View Full Version : BlendMode: Color

12 December 2002, 03:25 AM

this question isn't about OpenGL, but I don't know where to ask..

We all know the BlendModes from GraphicProgramms (Darken, Lighten, Luminance, Burn, Exclusion etc) and there's one Mode Named "Color".

Can anyone tell me the formula of this Mode??
How can I calculate the result color of Red and Yellow..?

On some pages is writen something like:

Color mode:
The new HSL values consist of
...hue of the blend image
...saturation of the blend image
...lumniance of the base image

But it won't work.. I ever get a different color as if I use this effekt with PaintShop or PhotoShop...

I hope anyone can help me


Ian Jones
12 December 2002, 04:26 AM
If you have say a photo of a person, and you draw on a layer above.... the area of their hair with purple. Set this new layer to 'Colour' mode and it will change the hue and saturation of the underlying layer to purple but keep the luminosity (the light / dark values).

It is very similar to adjusting the hue / saturation in the image > adjust menu, except that you can target specific areas for colour changes.

12 December 2002, 12:00 PM
Yes... but how can I calculate the NewColor??

I need a Formula for this.. :(

Ian Jones
12 December 2002, 02:35 AM
Ahhh, so your obviously programming something then?

I can't help you there, you'll need to search for graphics programming with

I geuss you need to learn about different colour systems, HSL = Hue, Saturation, Luminosity...

You need to find a table or formula that can convert RGB into HSL or LAB etc....

12 December 2002, 04:33 AM
Scroll down to Color Conversion. Plenty of info to keep you busy for awhile. Some even include source code for various languages.

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