: RIT dye powder is what you needed so you're OK. Mix it in a separate cup with
: some water . . .

The dye powder is a very concentrated pigment. Don't mix the whole box in a cup of water! It will be way too concentrated.

Start with just a pinch, or less, and add water to dilute this as needed.

Or, mix a little of your colored water with your waterputty to get the color you desire, and then add clear water to get the consistency of the mix you need.

PGJ