Scripts/Color Adjust

Color Adjust is an application that applies color adjustments on an image. The adjustment is the result of applying a linear-power transformation with coefficients: brightness B (-100..100), contrast C (0.2..5) and gamma G (0.2..5), to each pixel channel x (0..255) of the original image:

$\$f(x)=\,_{0}^{255}]\,B+C\,{\hat {x}}^{1/G},\quad \,_{a}^{b}]x=max\{a,min\{b,\lfloor x\rfloor \}\},\quad f({\hat {x}})=255\,f(x/_{255})\$$

The adjustment can be applied to separate or common RGB channels. The color curve plot shows the filter profile which maps the horizontal x input into vertical y.

The histogram shows input levels of the common RGB channel in the original image.

The image is loaded from a file using Addons/media/platimg. The result can be obtained as render verb of the application locale with 0 for separate and 3 for common RGB channels.

  a=. adjimg jpath'~system/examples/data/toucan.bmp'
     NB. ... make adjustments, but don't close the window ...
  (render__a 3) writeimg jpath'~temp/test.png'
  viewrgb readimg  jpath'~temp/test.png'

See Also

• Curve Pilot for Mac, Two Pilots
• Color Mechanic, Digital Light & Color
• Curves Tool for Color Corrections, Photoshop screencast
• Understanding Curves and Levels, Photoshop tutorial
• color curves, Google

Contributed by Oleg Kobchenko