SRGB: Difference between revisions

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Due to the standardization of sRGB on the Internet, on computers, and on printers, many low- to medium-end consumer [[digital camera]]s and [[image scanner|scanners]] use sRGB as the [[default (computer science)|default]] (or only available) working color space. However, consumer-level [[charge-coupled device|CCDs]] are typically uncalibrated, meaning that even though the image is being labeled as sRGB, one can not conclude that the image is color-accurate sRGB.
 
If the color space of an image is unknown and it is an 8&nbsp;bit image format, sRGB is usually the assumed default, in part because color spaces with a larger gamut need a higher bit depth to maintain a low color error rate (∆E). An [[ICC profile]] or a [[look uplookup table]] may be used to convert sRGB to other color spaces. ICC profiles for sRGB are widely distributed, and the ICC distributes several variants of sRGB profiles,<ref name="ICCspec">[https://color.org/srgbprofiles.xalter sRGB profiles], ICC</ref> including variants for ICCmax, version 4, and version 2. Version 4 is generally recommended, but version 2 is still commonly used and is the most compatible with other software including browsers. Version 2 of the ICC profile specification does not officially support piecewise parametric curve encoding ("para"), though version 2 does support simple power-law functions.<ref name="ICCspec" /> Nevertheless, lookup tables are more commonly used as they are computationally more efficient.{{citation needed|date=November 2021}} Even when parametric curves are used, software will often reduce to a run-time lookup table for efficient processing.{{citation needed|date=November 2021}}
 
As the sRGB gamut meets or exceeds the gamut of a low-end [[inkjet printer]], an sRGB image is often regarded as satisfactory for home printing. sRGB is sometimes avoided by high-end print publishing professionals because its color gamut is not big enough, especially in the blue-green colors, to include all the colors that can be reproduced in [[CMYK]] printing. Images intended for professional printing via a fully color-managed workflow (e.g. [[prepress]] output) sometimes use another color space such as [[Adobe RGB color space|Adobe RGB (1998)]], which accommodates a wider gamut. Such images used on the Internet may be converted to sRGB using [[color management]] tools that are usually included with software that works in these other color spaces.
 
The two dominant programming interfaces for 3D graphics, [[OpenGL]] and [[Direct3D]], have both incorporated support for the sRGB gamma curve.
 
OpenGL supports [[Texturetexture mapping|textures]] with sRGB gamma encoded color components (first introduced with EXT_texture_sRGB extension,<ref>{{cite web |title=EXT_texture_sRGB |date=24 January 2007 |url=https://www.khronos.org/registry/OpenGL/extensions/EXT/EXT_texture_sRGB.txt |date=24 January 2007 |access-date=12 May 2020}}</ref> added to the core in OpenGL 2.1) and rendering into sRGB gamma encoded [[framebuffer]]s (first introduced with EXT_framebuffer_sRGB extension,<ref>{{cite web |title=EXT_framebuffer_sRGB |date=17 September 2010 |url=https://www.khronos.org/registry/OpenGL/extensions/EXT/EXT_framebuffer_sRGB.txt |date=17 September 2010 |access-date=12 May 2020}}</ref> added to the core in OpenGL 3.0). Correct [[mipmap]]ping and [[interpolation]] of sRGB gamma textures has direct hardware support in texturing units of most modern [[GPU]]s (for example nVidia GeForce 8 performs conversion from 8-bit texture to linear values before interpolating those values), and does not have any performance penalty.<ref>{{cite web |title=GPU Gems 3: Chapter 24. The Importance of Being Linear, section 24.4.1 |publisher=NVIDIA Corporation |url=https://developer.nvidia.com/gpugems/gpugems3/part-iv-image-effects/chapter-24-importance-being-linear |publisher=NVIDIA Corporation |access-date=3 March 2017}}</ref>
 
== sYCC ==