Color Theory/HDR

HDR

DR
Dynamic range (DR):
 * is the ratio between the largest and smallest values that a certain quantity can assume. It is often used in the context of signals, like sound and light. That technology also improves other aspects of transmitted images, such as color gamut
 * The maximum contrast of an image is the contrast ratio or dynamic range

types of DR:
 * LDR = low DR
 * SDR (Standard Dynamic Range): 0.05 nits - 100 nits
 * HDR (High Dynamic Range): 0.0005 nits - 10,000 nits. Also known as wide dynamic range, extended dynamic range, or expanded dynamic range, is a dynamic range higher than usual.
 * Human DR: Human vision: can detect brightness levels as low as 0.000001 nits and as high as 100,000,000 nits

The candela per square metre is the unit of liminance in the International System of Units. The nit (symbol: nt) is a non-SI name also used for this unit

1 nt = 1 cd/m2

Defining HDR image and image sequence formats and attributes
 * Peak luminance
 * White points
 * Contrast – spatial and temporal
 * Dark levels

3 levels of monitor brightness:
 * a low brightness if they have a peak brightness below 300 nits
 * a standard brightness if they have a peak brightness between 300 and 350 nits (SDR)
 * a high brightness if they have a peak brightness above 350 nits ( HDR )

High dynamic range (HDR)
 * HDR rendering
 * HDR TV

HDR
 * HDRI = High dynamic range imaging. The set of imaging technologies and techniques that allow to increase the dynamic range of images or videos. It covers the acquisition, creation, storage, distribution and display of images and videos
 * HDRR = High-dynamic-range rendering
 * HDRP = HIGH DEFINITION RENDER PIPELINE
 * HDR display
 * HDR file formats

formats
Formats that are only used for HDR storage purpose:
 * AVIF
 * Raw image formats
 * Formats that use a linear transfer function with high bit-depth
 * Formats that use a logarithmic transfer function
 * OpenEXR
 * ACES

HDR formats that can be used for both storage and transmission to displays, such as:
 * HDR10
 * HDR10+
 * Dolby Vision
 * HLG

programs

 * HDRI / Radiance image processing algorithms for Python
 * piccante: The hottest High Dynamic Range (HDR) Library

links

 * High Dynamic Range Explained by Eric Chan 10-10-2023
 * displayhdr.org
 * Learn OpenGL: HDR
 * hdr-faq by ARRI
 * greg benz photography: hdr
 * Towards an HDR-capable ICC PCS by Chris Lilley World Wide Web Consortium (W3C) June 2020