So Im trying to add a layer mask over an image in Photoshop so that I can add a light color hue (changing the hue/saturation doesnt give me the effect I want) but when I try to use color the mask only lets me use black, white and gray. I have no idea why it does that and how to stop it from doing it or if theres nothing I can do to fix it.
Some screen captures of sample image whet you point out what you want to do and where would help. Layer mask are grayscale. A single selection channel.
It sounds like you might not be fully understanding how layer masks work.
You mention Hue/Sat for adding a colour cast. That is the usual method of doing this, but did you tick Colorize?
I'm following a video step by step online and having the same issue. I have tried clicking the colorize button when not having it clicked made no difference. Colors still does not change.
I'm following this video and not having the same effect, ie: cannot change the color as easily as it's shown here:
I cannot fully understand what exactly you are trying to do but did you tried to add layer with color above your image then to change blend mode to Hue or Color and to play with Opacity?
I'm having the exact same problem. Hue/saturation adjustment mask isn't changing the color in the image I've selected. The only slider that works is the Lightness and it changes the part of the image from light grey to black, but the hue slider doesn't change the color at all.
Please show a screenshot, including your layers panel and hue/saturation properties panel.