Hi all Hope someone here can help. I can do this with paint but not in digital! When I try to decrease the saturation of a given color in the LAB/color picker boxes, it automatically gets lighter, with 0% saturation being white. If I'm starting with say a purple of value 5, what I need is for the final desaturated color to be a grey of value 5. I have tried doing this by hand, decreasing the saturation and lightness manually until I get close to what I want. Then I used "desaturate" on a square of the 100% saturated color and, say, a square of the 70% saturated color. My thinking was if they both convert to the same grey tone then I have the same value in the 100 and 70% colors. Unfortunately, this only seems to work with a few colors - for example if I use red and desaturate the two squares, one is darker than the other. If I adjust the color so the desaturation command gives me the same grey, one is now lighter than the other. This is driving me crazy. Is there a color palette out there that maintains the value constant as the saturation dereases? Or a function in photoshop where hue / lightness and saturation are actually independent of each other? Thanks so much D'Arcy

Image/adjust/hue-saturation Three sliders Hue, saturation, brightness. If you don't like the effect of the saturation slider, lower the brightness slider to make it darker.

i find that if i just paint with a colour and click on the forground colour and move the HSB sliders (this does not convert the image)toward grey, it works ok, but as far as entire image effects goes... perhaps a new layer, fill it with black, the layer mode is 'colour' this will give you the image in grey scale (similar if not the same as 'desaturate) but the *L channel automaticly gives you the luminosity (and is grey scale) of certain colours _there are disparities between a desaturation and the *L channel the info pallette, can give you the % of grey that a colour has without conversion, but i think you will have to find a new kind of purple untill you get one that is 5% black, in the info

Message edited on: 01/07/2005 13:06

Thanks for your replies. I tried all suggestions :-)
Unfortunately, each one produces a different effect, and none of them are what I am looking for. In the attached pic, I started from a mid-saturated red and green. I then changed the saturation to either 0% or 100% with various methods.

As you can see, the two "Slider" methods both change the brightness when I alter the saturation. Doing it by eye is most accurate but tedious. Using the info box and "K" values is very close but also very tedious, trial and error for each color since you have to check it, make a guess in the color picker, paint a new dot and check it again, etc.

Using the new layer set to "color" method to check brightness also gives results that do not match the actual brightness/darkness of the colors in question, as does the "desaturate" command.

I'm at the point of spending the next 6 months working out a palette by hand - aaarrgghhhh.

Does anybody have any other thoughts? I really do appreciate the time you all took to answer my first post.

thank you all

D.