Colouring the glass
I create a new layer, place it under the stained glass frame and began to paint. I choose saturated colours because I know I’ll be blurring them later on. At the top of the glass I add simple splashes of colour. I don’t need to pay too much attention to those colours because they’ll be indistinct in the finished image.
Merge colour layers
I merge the colour layer with the black line art and I set it to Color Dodge in the Layers palette. Everything that was black becomes transparent and everything that was colourful becomes bright, but also with a hint of the dominant picture colour. Now it’s just a case of editing, transforming, distorting and adapting the frame’s shape to my perspective lines.