing.

Single Sensor Vs Multiple Sensors in Cameras

  • Sensor Type
    • CCD
    • CMOS
  • Sensor Size
    • Full Frame
    • APS-C
  • Sensor Numbers
    • Single – 1 CMOS or 1CCD
    • Multiple – 2CCD, 3CCD, 3CMOS
  • Sensor Pixels
    • 24 MP
    • 48 MP
  • Sensor Dynamic Range
    • Range of brightness sensor captures
    • 14 Stops
    • 20 Stops

A camera sensor can only capture a limited range of light. When a scene extends beyond that range of light, techniques such as filters, flash, and editing techniques can still create a dramatic, well-detailed image.

Comparison of different sensor sizes

Image Source: Camera Sensor Sizes Explained: What You Need to Know

Source: Camera Sensor Sizes Explained: What You Need to Know

Cameras with Single Image Sensor

With CFA Color Filter Array

  • Bayer CFA

Bayer CFA

Source:

Conversion of RAW files

Source: https://z-fx.nl/ColorspACES.pdf

Cameras with multiple Image Sensors

Cameras with multiple sensors do not require Bayer CFA.

  • 3 CCD – Single color info per sensor
  • 3 CMOS – Single color info per sensor
  • 4 CCD – Single color info per sensor plus Near Infra Red (NIR) info

Color Spaces in the Digital Video and Cinema

Image Source: Common Color Spaces

Gamut of Color Spaces

Color Space is characterized based on how much of its gamut covers the CIE Chromaticity Diagram.

Image Source: Why Every Editor, Colorist, and VFX Artist Needs to Understand ACES

Source: The Pointer’s Gamut
The coverage of real surface colors by RGB color spaces and wide gamut displays

Source: The Pointer’s Gamut
The coverage of real surface colors by RGB color spaces and wide gamut displays

Device Dependent Color Spaces

Capture Devices

Professional Cameras for Cinematography and Videography from

  • Sony
  • Canon
  • Arri
  • Red

Camera Sensor Dynamic Range

Image Source: Understanding 4K, Ultra HD and HDR

Conversion of RAW to Video Formats

Image Source: Understanding 4K, Ultra HD and HDR

Sony SLog Transfer Function

Image Source: Understanding 4K, Ultra HD and HDR

Sony Transfer Functions

Image Source: Understanding 4K, Ultra HD and HDR

Other Transfer Functions

Image Source: Understanding 4K, Ultra HD and HDR

Sony Color Spaces

Image Source: Understanding 4K, Ultra HD and HDR

Slog, Gamma, and Gamut

Source: Are S-Log and Color Space separate things?

S-log is a specific gamma, color space is a general term referring to gamuts. A very crude way of thinking is gamma refers to brightness and gamut refers to color.

It’s important to know which gamma and gamut you are recording in as this helps to ensure there is correct gamma and gamut mapping from capture to exhibition.

What is Gamma?

Gamma is also called Tone Mapping.

Source: What is 4K, UHD, SLog3, Rec 2020

Each pixel has a brightness level, which is the average of {red, green, blue} values, and this is called its luminance. In order to reproduce an image from capture to display, the luminance needs to be accurately reproduced. Since sensors and displays can have different luminance characteristics, there needs to be a mapping or relationship between a pixel’s numerical values and the actual luminance…this relationship is called the Gamma.

Linear Space is counter to Gamma Space or Log Space.

Log Space or Gamma Space

Log Curve simulates a non-linear curve. Log Color Profiles can be created for a camera.

  • Arri LogC
  • Cineon Dpx
  • RedLogFilm
  • Canon-Log

Source: LOG COLOR IN-DEPTH

Every professional camera manufacturer and almost every VFX and grading package has a Log workflow. Camera companies such as Arri, Sony, Canon, Red and many others implement their own flavors of Log color space. With the Log workflow it is possible to fit more dynamic range into an image and simulate nonlinear film response to light. The term Log is derived from the word logarithm, which is a fancy name for a function which outputs exponents for the given number.

Log Spaces of Different Brands

Source: LOG COLOR IN-DEPTH

Gamma Curve = Tone Curve = Log Curve

Log footage is an important part of the post-production workflow. Here’s what you need to know.

Source: UNDERSTANDING LOG AND COLOR SPACE IN COMPOSITING

As digital filmmaking becomes more and more affordable, technologies become increasingly available to colorists or post-production professionals. In this case, Log footage. The Log (logarithmic) color space has been around for quite a while. Initially high-end post houses used it with scanned film negatives in a color space called Cineon Log. Now, pretty much all camera manufacturers offer their own Log curve (or multiple). There is S-Log 2&3 (Sony), LogC (Arri), Canon LogV-Log (panasonic), Red LogfilmBlackmagic Log, etc. Each of them are different, usually tailored for the color science of the particular manufacturer’s products.

The biggest reason to use the Log color curve is how it retains the most dynamic range of information from the camera sensor (or film negative). It encodes what the camera sees logarithmically, meaning that the correlation between the exposure of the image (measured in stops) and the recorded image  is completely constant over a wider range. It utilizes more of the sensor’s information than a standard video curve because it’s saving as much data as possible rather than capturing specifically for the human eye or a video screen. This gives you much more color data to work with in post-production.

Linear Space

Source: Color Management/Blender

For correct results, different Color Spaces are needed for rendering, display and storage of images. Rendering and compositing is best done in scene linear color space, which corresponds more closely to nature, and makes computations more physically accurate.

Log Space to Linear Space Conversion

Source: LOG COLOR IN-DEPTH

In conclusion, to bring an image into the log color space all we need to do is to apply a logarithmic function which transforms values of pixels based on the log curves above. To linearize a log picture, we use an exponent function. Since the log color space is a mathematical transformation of values of pixels, it can be used with any types of file format, bit depth and channel. 

White Point

Is the color temperature of light. Outdoors, Indoor, Sunny, Cloudy conditions affect White Point. In Cameras white point can be adjusted depending on light conditions. D65 simulates daylight.

  • D50 – 5000 K
  • D60 – 6000 K
  • D65 – 6500 K

sRGB uses D65 vs ACES uses D60.

Source: https://z-fx.nl/ColorspACES.pdf

So do you understand these now?

  • LUT (Look Up Tables)
  • EOTF (Electro-Optical Transfer Function) – Linear to Non Linear or Log Conversion
  • OETF (Optio-Electro Transfer Function) – Log to Linear Conversion
  • Gamma Curve – Popular Name for EOTF
  • Gamma Correction
  • Log Curve (Non Linear Data)
  • Linear Curve (Linear Data)
  • High Dynamic Range HDR
  • Standard Dynamic Range SDR
  • White Point
  • IDT – Input Data Transform
  • ODT – Output Data Transform
  • Log LUT
  • f-Stops

A pair of Gamma and Gamut data is requied for encoding to display colors.

A device dependent RGB color space has standard primaries, gamma, and a whitepoint such as D50 or D65.

  • Primaries (R G B) for Color
  • Gamma for Luminance, and
  • White Point

Source: The Essential Guide to Color Spaces

Now that we’ve discussed these three parameters, here are some practical examples:

An Arri Alexa records media in Arri Wide Color Gamut, with an Arri Log C tone mapping curve, and a white point ranging from 2,000K to 11,000K.

A RED Dragon captures media in RedWideGamutRGB gamut, with a Log3G10 tone mapping curve, and a white point ranging from 1,700K to 10,000K (other gamut and gamma choices are available).

A cinema projector has a DCI-P3 gamut, a Gamma 2.6 tone mapping curve, and a standard illuminant D63 white point.

An SDR TV has a Rec 709 gamut, a Gamma 2.4 tone mapping curve, and a standard illuminant D65 white point.

Display Devices

  • Display Projectors
  • Television
  • Computer Monitors

Three advantages in newer display devices

  • Color
    • Color Space
    • Bit Depth
    • Gamma
    • Gamma Correction
  • Resolution
    • 4K vs 8K
  • Luminance
    • Nits

Image Source: What is 4K, UHD, SLog3, Rec 2020

Color Spaces used in Display Devices

Image Source: What is 4K, UHD, SLog3, Rec 2020

Display Resolution

Image Source: WHAT IS 4K, UHD, SLOG3, REC 2020

Bit Depth

Image Source: WHAT IS 4K, UHD, SLOG3, REC 2020

Color Specification using Color Management option in displays

Color Management in Digital Video and Cinema Production

In production of

  • Feature Film
  • Television
  • OTT
  • Live Production

SDR with REC 709 Color Space

Image Source: Understanding 4K, Ultra HD and HDR

SDR with S-Gamut3 and REC 2020

Image Source: Understanding 4K, Ultra HD and HDR

Process Flow

Image Source: Understanding 4K, Ultra HD and HDR

Live Production

Image Source: Understanding 4K, Ultra HD and HDR

Image Source: WHAT IS 4K, UHD, SLOG3, REC 2020

Operations during Production Process
  • Shoot
  • Convert
  • Edit/Grading
  • Conforming
  • Compositing/Rendering/VFX/CG
  • Convert
  • Deliverables
Color Space Hierarchy in Process Flows

  • Scene Referred – Input data has higher priority
  • Display Referred – Output data has higher priority

Source: https://z-fx.nl/ColorspACES.pdf

Source:

Process Flows in ACES

Source: https://z-fx.nl/ColorspACES.pdf

Source: https://z-fx.nl/ColorspACES.pdf

Working with ACES

Source: https://z-fx.nl/ColorspACES.pdf

CG and VFX Process Flows

Source: https://z-fx.nl/ColorspACES.pdf

The ‘Parts’ Of ACES

Source: Why Every Editor, Colorist, and VFX Artist Needs to Understand ACES

Even though ACES and its various transforms are quite mathematically complex, you can understand ACES better by understanding what each part or transform in the pipeline does.

Here’s the terminology for each of these transforms:

ACES Input Transform (aka: IDT or Input Device Transform)

The Input Transform takes the capture-referred data of a camera and transforms it into scene linear, ACES color space. Camera manufacturers are responsible for developing IDTs for their cameras but the Academy tests and verifies the IDTs. In future versions of ACES, the Academy may take on more control in the development of IDTs. IDTs, like all ACES transforms, are written using the CTL (Color Transform Language) programming language. It’s also possible to utilize different IDTs to compensate for different camera settings that might have been used.

ACES Look Transform (aka: LMT or Look Modification Transform)

The first part of what’s known as the ACES Viewing Transform (the Viewing Transform is a combination of LMT, RRT, & ODT transforms). LMTs provide a way to apply a look in a similar way to a Look Up Table (LUT). It’s important to note that the LMT happens after color grading of ACES data. Also, not every tool supports the use of LMTs.

RRT (Reference Rendering Transform)

Think of the RRT as the render engine component of ACES. The RRT converts scene referred linear data to an ultrawide display-referred data set. The RRT works in combo with the ODT to create viewable data for displays and projectors. While the Academy publishes the standard RRT, some applications have the ability to use customized RRTs (written with CTL). But many color correction systems do not provide direct access to the RRT.

ACES Output Transform (also known as the ODT or Output Device Transform)

The final step in the ACES processing pipeline is the ODT. This takes the high dynamic range data from the RRT and transforms it for different devices and color spaces. Like P3 or Rec 709, 2020, etc. Like IDTs and RRTs, ODTs are written with CTL.

Derivative Standards

Source: Why Every Editor, Colorist, and VFX Artist Needs to Understand ACES

There are also three main subsets of ACES used for finishing workflows called ACEScc, ACEScct and ACEScg:

  • ACEScc uses logarithmic color encoding and has the advantage of making color grading tools feel much more like they do when working in a log space that many colorists prefer.
  • ACEScct is just like ACEScc, but adds a ‘toe’ to the encoding. This means that lift operations respond similarly to traditional log film scans. This quasi-logarithmic behavior is described as being more milky, or foggier. ACEScct was added with the ACES 1.03 specification. It’s meant as an alternative to ACEScc based on the feedback of many colorists.
  • ACEScg utilizes linear color encoding and is designed for VFX/CGI artists so their tools behave more traditionally.

The ACES Pipeline

Source: Why Every Editor, Colorist, and VFX Artist Needs to Understand ACES

Now that we’ve defined the transforms used for ACES, understanding how the various transforms combine to form an ACES processing pipeline is pretty straightforward:

Camera Data -> Input Transform -> Color Grading -> Look Transform (optional) -> Reference Rendering Transform -> Output Transform

As mentioned, ACES is a hybrid color management system of scene referred/scene linear and display referred data.

Source: Why Every Editor, Colorist, and VFX Artist Needs to Understand ACES

Source: COLOUR MANAGEMENT BASICS

Source: COLOUR MANAGEMENT BASICS

Source: COLOUR MANAGEMENT BASICS

Source: COLOUR MANAGEMENT BASICS/Autodesk

Color Throttle

Because of bottlenecks in hardware and software, the color captured during the image/video capture process does not flow in its entirty to the displays of the users. Use of hardware and color spaces used during production process determines the output displayed. Color is thus throttled.

Color Throttle when using REC 709 Color Space

Image Source: BT.2020: How the Newest Color Range Standard Maximizes 4K Video Quality

Color Throttle when using REC 2020 Color Space

Image Source: BT.2020: How the Newest Color Range Standard Maximizes 4K Video Quality

Human Visual Dynamic Range Vs REC 2020 Range

Source: BT.2020: How the Newest Color Range Standard Maximizes 4K Video Quality

Source:

Softwares used in Post Production in Digital Video and Cinema

Source: digitalfilmpro.com

Video Editing Software and Hardware
  • Non Linear Editor
    • Avid Media Composer
    • Adobe Premiere Pro
    • Final Cut Pro
    • DaVinci Resolve – color correction plus NLE
    • Vegas Pro
  • Digital Audio Workstation
    • Avid Pro Tools
    • Apple Logic Pro X
    • Ableton Live 9
    • Cakewalk Sonar
    • Adobe Audition
  • Close-Captioning and Subtitling
    • Aegisub
    • NLEs
  • Edit Workstation
    • Edit Computer
    • Audio Equipment
    • File Sharing
      • KVM Extender
    • Editing Keyboard
    • Desk Chair
  • Digital Audio Transcipts

Creative Apps
  • RV
  • Adobe After Effects
  • Adobe Premiere Pro
  • SideFX Houdini
  • Unreal Engine
  • Unity
  • Perforce Helix Core
  • Adobe Creative Cloud
  • Adobe Illustrator
  • Autodesk 3DS Max
  • Autodesk Maya
  • Autodesk RV
  • Cinesync
  • Connect
  • Deadline
  • Foundry Hiero
  • Foundry Hiero Player
  • Foundry Nuke
  • Foundry Nuke Studio
  • Maxon Cinema 4D

Free Video Editing Tools
  • DaVinci Resolve
  • Lightworks
  • HitFilm Express
  • Avid Media Composer First
  • iMovie

Free Video Production Software Tools
  • Audacity – multitrack audio recorder
  • Ardour – DAW
  • GIMP- image editing
  • Blender – 3D Creation
  • Nuke Studio – Compositor – Node Based visual FX (VFX), editing, and finishing Studio
  • Blackmagic Fusion – Full feaured Compositor – Motion Graphics

3D Rendering Softwares
  • Unity
  • 3Ds Max Design
  • Maya
  • Cinema 4D
  • Blender
  • Keyshot
  • V-Ray
  • Lumion
  • SOLIDWORKS Visualize
  • Direct 3D
  • RenderMan
  • Redshift
  • Octane Render
  • Arnold
  • Maxwell
Color Management in Applications

Source: DISPLAY CALIBRATION & COLOR MANAGEMENT

Cameras for Video

Budget Cinema Cameras
  • Black Magic Pocket Cinema Camera
  • Black Magic Pocket Camera 4K
  • Z Cam E2C 4K Cine Camera MFT
  • Panasonic GH5

Best Cameras for Videographers

Source: Best cameras for videographers/DPREVIEW.COM

Published Nov 24, 2020

  • Panasonic Lumix DC – S1H
  • Panasonic Lumix DC-GH5
  • Canon EOS R6
  • Fujifilm X-T4
  • Nikon Z6
  • Nikon Z6 II
  • Panasonic Lumix Dc-GH5S
  • Sigma fp
  • Sony a7S III

Best 4K and 6K Cameras for Film making

Source: https://www.youtube.com/watch?v=o0muduTpveM&t=244s

  • Sony Alpha a7 III
  • Panasonic Lumix GH5S
  • Sony PXW FSM2
  • Panasonic Lumix S1H
  • Blackmagic Pocket Cinema 6K
  • Canon EOS C300 Mark II
  • Panasonic AU-EVA1
  • Blackmagic Design URSA Mini Pro G2
  • Sony PXW FS9
  • Canon C500 Mark II

Best Camcorders for Videographers

Source: Youtube

  • Panasonic HC-X2000
  • Sony PXW-Z280
  • Canon XA55
  • Panasonic AG-CX10
  • JVC GY-HC500U
  • Sony PXW-Z90
  • Panasonic HC-X1
  • Canon XF 705
  • JVC GY-HM250
  • Sony FDR -AX700

My Related Posts

Digital Color and Imaging

On Light, Vision, Appearance, Color and Imaging

Key Sources of Research

Why Every Editor, Colorist, and VFX Artist Needs to Understand ACES

Working with ACES in DaVinci Resolve

Oliver Peters

https://digitalfilms.wordpress.com/2020/10/02/working-with-aces-in-davinci-resolve/

Color Management and ACES Workflow

CG Cinematography

The Pointer’s Gamut
The coverage of real surface colors by RGB color spaces and wide gamut displays

Kid Jansen, Updated 19 February 2014

https://www.tftcentral.co.uk/articles/pointers_gamut.htm

ACES: Where Are We Now?

by Geoff Smith on August 14, 2020

https://www.abelcine.com/articles/blog-and-knowledge/tutorials-and-guides/aces-where-are-we-now

What is 4K, UHD, SLog3, Rec 2020

And other really boring things.

Compiled By Peter Morrone

BT.2020: How the Newest Color Range Standard Maximizes 4K Video Quality

BenQ

2020/05/29

https://www.benq.com/en-us/knowledge-center/knowledge/bt2020.html

Color Spaces in Visual Effects

Color Spaces

February 15, 2019

https://ciechanow.ski/color-spaces/

Chapter 1 Color Management

Color Spaces / MAYA/Autodesk

https://knowledge.autodesk.com/support/maya/learn-explore/caas/CloudHelp/cloudhelp/2020/ENU/Maya-Rendering/files/GUID-4410C27C-BB49-491B-AD13-14F48A8CCAAE-htm.html

Elle Stone’s Well-Behaved ICC Profiles and Code

https://ninedegreesbelow.com/photography/lcms-make-icc-profiles.html

ACES Workflow

Common Color Spaces

Color for Motion Pictures and Games

From Design to Display
  • Haarm-Pieter Duiker
  • Alex Forsythe
  • Stefan Luka
  • Thomas Mansencal
  • Jeremy Selan
  • Kevin Shaw
  • Nick Shaw

A VES Technology Committee White Paper
2019

https://nick-shaw.github.io/cinematiccolor/common-rgb-color-spaces.html

Cinematic Color From Your Monitor to the Big Screen

A VES Technology Committee White Paper Oct 17, 2012

Color Enhancement and Rendering in Film and Game Production: Color Management

Joseph Goldstone Lilliputian Pictures LLC

COLOR CORRECTION HANDBOOK:
Professional Techniques for Video and Cinema

Second Edition 

Alexis Van Hurkman

Peachpit Press http://www.peachpit.com

Colour Appearance Issues in Digital Video, HD/UHD, and D‐cinema

Charles Poynton

Understanding Color Management,

Second Edition

First published:18 July 2018

https://onlinelibrary.wiley.com/doi/book/10.1002/9781119223702

COLOR MANAGEMENT WITH CINEMA

Red

https://www.red.com/red-101/cinema-color-management

Digital Color Management

Encoding Solutions

Giorgianni, Edward J / Madden, Thomas E

The Basics of High Dynamic Range Media Explained [u]

Posted on July 27, 2019 by Larry

Understanding 4K, Ultra HD and HDR

Sony

COLOUR REPRODUCTION IN ELECTRONIC IMAGING SYSTEMS

PHOTOGRAPHY, TELEVISION, CINEMATOGRAPHY

Michael S Tooms

Digital Camera Reviews and Sensor Performance Summary

by Roger N. Clark

https://clarkvision.com/imagedetail/digital.sensor.performance.summary/

How to Use Dynamic Range for Stunning Photos in Bright Light

2 CCD , 3 CCD cameras, 4 CCD and 3 CMOS Cameras

http://www.adept.net.au/cameras/2CCD_3CCD_Cameras.shtml

CCD Sensors, Albert Einstein, and the Photoelectric Effect

https://www.radiantvisionsystems.com/blog/ccd-sensors-albert-einstein-and-photoelectric-effect

Color Management for Photographers – A Simplified Guide

Camera Sensor Sizes Explained: What You Need to Know

https://www.studiobinder.com/blog/camera-sensor-size/

Reading 15: Color

http://web.mit.edu/6.813/www/sp18/classes/15-color/

The Fundamentals of Camera and Image Sensor Technology

Jon Chouinard

Understanding color & the in-camera image processing pipeline for computer vision

Dr. Michael S. Brown

Digital Image Sensors

https://www.sensorland.com/HowPage090.html

Color Spaces, Log and Gamma

3.4 Color Spaces, Log and Gamma

LOG COLOR IN-DEPTH

Renderstory

Exploring the Basic Concepts of HDR: Dynamic Range, Gamma Curves, and Wide Color Gamut

Abhay Sharma

https://onlinelibrary.wiley.com/doi/pdf/10.1002/msid.1060

Understanding RGB Color Spaces for Monitors, Projectors, and Televisions

Abhay Sharma

First published: 26 March 2019

https://onlinelibrary.wiley.com/doi/full/10.1002/msid.1020

UHDTV – HDR and WCG

Understanding UHDTV Displays with PQ/HLG HDR, and WCG

https://www.lightspace.lightillusion.com/uhdtv.html

Color Management

https://docs.blender.org/manual/en/latest/render/color_management.html

Color Space Management: sRGB, Linear and Log

https://tiberius-viris.artstation.com/blog/3ZBO/color-space-management-srgb-linear-and-log

GAMMA AND LINEAR SPACE – WHAT THEY ARE AND HOW THEY DIFFER

https://www.kinematicsoup.com/news/2016/6/15/gamma-and-linear-space-what-they-are-how-they-differ

Are S-Log and Color Space separate things?

Understanding Log and Color Space In Compositing

RENDER COLOR SPACES

23 JUNE 2016

Anders Langlands

https://www.colour-science.org/anders-langlands/

Understanding High Dynamic Range (HDR) Imaging by Curtis Clark, ASC 

A Cinematographer Perspective

https://cms-assets.theasc.com/curtis-clark-asc-understanding-high-dynamic-range.pdf?mtime=20180502122857

Color Science Fundamentals in Motion Imaging

March 14, 2019 01:00 PM

https://www.smpte.org/events/color-science-fundamentals-in-motion-imaging

What is RAW Development?

Colour Management Basics

Autodesk Feb 2020

The Best Rendering Software for CG Lighting for Animation

by Tina Lee | Feb 14, 2019

C. A. Bouman: Digital Image Processing

January 7, 2020

The Essential Guide to Color Spaces

Cullen Kelly

Dell Color Management Software

User Manual

Adjusting for the Scene Adopted White

White Point Conversion

https://knowledge.autodesk.com/support/maya/learn-explore/caas/CloudHelp/cloudhelp/2016/ENU/Maya/files/GUID-2C925F6A-5A9C-4B2B-B732-90F4C3D2EB49-htm.html

A Complex Color Management Example

https://knowledge.autodesk.com/support/maya/learn-explore/caas/CloudHelp/cloudhelp/2016/ENU/Maya/files/GUID-7D579180-1E60-43DD-BB9C-0C00D1968F53-htm.html

Common Color Management Scenarios

https://knowledge.autodesk.com/support/maya/learn-explore/caas/CloudHelp/cloudhelp/2016/ENU/Maya/files/GUID-B2CD60E0-C100-45A4-9595-84D2DF98B268-htm.html

A Conversation about White Point and Digital Displays [Interview]

https://www.nanolumens.com/blog/an-imaginary-conversation-about-white-point-and-digital-displays/

Gamma and White Point Explained: How to Calibrate Your Monitor

https://blogs.scientificamerican.com/symbiartic/how-to-calibrate-your-monitor/

Why is the media white point of a display profile always D50?

http://www.color.org/whyd50.xalter

Colour Management for Video Editors

Display Calibration & Color Management

https://www.mysterybox.us/blog/2017/9/7/display-calibration-color-management

Color Communication

How does a digital camera sensor work?

Digital Color and Imaging

Digital Color and Imaging

In my previous post, I focused on Industrial Color Technology as used in Process Industries such as Paint, Plastics, Textiles, Paper, and Printing.

There are several useful links in the references section to color introduction which will be beneficial to people interested in digital colors and imaging.

On Light, Vision, Appearance, Color and Imaging

In this post, I have focused on another aspect of color technology as used in Digital Technology and Graphics Arts and Design Industry.

Devices for Digital Color and Imaging

  • Inkjet and Laser Printers
  • Displays on Desktop Computers and Mobile Devices
  • Television
  • Digital Cameras/Photography
  • Digital Video

Color Models

Not all color models listed below are device independent.

They represent human vision. These are international standards of color measurement. They were developed at diffrent times and are refinements on older models to mimic human vision and visual perception.

Image Source: COLOR PART 1: CIE CHROMATICITY AND PERCEPTION

RGB VS CMY Color Models

Image Source: BASICS OF COLOR IMAGING

List of Color Models

  • CIE x,y,Y
  • CIEXYZ
  • CIELAB
  • CIELCH
  • CIELUV
  • RGB
  • CMYK
  • HSB
  • HSV
  • HSL
  • HSI
  • YUV
  • YIQ
  • YCbCr
  • YPbPr

Color Models Classification

Image Source: UNDERSTANDING COLOR MODELS: A REVIEW

Uses of Color Models

Image Source: UNDERSTANDING COLOR MODELS: A REVIEW

Color Models Taxonomy

Image Source: UNDERSTANDING COLOR MODELS: A REVIEW

Image Source: COLOR IMAGES, COLOR SPACES AND COLOR IMAGE PROCESSING

Spot Colors Color Spaces

These color systems are used in Spot Printing in commercial printing applications.

  • ANPA
  • Colour Index International
  • DIC
  • PMS
  • FOCOLTONE
  • HKS
  • Munsell
  • NCS
  • Pantone
  • RAL
  • TOYO
  • Truematch

Image Source: A PRIMER TO COLORS IN DIGITAL DESIGN

Color Spaces

Are device dependent color models.

  • Adobe RGB 1998
  • sRGB
  • Apple RGB
  • ProPHOTO
  • Wide Gamut RGB
  • DCI-P3 or Display P3
  • P3 D65
  • P3 Theatrical
  • EBU Tech. 3213-E (Supersedes PAL)
  • oRGB
  • ECI RGB V2
  • ColorMatch RGB
  • Rec 2020
  • SWOP CMYK
  • HDTV RGB
  • NTSC RGB
  • CIE RGB
  • SGI RGB
  • PAL/SECAM RGB
  • SMPTE-240M RGB
  • SMPTE-C RGB
  • ACES RGB
  • Rec. 709 (ITU-R BT. 709)
  • Photo RGB
  • DCI-P3Pro
  • REC 209
  • scRGB
  • ROMM RGB
  • Arri LogC
  • RedWideGamutRGB
  • Bruce RGB
  • Ekta Space PS5
  • Don RGB 4
  • Beta RGB
  • Best RGB
  • Max RGB
  • Xtreme RGB
  • Ma RGBta

List of Color Spaces available in PhotoShop

Image Source: WHICH IS THE BEST COLOR SPACE FOR PHOTOGRAPHY: SRGB OR ADOBE RGB?

List of Color Spaces used in Videos/Cinema

Image Source: COMMON RGB COLOR SPACES

Color Gamut

Is range of color. Defines boundaries of color space. Number of Hues will be higher in a larger color gamut color space.

A color gamut is the defining a range of chromaticities—essentially a set of possible hues and their respective maximum saturations.

Image Source: UNDERSTANDING COLOR SPACE

Image Source: Beginner’s Guide to Color Space: RGB, CMYK, and Pantone

Color Management

Color spaces are used in

  • Capture of images, videos and Cinema
  • Editing and Processing of Images and Videos
  • Visual Displays on Computer Monitors, Phone and Tablet Displays, Digital Camera Displays, Digital Video Displays, Television, Cinema Screens, and LCD screens on Auto and Home appliances.
  • Printing of Images on Ink Jet printers, Laser printers, Screen Printing, Offset Printing etc.

Flows of Images from

  • Capture to Editing
  • Editing to Viewing on Media Devices
  • Editing to Printing on Media
  • Editing to Storage on Media Devices

Image Source: COLOR SPACE

Color Spaces used for different stages of the process

  • Capture – For Stills – Adobe RGB, sRGB; For Video -YUV
  • Editing – ProPhoto, Adobe RGB, sRGB, CIEXYZ, YUV
  • Viewing – sRGB
  • Printing – CMYK
  • Storage – sRGB, Adobe RGB, YUV, CMYK

Color Profiles

Color profiles define the specific color space (e.g. Adobe RGB) of a document or device. The terms color profile and color space are often used interchangeably.

Image Source: Digital Color Workflows and the
HP DreamColor LP2480zx Professional LCD Display

Please see the link below to learn about embedded color profiles. Since Color spaces are different, the tagged color profile is required for uniformity of image across different color spaces.

Color Filters

  • Bayer Array
  • Foveon X3

Source: COLOR FILTER ARRAY/Wikipedia

Color filters are needed because the typical photosensors detect light intensity with little or no wavelength specificity, and therefore cannot separate color information.[1] Since sensors are made of semiconductors they obey solid-state physics.

The color filters filter the light by wavelength range, such that the separate filtered intensities include information about the color of light. For example, the Bayer filter (shown to the right) gives information about the intensity of light in red, green, and blue (RGB) wavelength regions. The raw image data captured by the image sensor is then converted to a full-color image (with intensities of all three primary colors represented at each pixel) by a demosaicing algorithm which is tailored for each type of color filter. The spectral transmittance of the CFA elements along with the demosaicing algorithm jointly determine the color rendition.[2] The sensor’s passband quantum efficiency and span of the CFA’s spectral responses are typically wider than the visible spectrum, thus all visible colors can be distinguished. The responses of the filters do not generally correspond to the CIE color matching functions,[3] so a color translation is required to convert the tristimulus values into a common, absolute color space.[4]

Source: COLOR FILTER ARRAY/Wikipedia

Color BIT Depth

Defines details of a color image. More bit depth means more data storage per pixel of screen.

Color Gamut and Bit Depth defines color of an image.

What color Gamut was used and what bit depth was used in creating, editing, viewing, printing, and storing of an image?

Source: Human Vision and Digital Color Perception

The bit depth is what determines the color information of a digital image. The more bits stored in a pixel, the more information is stored and the greater the detail in color. The following is a guide of how many colors can be represented based on the number of bits.

1 Bit — 2 colors (Monochrome)
8 Bit — 256 colors (Low Color)
16 Bit — 65536 colors (High Color)
24 Bit — 16777216 colors (True Color)

Image Source: INTRODUCTION TO BASIC MEASURES OF A DIGITAL IMAGE FOR PICTORIAL COLLECTIONS

Rendering Intent

Image Source: A Breakdown Of Color Spaces | You Really Should Have A Grasp On This

Image Source: Choosing a color space: sRGB, Adobe RGB and ProPhoto RGB

Image Format during Image Capture

  • RAW
  • JPEG
  • JPEG2000

Using Color Filter Array, the color data is captured in RAW form. It then is converted to JPEG image file format.

Image Source: UNDERSTANDING DIGITAL RAW CAPTURE

Process Flows In Digital Color Imaging System

Image Source: SYSTEM OPTIMIZATION IN DIGITAL COLOR IMAGING

Digital Color Terminology

Image Source:

My Related Posts

On Light, Vision, Appearance, Color and Imaging

Key Sources of Research

Basics of Color Imaging

Yao Wang

Introduction to Color Imaging Science

HSIEN-CHE LEE

Digital Color Imaging

Gaurav Sharma, Member, IEEE, and H. Joel Trussell, Fellow, IEEE

Digital Color Imaging Handbook

Edited By Gaurav Sharma, Gaurav Sharma, Raja Bala

https://www.taylorfrancis.com/books/e/9781315220086/chapters/10.1201/9781420041484-1

HUMAN VISION AND DIGITAL COLOR PERCEPTION

Vince Tabora

HD Pro Blog

Medium.com

Understanding Chroma And Luminance In Digital Imaging

Vince Tabora

HD PRO

Medium.com

THE DIFFERENCE BETWEEN CMYK AND RGB IN DIGITAL PRINTING

https://www.decalimpressions.com/company-info/blog.html/article/2018/06/05/the-difference-between-cmyk-and-rgb-in-digital-printing

Some Common RGB Working Space Matrices

http://brucelindbloom.com/index.html?Eqn_RGB_XYZ_Matrix.html

Color Part 1:
CIE Chromaticity and Perception 

by Roger N. Clark

https://clarkvision.com/articles/color-cie-chromaticity-and-perception/

A Primer to Colors in Digital Design

Archit Jha

https://uxdesign.cc/a-primer-to-colors-in-digital-design-7d16bb33399e

Digital Color Workflows and the
HP DreamColor LP2480zx Professional LCD Display

RGB color space profiles

http://www.hutchcolor.com/profiles.html#freeRGBspaces

Video Colour Color Space for photographers

http://www.jamesmilnersmyth.com/video-colour-color-space-for-photographers/

Understanding Color Space

https://stephaniebryanphoto.com/myblog/understanding-color-space

Choosing a color space: sRGB, Adobe RGB and ProPhoto RGB

Information on Color Spaces and Rendering Intent

Canon

Understanding Color Models Used in Digital Image Processing

https://www.allaboutcircuits.com/technical-articleUnderstanding Color Models Used in Digital Image Processings/understanding-color-models-used-in-digital-image-processing/

Which is the Best Color Space for Photography: sRGB or Adobe RGB?

https://contrastly.com/which-is-the-best-color-space-for-photography-srgb-or-adobe-rgb/

How to Choose the Right Video Color Space

http://www.cinematiccolor.com/

Color Models

http://cs.brown.edu/courses/cs092/VA10/HTML/ColorModels.html

Color Space Mismatches

Colour Space Conversions

Adrian Ford (ajoec1@wmin.ac.uk <defunct>) and Alan Roberts (Alan.Roberts@rd.bbc.co.uk).

August 11, 1998(a)

UNDERSTANDING COLOR SPACES

Unraval

https://www.unravel.com.au/understanding-color-spaces

ColorPerfect, ColorNeg et al. and RGB / grayscale working spaces

https://www.colorperfect.com/working_spaces.html?lang=en

Color Space Names

Apple

https://developer.apple.com/documentation/coregraphics/cgcolorspace/color_space_names

History of the Very Odd sRGB Color Space

https://ninedegreesbelow.com/photography/srgb-history.html

color images, color spaces and color image processing

Ole-Johan Skrede 08.03.2017

INF2310 – Digital Image Processing

Department of Informatics
The Faculty of Mathematics and Natural Sciences University of Oslo

The Reversibility of Six Geometric Color Spaces

Tian-YuanShih

A Review of RGB Color Spaces

Beginner’s Guide to Color Space: RGB, CMYK, and Pantone

Color spaces, profiles and color management explained

https://lifeafterphotoshop.com/color-spaces-profiles-and-color-management-explained/

color space

PC Magazine

https://www.pcmag.com/encyclopedia/term/color-space

Digital-Image Color Spaces

Jeffrey Friedl’s Blog

Color Spaces and Digital Imaging

Higham, Nicholas J. 2015

The Essential Guide to Color Spaces

Cullen Kelly

Mathematical Representation of Color Spaces and Its Role in Communication Systems

Riyadh M. Al-saleem ,1 Baraa M. Al-Hilali ,2 and Izz K. Abboud

https://www.hindawi.com/journals/jam/2020/4640175/

Color Spaces and Color Profiles

https://www.dpbestflow.org/color/color-space-and-color-profiles

Good One

Commercial Printing

https://www.dpbestflow.org/color/commercial-printing

https://www.dpbestflow.org/links/31

Color Management Overview

https://www.dpbestflow.org/node/247

Describing, Specifying, and Using Digital Digital Color Space

NOVEMBER 18, 2002 

https://www.screenweb.com/content/describing-specifying-and-using-digital-digital-color-space

Introduction to Light, Color and Color Space

https://www.scratchapixel.com/lessons/digital-imaging/colors/color-space

The Color Space Conundrum

https://theasc.com/magazine/jan05/conundrum/index.html

A Breakdown Of Color Spaces | You Really Should Have A Grasp On This

A Standard Default Color Space for the Internet – sRGB

Michael Stokes (Hewlett-Packard), Matthew Anderson (Microsoft), 

Srinivasan Chandrasekar (Microsoft), Ricardo Motta (Hewlett-Packard)

Version 1.10, November 5, 1996

https://www.w3.org/Graphics/Color/sRGB.html

Color Models

https://scc.ustc.edu.cn/zlsc/sugon/intel/ipp/ipp_manual/IPPI/ippi_ch6/ch6_color_models.htm

COLOR SCIENCE AND COLOR APPEARANCE MODELS FOR CG, HDTV, AND D-CINEMA

Authors:
Charles A Poynton
Garrett M Johnson
Publication: SIGGRAPH ’04: ACM SIGGRAPH 2004 Course NotesAugust 2004

Color in Information Display Principles, Perception, and Models

Maureen C. Stone

StoneSoup Consulting

Course 20 SIGGRAPH 2004

oRGB: A Practical Opponent Color Space for Computer Graphics

Margarita Bratkova∗ Solomon Boulos† Peter Shirley‡ University of Utah

Color in Science, Art and Industry: The Inter-Society Color Council 75th Anniversary CD

ISCC

Image Processing 101

Color Theory Color Models

http://www.pengadprinting.com/content/color-theory-part-ii-types-color-and-uses-0

Color Models (RGB vs CMYK)

Understanding Color Models: A Review

1 Noor A. Ibraheem, 2 Mokhtar M. Hasan, 3 Rafiqul Z. Khan, 4 Pramod K. Mishra
1 Department of Computer Science, Faculty of Science, Aligarh Muslim University, Uttar Pradesh, India

Color Theory

Colorotate

RGB vs HSB vs HSL - Demystified

Anagh Sharma

https://www.anaghsharma.com/blog/rgb-vs-hsb-vs-hsl-demystified/

System Optimization in Digital Color Imaging

Understanding and exploiting interactions

Raja Bala and Gaurav Sharma

IEEE Signal Processing Magazine · February 2005

Digital image processing

Gonzalez and Woods, 

2nd edition, Prentice Hall, 2002

Which Color Space Should You Use When?

https://havecamerawilltravel.com/photographer/color-profiles/

DIGITAL IMAGING AND PHOTOGRAPHY

On Line Course

University of Delaware

https://www.eecis.udel.edu/~arce/courses/digitalimgproc/

Introduction to Basic Measures of a Digital Image for Pictorial Collections

Kit A. Peterson, Digital Conversion Specialist, June 2005

Prints & Photographs Division, Library of Congress, Washington, D.C. 20540-4730

Color spaces and gamut

Published on April 15, 2015   |  Updated on October 31, 2019

https://www.color-management-guide.com/color-spaces.html

COLOR IN DIGITAL CINEMA

Color Spaces

http://www.updig.org/guidelines/ph_color_spaces.html

https://danpgomez.com/tbl/2016/3/29/whats-the-difference-between-a-color-space-and-a-color-profile

Review and evaluation of color spaces for image/video compression

Samruddhi Y. Kahu1 | Rajesh B. Raut2 | Kishor M. Bhurchandi

Color Res Appl. 2019;44:8–33.

Color filter array

https://en.wikipedia.org/wiki/Color_filter_array#List_of_color_filter_arrays

Eyeing the Camera: into the Next Century

Richard F. Lyon and Paul M. Hubel

Foveon, Inc.
Santa Clara, California, USA

Color Filter Arrays: Design and Performance Analysis

Rastislav Lukac, Member, IEEE, and Konstantinos N. Plataniotis, Senior Member, IEEE

IEEE Transactions on Consumer Electronics, Vol. 51, No. 4, NOVEMBER 2005

Introduction to Bayer Filters

https://www.arrow.com/en/research-and-events/articles/introduction-to-bayer-filters

DIGITAL CAMERA SENSORS

https://www.cambridgeincolour.com/tutorials/camera-sensors.htm

https://www.cambridgeincolour.com

Rethinking Color Cameras

Ayan Chakrabarti

William T. Freeman

Todd Zickler

IEEE 2014

Color Filter Arrays for Quanta Image Sensors 

Omar A. Elgendy, Student Member, IEEE and Stanley H. Chan, Senior Member, IEEE

Quad Bayer sensors: what they are and what they are not

https://www.gsmarena.com/quad_bayer_sensors_explained-news-37459.php

Image sensor format

https://en.wikipedia.org/wiki/Image_sensor_format

Image file formats

https://en.wikipedia.org/wiki/Image_file_formats

Understanding Digital Raw Capture

Adobe

Why Every Editor, Colorist, and VFX Artist Needs to Understand ACES

Ben Bailey 2019

Common RGB Color Spaces

https://nick-shaw.github.io/cinematiccolor/common-rgb-color-spaces.html