From 094535c010320967639e8e86f974d878e80baa72 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?J=C3=B6rg=20Frings-F=C3=BCrst?= Date: Fri, 1 May 2015 16:13:57 +0200 Subject: Imported Upstream version 1.7.0 --- doc/ColorManagement.html | 49 ++++++++++++++++++++++++------------------------ 1 file changed, 24 insertions(+), 25 deletions(-) (limited to 'doc/ColorManagement.html') diff --git a/doc/ColorManagement.html b/doc/ColorManagement.html index 50505cd..3adcbe8 100644 --- a/doc/ColorManagement.html +++ b/doc/ColorManagement.html @@ -1,7 +1,7 @@ - Color Management @@ -30,8 +30,8 @@ with the interaction of human vision and devices, allowing for such fundamental vision characteristics as white point adaptation and other phenomena. It should also allow the human end purposes to - influence the choice between  tradeoffs in dealing with - practical device limitations.
+ influence the choice of  tradeoffs in dealing with practical + device limitations.

The key means of implementing color management is to have a way of relating what we see, to the numbers that each device uses to @@ -40,13 +40,14 @@ The human eye is known to have 3 type of receptors responsible for color vision, the long, medium and short wavelength receptors. Because there are 3 receptors, human color perception is a 3 - dimensional phenomena, and therefore at least 3 channels are - necessary when communicating color information. Any device capable - of sensing or reproducing color must therefore have at least 3 - channels, and any numerical representation of a full range of colors - must have at least 3 components and hence may be interpreted as a - point in a 3 dimensional space. Such a representation is referred to - as a Color Space.
+ dimensional phenomena, and therefore at least 3 information channels + are necessary when communicating color information. Any device + capable of sensing or reproducing color must therefore have at least + 3 channels, and any numerical representation of a full range of + colors must have at least 3 components and hence may be interpreted + as a point in a 3 dimensional space. Such a representation is + referred to as a Color Space. +

Typically color capture and output devices expose their native color spaces in their hardware interfaces. The native color space is @@ -69,13 +70,13 @@ style="font-weight: bold;">CMYK). This is because a Cyan filters out Red wavelengths, Magenta filters out Green wavelengths, and Yellow filters out Blue wavelengths, allowing these colorants to - independently control how much RGB is emitted. Because it's - impossible to make filters that perfectly block C, M or Y - wavelengths without overlapping each other, C+M+Y filters together - tend to let some light through, making for an imperfect black. - Augmenting with an additional Black filter allows improving Black, - but the extra channel greatly complicates the choice of values to - create any particular color.
+ independently control how much RGB is reflected or transmitted. + Because it's impossible to make filters that perfectly block C, M or + Y wavelengths without overlapping each other, C+M+Y filters together + tend to let some light from broadband light sources through, making + for an imperfect black. Augmenting with an additional Black filter + allows improving Black, but the extra channel greatly complicates + the choice of colorant values to create any particular color.

Many color devices have mechanisms for changing the way they respond to or reproduce color, and such features are called Named profiles represent color anchor points. Device Link and Abstract profiles represent journeys between anchor - points.
+ style="font-weight: bold;">Abstract profiles represent connections + or journeys between anchor points.

Device

@@ -184,9 +184,8 @@ Two basic models can be used in ICC profiles, a Matrix/shaper model and a cLUT (Color Lookup Table) model. - Models often contain several optional processing elements that are - applied one after the other in order to provide an overall - transformation.
+ Models often contain several processing elements that are applied + one after the other in order to provide an overall transformation.

The Matrix/Shaper model consists of a set of per channel lookup curves followed by a 3x3 matrix. The curves may be defined as a @@ -234,8 +233,8 @@ common white point (D50), to facilitate ease of matching colors amongst devices with different white points. Other viewing condition effects (ie. image luminance level, viewing surround luminance and - flare/glare) can be modeled using (for example) using CIECAM02 to - modify XYZ values.
+ flare/glare) can be modeled using (for example) CIECAM02 to modify + XYZ values.

Another limitation relates to spectral assumptions. CIE XYZ uses a Standard Observer to convert spectral light values into XYZ values, -- cgit v1.2.3