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 color is RGB, and may belong to any RGB color space, but an integral alpha value as invented by Catmull and Smith between 1971 and 1972 enables Alpha compositing. The inventors named alpha after the Greek letter in the classic linear interpolation formula αA + (1-α)B.
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.
PNG is an image format that uses RGBA.
Read more about RGBA Color Space: ARGB, RGBA Hexadecimal
Famous quotes containing the words color and/or space:
“For the profit of travel: in the first place, you get rid of a few prejudices.... The prejudiced against color finds several hundred millions of people of all shades of color, and all degrees of intellect, rank, and social worth, generals, judges, priests, and kings, and learns to give up his foolish prejudice.”
—Herman Melville (1819–1891)
“Not so many years ago there there was no simpler or more intelligible notion than that of going on a journey. Travel—movement through space—provided the universal metaphor for change.... One of the subtle confusions—perhaps one of the secret terrors—of modern life is that we have lost this refuge. No longer do we move through space as we once did.”
—Daniel J. Boorstin (b. 1914)