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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 @@ <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> - <meta content="text/html; charset=ISO-8859-1" + <meta content="text/html; charset=windows-1252" http-equiv="Content-Type"> <title>Color Management</title> <meta content="Graeme W. Gill" name="author"> @@ -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.<br> + influence the choice of tradeoffs in dealing with practical + device limitations.<br> <br> 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 <span style="font-weight: bold;">Color Space</span>. <br> + 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 <span style="font-weight: bold;">Color Space</span>. + <br> <br> 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</span>). 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. <br> + 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. <br> <br> Many color devices have mechanisms for changing the way they respond to or reproduce color, and such features are called <span @@ -133,9 +134,8 @@ style="font-weight: bold;">Named</span> profiles represent color <span style="text-decoration: underline;">anchor points</span>. <span style="font-weight: bold;">Device Link</span> and <span - style="font-weight: bold;">Abstract</span> profiles represent <span - style="text-decoration: underline;">journeys</span> between anchor - points.<br> + style="font-weight: bold;">Abstract</span> profiles represent <u>connections</u> + or journeys between anchor points.<br> <br> <span style="font-weight: bold;">Device</span><br> <br> @@ -184,9 +184,8 @@ Two basic models can be used in ICC profiles, a <span style="font-weight: bold;">Matrix/shaper</span> model and a <span style="font-weight: bold;">cLUT</span> (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. <br> + Models often contain several processing elements that are applied + one after the other in order to provide an overall transformation. <br> <br> 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.<br> + flare/glare) can be modeled using (for example) CIECAM02 to modify + XYZ values.<br> <br> Another limitation relates to spectral assumptions. CIE XYZ uses a Standard Observer to convert spectral light values into XYZ values, |