Difference between revisions of "Glossary"

From GIMP Developer Wiki
Jump to: navigation, search
(edit C, GSoC)
(add cross-references)
Line 10: Line 10:
 
==A==
 
==A==
 
*'''{{term|A (uppercase)}}''' -  
 
*'''{{term|A (uppercase)}}''' -  
*:*The alpha channel in a color model, for instance in RGBA.
+
*:*The [[#alpha|alpha]]  channel in a color model, for instance in RGBA.
*:*In [[#babl|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.
+
*:*In [[#babl|babl]] the [[#alpha|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.
  
 
*'''{{term|a (lowercase)}}''' -  
 
*'''{{term|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.  
 
*:*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|babl]]: marks a color channel to be premultiplied with alpha, for instance RaGaBa is premultiplied alpha RGB
+
*:*In [[#babl|babl]]: marks a color channel to be premultiplied with [[#alpha|alpha]] , for instance RaGaBa is premultiplied alpha RGB
  
 
*'''{{term|Alpha}}''' - opacity. An alpha value of 0 means 'transparent', an alpha value of 100 means 'fully opaque', values in between mean 'partly opaque'.
 
*'''{{term|Alpha}}''' - opacity. An alpha value of 0 means 'transparent', an alpha value of 100 means 'fully opaque', values in between mean 'partly opaque'.
Line 24: Line 24:
 
*'''{{term|B (uppercase)}}''' -
 
*'''{{term|B (uppercase)}}''' -
 
*:*Blue color channel in the XYZ and RGB color models.
 
*:*Blue color channel in the XYZ and RGB color models.
*:*Brightness component of the HSB color model.
+
*:*[[#brightness|brightness]]  component of the HSB color model.
*:*In photography: symbol for luminance (e.g. brightness): obsolete, but may be found on older light meters. [[#2|[2]]]
+
*:*In photography: symbol for [[#brightness|brightness]]: obsolete, but may be found on older light meters. [[#2|[2]]]
 
*:*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. [[#2|[2]]]
 
*:*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. [[#2|[2]]]
  
Line 32: Line 32:
 
*'''{{term|babl}}''' - a dynamic, any to any, pixel format translation library. <br>See also: [http://www.gegl.org/babl babl website]
 
*'''{{term|babl}}''' - a dynamic, any to any, pixel format translation library. <br>See also: [http://www.gegl.org/babl babl website]
  
*'''{{term|brightness}}''' - attribute of a visual perception according to which an area or color appears to emit, or reflect, more or less light. This correlates directly with the amplitude of the light waveform. [[#1|[1]]] [[#4|[4]]] [[Translation glossary]]
+
*'''{{term|brightness}}''' - attribute of a visual perception according to which an area or color appears to emit, or reflect, more or less light. This correlates directly with the amplitude of the lightwave. [[#1|[1]]] [[#4|[4]]] [[Translation glossary]]
  
 
{{right|[[#Table of Contents|Table of Contents]]}}
 
{{right|[[#Table of Contents|Table of Contents]]}}
Line 39: Line 39:
 
*'''{{term|C (uppercase)}}''' -
 
*'''{{term|C (uppercase)}}''' -
 
*:*Cyan color component of the [[#CMY|CMY]] and [[#CMYK|CMYK]]  color model.
 
*:*Cyan color component of the [[#CMY|CMY]] and [[#CMYK|CMYK]]  color model.
*:*Chroma component of the LCH color space.
+
*:*[[#chroma|chroma]]  component of the LCH color space.
 
*:*the programming language most of GIMP is programmed in.
 
*:*the programming language most of GIMP is programmed in.
  
Line 50: Line 50:
 
*'''{{term|color temperature}}''' - temperature of an ideal black body radiator whose radiation has the same chromaticity as that of a given stimulus. Unit: K (Kelvin). [[#4|[4]]]
 
*'''{{term|color temperature}}''' - temperature of an ideal black body radiator whose radiation has the same chromaticity as that of a given stimulus. Unit: K (Kelvin). [[#4|[4]]]
  
*'''{{term|chroma}}''' - colorfulness of an area judged as a proportion of the brightness of a similarly illuminated area that appears white or highly transmitting. The higher the chroma, the more saturated this area appears. [[#1|[1]]] [[#4|[4]]]
+
*'''{{term|chroma}}''' - colorfulness of an area judged as a proportion of the [[#brightness|brightness]]  of a similarly illuminated area that appears white or highly transmitting. The higher the chroma, the more saturated this area appears. [[#1|[1]]] [[#4|[4]]]
  
 
*'''{{term|chromaticity}}''' - The color properties of a sample judged independently of luminance, i.e. in terms of hue and saturation only. [[#1|[1]]]
 
*'''{{term|chromaticity}}''' - The color properties of a sample judged independently of luminance, i.e. in terms of hue and saturation only. [[#1|[1]]]
Line 83: Line 83:
 
==K==
 
==K==
 
*'''{{term|K (uppercase)}}''' -  
 
*'''{{term|K (uppercase)}}''' -  
*:*Kelvin. Unit of color temperature.
+
*:*Kelvin. Unit of [[#color temperature|color temperature]] .
*:*Key-color component of the [[#CMYK|CMYK]]  color model to represent various shades of brightness. Usually black.
+
*:*Key-color component of the [[#CMYK|CMYK]]  color model to represent various shades of [[#brightness|brightness]] . Usually black.
 
   
 
   
 
{{right|[[#Table of Contents|Table of Contents]]}}
 
{{right|[[#Table of Contents|Table of Contents]]}}
Line 91: Line 91:
 
*'''{{term|LGM}}''' - Libre Graphics Meeting. Annual conference of developers and users of graphics open source software. GIMP has been participating for many years. [http://libregraphicsmeeting.org Website]
 
*'''{{term|LGM}}''' - Libre Graphics Meeting. Annual conference of developers and users of graphics open source software. GIMP has been participating for many years. [http://libregraphicsmeeting.org Website]
  
*'''{{term|light, linear}}''' - light as it is in nature and captured by camera sensors (and thus is in RAW images).
+
*'''{{term|light, linear}}''' - light as it is in nature and captured by camera sensors (and thus is encoded in RAW images).
  
 
*'''{{term|light, percepted}}''' - light as it is processed by eye and brain. The difference between linear and percepted light is that human eyes react to the same change of (linear) light with different sensitivity in dark or light environments.  Percepted light is the basis of color (e.g. color is the result of light, processed by eyes and brain).  
 
*'''{{term|light, percepted}}''' - light as it is processed by eye and brain. The difference between linear and percepted light is that human eyes react to the same change of (linear) light with different sensitivity in dark or light environments.  Percepted light is the basis of color (e.g. color is the result of light, processed by eyes and brain).  
Line 100: Line 100:
 
*'''{{term|M (uppercase)}}''' - Magenta color component of the [[#CMY|CMY]] and [[#CMYK|CMYK]]  color models.
 
*'''{{term|M (uppercase)}}''' - Magenta color component of the [[#CMY|CMY]] and [[#CMYK|CMYK]]  color models.
  
*'''{{term|Mired}}''' - former, obsolete unit of reciprocal color temperature.  
+
*'''{{term|Mired}}''' - former, obsolete unit of reciprocal [[#color temperature|color temperature]] .  
  
 
{{right|[[#Table of Contents|Table of Contents]]}}
 
{{right|[[#Table of Contents|Table of Contents]]}}

Revision as of 13:18, 5 January 2014

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 B C D E F G H I J K L M N O P Q R S T U V W X Y Z

References


A

  • '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

  • 'B (uppercase)' -
    • Blue color channel in the XYZ and RGB color models.
    • brightness component of the HSB color model.
    • In photography: symbol for brightness: obsolete, but may be found on older light meters. [2]
    • 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. [2]
  • 'b (lowercase)' - the axis in the CIELAB color space which denotes the blue-yellow component of the image. One end of the axis is blue and the other end yellow. [1]
  • 'babl' - a dynamic, any to any, pixel format translation library.
    See also: babl website
  • 'brightness' - attribute of a visual perception according to which an area or color appears to emit, or reflect, more or less light. This correlates directly with the amplitude of the lightwave. [1] [4] Translation glossary

C

  • 'C (uppercase)' -
    • Cyan color component of the CMY and CMYK color model.
    • chroma component of the LCH color space.
    • the programming language most of GIMP is programmed in.
  • 'CIE' - Commission Internationale de l´Eclairage (International Commission on Illumination). Independent, non-profit organization for recommendations on photometry and colorimetry. Its aim is to exchange information on all matters relating to the science and art of light and lighting, colour and vision, photobiology and image technology worldwide. It is recognized by ISO as an international standardization body. The CIE has defined several "color spaces" that describe the range of visible colors in unambiguous numerical terms. [1] [4]
  • 'CMY' - Cyan, Magenta, Yellow. The three "subtractive" primary colors used as the basis of all dye or pigment-based printing systems and color photography. A full range of colors including neutral grays and blacks can be produced with good cyan, yellow and magenta colorants (e.g. color film dyes) but typical printing inks are less than perfect. [1]
  • 'CMYK' - Cyan, Magenta, Yellow, Key color (usually Black). The four colors commonly used in process color printing. Black is added to CMY to enhance the density of dark areas and solve gray balance problems encountered when trying to make neutral grays with CMY alone. [1]
  • 'color temperature' - temperature of an ideal black body radiator whose radiation has the same chromaticity as that of a given stimulus. Unit: K (Kelvin). [4]
  • 'chroma' - colorfulness of an area judged as a proportion of the brightness of a similarly illuminated area that appears white or highly transmitting. The higher the chroma, the more saturated this area appears. [1] [4]
  • 'chromaticity' - The color properties of a sample judged independently of luminance, i.e. in terms of hue and saturation only. [1]

D

E

F

G

  • 'GEGL' - Generic Graphics Library, a graph based image processing framework. It is GIMP's foundation for nondestructive image editing in high bit depths. GEGL provides the infrastructure to do demand based, cached, nondestructive image editing on larger than RAM buffers. Through babl it provides support for a wide range of color models and pixel storage formats for input and output. GEGL support in current GIMP versions is experimental and will be official part of GIMP in version 2.10.
    See also: GEGL website, GEGL porting matrix
  • 'GSoC' - Google Summer of Code. Annual mentoring program hosted by Google Inc. to offer and award students to work on open source projects during summer. GIMP has been participating for many years.
    See also: GSoC website, GIMP's GSoC participation

H

I

J

K

  • 'K (uppercase)' -

L

  • 'LGM' - Libre Graphics Meeting. Annual conference of developers and users of graphics open source software. GIMP has been participating for many years. Website
  • 'light, linear' - light as it is in nature and captured by camera sensors (and thus is encoded in RAW images).
  • 'light, percepted' - light as it is processed by eye and brain. The difference between linear and percepted light is that human eyes react to the same change of (linear) light with different sensitivity in dark or light environments. Percepted light is the basis of color (e.g. color is the result of light, processed by eyes and brain).

M

  • 'M (uppercase)' - Magenta color component of the CMY and CMYK color models.

N

O

P

Q

R

S

T

U

V

W

X

Y

  • 'Y (uppercase)' -
    • Yellow color component of the CMY and CMYK color models.
    • In babl: grayscale color model.
    • relative luminance in XYZ color model.
    • luminance in xyY color model.

Z

References

1

CHROMiX ColorWiki

2

idigitalphoto dictionary

3

Wikipedia:HSL and HSV

4

CIE International Lighting Vocabulary