High Priest Orven:
If you have dye powder, you may level up your dye by compounding it.
You can also use dyes to put patterns on your body and upgrade them.
Oh, you don't know about patterns, do you?
Open the Patterns and Hidden Power menu in the Inventory.
Click the Make pattern button at the bottom and a special will pop up. Pick a dye, press OK and a pattern will be applied.