Specifications

Print2CAD OCR 2013- 111
Print2CAD
OCR 2013
17.4.2 RGB Color Space
“An RGB color space is any additive color space based on the RGB color model. A
particular RGB color space is dened by the three chromaticities of the red, green, and
blue additive primaries, and can produce any chromaticity that is the triangle dened by
those primary colors. The complete specication of an RGB color space also requires
a white point chromaticity and a gamma correction curve. RGB is an acronym for Red,
Green, Blue.
An RGB color space can be easily understood by thinking of it as “all possible colors”
that can be made from three colourants for red, green, and blue. Imagine, for example,
shining three lights together onto a white wall: one red light, one green light, and one
blue light, each with dimmer switches. If only the red light is on, the wall will look red.
If only the green light is on, the wall will look green. If the red and green lights are on
together, the wall will look yellow. Dim the red light some and the wall will become more
of a yellow-green. Dim the green light instead, and the wall will become more orange.
Bringing up the blue light a bit will cause the orange to become less saturated and more
whitish. In all, each setting of the three dimmer switches will produce a different result,
either in color or in brightness or both.
An LCD display can be thought of as a grid of thousands of little red, green, and blue
light bulbs, each with their own dimmer switch. The gamut of the display will depend on
the three colors used for the red, green, and blue lights. A wide-gamut display will have
very saturated, “pure” light colors, and thus be able to display very saturated deep colors.”
Source: Wikipedia, subject “RGB Color Space”
License Agreement: http://creativecommons.org/licenses/by-sa/3.0/
17.4.3 RGBA Color Space
“RGBA stands for Red Green Blue Alpha. While it is sometimes described as a color
space, it is actually simply a use of the RGB color model, with extra information.
The alpha channel is normally used as an opacity channel. If a pixel has a value of 0%
in its alpha channel, it is fully transparent (and, thus, invisible), whereas a value of
100% in the alpha channel gives a fully opaque pixel (traditional digital images). Values
between 0% and 100% make it possible for pixels to show through a background like a
glass (translucency), an effect not possible with simple binary (transparent or opaque)
transparency. It allows easy image compositing. Alpha channel values can be expressed
as a percentage, integer, or real number between 0 and 1 like RGB parameters. (...)”
Source: Wikipedia, subject “RGBA Color Space”
License Agreement: http://creativecommons.org/licenses/by-sa/3.0/