While looking for the color you want to use from the real world, it is the painting can paint app

Introduction to use only “pencil color”
You want to use color, please look for using the iPhone / iPad camera
Locate the color out into the city, and try to draw a colorful picture!

It finds color can be rapidly save (it's free version and up to 10)
Are you may be good if a lot to find a color?