Masks are gray data, so your RGB color is converted to gray according to the profiles you are using.
But it sounds a lot like you might be using a bad profile or bad settings.
Also, the only time you "apply" a profile is when you convert colorspaces.
Thanks for the quick reply.
Could you explain a bit more what you mean by my RGB color being converted to gray? Is the mask channel using the gray color profile?
Oh, and one more observation: I was mistaken in my original post. It appears that the color profile is not actually affecting the layer mask. I can look at the mask and toggle the various profiles on and off and nothing changes - which is what I expect.
What the profile appears to be doing is limiting the range of values I can select from the color picker. Having a color profile that adjusts the output white point seems to prevent me from selecting completely white (1.0) in the color picker when I have the layer mask selected.
Ok, I did one more test to see whether I can use the eye dropper tool to select a "pure white" color even if the color picker does not let me do that. It turns out that I can.
So that is a work around... I am simply going to have to have an adjustment layer at the top of my layer pallette (but turned off) that has an all white mask. Even when it is turned off, I can simply select it, use the eye dropper tool to pick a pure white, and then return to my mask channel of choice and paint in full opacity.
In the mean time, I think the fact that the color profile still affects the color picker when a mask layer is active might be considered a bug. I'll probably report it as such.