Indigo is basically a dark, purplish blue. Many people liken it to the colour of the night sky on a clear evening. Making the colour indigo from scratch is quite simple. All you need is the colour red and blue and be able to mix well. You can mix just about any medium together (as long as the colours consist of red and blue) to make indigo. If you run out of indigo while you are painting, frosting a cake or making something from clay, you can create the colour yourself with minimal effort.
Add to your bowl two drops of blue paint.
Add to your bowl two drop of red.
Mix well with your paint brush. When you are done mixing you will have created the colour indigo.
The basic formula of two parts blue to one part red, will work with most colour items (food colouring or clay).