Yes there are more complex systems out there but they cost a heck of a lot more than $1.99. It’s great for a quick breakdown into four values.

I want this to work because I need it, but This app does not work. Can’t select number of colors, but default appears to be 4. Using Pro. But only 3 colors appear. The menu items don’t describe what you can do. One item is “Zoom” which actually is where you are supposed to select number of colors but that option to change number is not there. Sometimes it changes different zones for a particular color than in a previous session on the same image. can not recommend

Pro version: 4 zones to edit with a range of colors from grey scale through some blues. I was expecting a little more control. You have no way to control which values in the image will shift and be assigned to the 4 zones, so you’re left with whatever the app chooses; your only other control is which new color of grey or blue you want those fields to be.If I would have demoed the premium version for 2 minutes I would not have paid $2.00 for the unlock.

The sliders for adjusting the color didn’t go off the box to where you can’t adjust that slider and if you could save the color adjustment after. I have a screenshot of the issue but nowhere to show it.