how to implement color balance from PhotoShop to graphic Mills

Hello Philippe,

In this case, you need to use AdjustHsl.Hue property. Hue is measured in degrees (from 0 degree to 360 degrees), where
0 degree is corresponded to Red color,
60 degrees to Yellow,
120 degrees to Green,
180 degrees to Cyan,
240 degrees to Blue,
300 degrees to Magenta. Please learn more in HSL model section.

In Graphics Mill values of Hue properties are in range [-1 1] (i.e. normalized at 360). Thus, you need to use -1 to set it to red, -2/3 to set it to Yellow, -1/3 to Green, etc. To implement functionality like Color Balance in Photoshop, you need to iterate values of Hue between 0 and -1 (Cyan <-> Red), between 2/3 and -1/3 (Magenta <-> Green), and between -2/3 and 1/3 (Yellow <-> Blue).