From GIMP Developer Wiki
Revision as of 21:27, 3 January 2014 by Scl
This glossary holds definitions important for the GIMP development. These include functional definitions i.e. from computer graphics and color theory, photography, terms from BABL and GEGL etc.
Table of Contents
- A (uppercase) -
- The alpha channel in a color model, for instance in RGBA.
- In babl the alpha value in a color model. If combined with alpha-premultiplied color channels: the alpha value each color channel R, G, B was multiplied with to achieve Ra, Ga, Ba. Needed to get from RaGaBa back to RGB. The same applies to R'aG'aB'aA, YaA, Y'aA.
- a (lowercase) -
- The axis in the CIELAB color space which denotes the magenta-green component of the image. One end of the axis is green and the other end magenta.
- In babl: marks a color channel to be premultiplied with alpha, for instance RaGaBa is premultiplied alpha RGB
- Alpha - opacity. An alpha value of 0 means 'transparent', an alpha value of 100 means 'fully opaque', values in between mean 'partly opaque'.
- B (uppercase) -
- Blue color channel in the XYZ and RGB color models
- In photography: symbol for luminance (e.g. brightness): obsolete, but may be found on older light meters. 
- Bulb (in photography): Used for long exposures timed by the photographer. Setting for shutter at which shutter opens when shutter button is pressed and stays open as long as shutter button is kept down.
- babl - a dynamic, any to any, pixel format translation library. (Website)