Zorka wrote:
To extract COLOR:

Layer 1: Make a solid 50% gray layer, blend mode normal
Layer 2: Make a copy of your background/desired image, blend mode to color, and put it ABOVE a solid 50% gray layer
Layer 3: Create a stamp/merge visible layer from Layer 1 and Layer 2


To extract LUMINOSITY/TONE:

(Turn all layers visibility off except a background/desired image layer)

Layer 4: Make a solid 50% gray layer, blend mode to color and put it ABOVE a background/desired image layer
Layer 5: Create a stamp/merge visible layer from background layer and Layer 4


To PUT COLOR & LUMINOSITY/TONE TOGETHER:

Layer 5 (stamped luminosity) under, mode normal
Layer 3 (stamped color) above, mode color

This only works 100% when working in Prophoto RGB, in Adobe or sRGB the result image is not 100% equal to the original.

DerW made an interesting video/action that works quite good for sRGB.

GIMP grain extract mode can separate luminosity/chroma

Pictus wrote:
video/action that works quite good for sRGB.

GIMP grain extract mode can separate luminosity/chroma

That's what I was looking for, thanks Pictus.

Pictus wrote:
This only works 100% when working in Prophoto RGB, in Adobe or sRGB the result image is not 100% equal to the original.

I disagree. After doing so, I've made a stamp (I'm working on Adobe RGB) of the COLOR + TONE and set it to a difference mode to see if there were ANY differences between this one and the original image. What I've got is completely black image which means that there are NO differences at all.

NothingIsRealButTheGirl wrote:

Well the brute force way would be to match model the face in 3D and light it white.

I don't know what algorithm the company I posted uses.

Anther way (for a single frame) would be to try and hand paint it by eye and feel. Do a 'paint-over' on top of the original.

The reason I say you have to estimate the illumination is because no simple algorithm is going to know WHY a color looks the way it does unless it knows the illumination and geometry of the scene.



A and B are the same value in the above.

Krunoslav-Stifter wrote:
Hey, guys. How would you isolate color in an image?
I want to split the image into color only and tone/light only. Like this.




Tone is simply B&W. But I'm not sure how to isolate the color in an image without the tone. Any suggestions? Thanks.

So if you really want diffuse reflection in one image and illumination in the other then you have to do something like I described.

If you just want to disassemble an image into some sort of color and luminosity channels and reassemble it then that's another matter.

Zorka wrote:
I disagree. After doing so, I've made a stamp (I'm working on Adobe RGB) of the COLOR + TONE and set it to a difference mode to see if there were ANY differences between this one and the original image. What I've got is completely black image which means that there are NO differences at all.

This is what I get when working in sRGB or Adobe RGB
You can test with https://www.modelmayhem.com/po.php?thre … st18278782

Pictus wrote:
This is what I get when working in sRGB or Adobe RGB
You can test with https://www.modelmayhem.com/po.php?thre … st18278782

You are absolutely right, I didn't take a different colors into consideration so I guess I owe you a drink! :wink wink:

P.S. You're THE BEST and you know it.

Krunoslav-Stifter wrote:
Tone is simply B&W. But I'm not sure how to isolate the color in an image without the tone. Any suggestions? Thanks.

In a lit scene illumination is not always just black and white. A scene could be lit with lights having color other than pure white.

So if you really do mean pure b&w 'tone,' (value), then you can do everything you want with blend modes. If you are, on the other hand, trying to decouple illumination from diffuse color for 3D CG purposes, then what I'm saying applies.

Pictus wrote:
DerW made an interesting video/action that works quite good for sRGB.

I haven't tried it but this seems to be the correct maths for A=B+C

NothingIsRealButTheGirl wrote:
If you just want to disassemble an image into some sort of color and luminosity
channels and reassemble it then that's another matter.

Yeah, it's for teaching purposes so it's more for illustration and I think I found what I was looking for. Thanks for all the help.

NothingIsRealButTheGirl wrote:
So if you really do mean pure b&w 'tone,' (value), then you can do everything you want with blend modes. If you are, on the other hand, trying to decouple illumination from diffuse color for 3D CG purposes, then what I'm saying applies.

no, it's just for illustrative purposes so I think B&W or any of the suggested methods will do. Thanks.

Zorka wrote:
You are absolutely right, I didn't take a different colors into consideration so I guess I owe you a drink! :wink wink:

CHEERS! :wink wink:

Zorka wrote:
P.S. You're THE BEST and you know it.

Thanks, but...
Then I woke up! LoL
You super!!

BTW, guys&girls some interesting stuff:
-Shadow colours and Munsell Colour Space
http://www.broadhurst-family.co.uk/left … unsell.htm
-Munsell Color Studies
http://munsellcolor.webnode.pt/

Krunoslav-Stifter wrote:

Yeah, it's for teaching purposes so it's more for illustration and I think I found what I was looking for. Thanks for all the help.

One interesting thing painters figured out a long time ago is that you can get pretty crazy with the color without hurting readibility as long as the values are correct.



http://idrawgirls.com/tutorials/2011/10 … r-artists/

NothingIsRealButTheGirl wrote:

One interesting thing painters figured out a long time ago is that you can get pretty crazy with the color without hurting readibility as long as the values are correct.

Thanks.