ColorspaceType

Specify the colorspace that quantization (color reduction and mapping) is done under or to specify the colorspace when encoding an output image. Colorspaces are ways of describing colors to fit the requirements of a particular application (e.g. Television, offset printing, color monitors). Color reduction, by default, takes place in the RGBColorspace. Empirical evidence suggests that distances in color spaces such as YUVColorspace or YIQColorspace correspond to perceptual color differences more closely than do distances in RGB space. These color spaces may give better results when color reducing an image.

When encoding an output image, the colorspaces RGBColorspace, CMYKColorspace, and GRAYColorspace may be specified. The CMYKColorspace option is only applicable when writing TIFF, JPEG, and Adobe Photoshop bitmap (PSD) files.

Values

ValueMeaning
UndefinedColorspace

No colorspace has been specified.

RGBColorspace

Linear RGB colorspace

GRAYColorspace

Full-range grayscale

TransparentColorspace

The Transparent color space behaves uniquely in that it preserves the matte channel of the image if it exists.

OHTAColorspace

Red-Green-Blue colorspace

LabColorspace

ditto

XYZColorspace

CIE XYZ

YCbCrColorspace

Kodak PhotoCD PhotoYCC

YCCColorspace

ditto

YIQColorspace

Y-signal, U-signal, and V-signal colorspace. YUV is most widely used to encode color for use in television transmission.

YPbPrColorspace

ditto

YUVColorspace

ditto

CMYKColorspace

Cyan-Magenta-Yellow-Black colorspace. CYMK is a subtractive color system used by printers and photographers for the rendering of colors with ink or emulsion, normally on a white surface.

sRGBColorspace

Kodak PhotoCD sRGB.

HSBColorspace

Hue, saturation, luminosity

HSLColorspace

ditto

HWBColorspace

Hue, whiteness, blackness

Rec601LumaColorspace

Luma (Y) according to ITU-R 601

Rec601YCbCrColorspace

YCbCr according to ITU-R 601

Rec709LumaColorspace

Luma (Y) according to ITU-R 709

Rec709YCbCrColorspace

YCbCr according to ITU-R 709

LogColorspace

Red-Green-Blue colorspace

CMYColorspace

Cyan-Magenta-Yellow-Black colorspace. CYMK is a subtractive color system used by printers and photographers for the rendering of colors with ink or emulsion, normally on a white surface.

LuvColorspace

CIE 1976 (L*, u*, v*) color space.

HCLColorspace

HCL is a color space that tries to combine the advantages of perceptual uniformity of Luv, and the simplicity of specification of HSV and HSL.

LCHColorspace

Alias for LCHuv.

LMSColorspace

LMS is a color space represented by the response of the three types of cones of the human eye, named after their responsivity (sensitivity) at long, medium and short wavelengths.

LCHabColorspace

CIE 1976 cylindrical version of Lab.

LCHuvColorspace

CIE 1976 cylindrical version of Luv

scRGBColorspace

scRGB is a wide color gamut RGB (Red Green Blue) color space created by Microsoft and HP that uses the same color primaries and white/black points as the sRGB color space but allows coordinates below zero and greater than one.

HSIColorspace
HSVColorspace
HCLpColorspace
YDbDrColorspace
xyYColorspace

In CIE xyY, Y is the luminance and x and y represents the chrominance values derived from the tristimulus values X, Y and Z in the CIE XYZ color space.

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