Developing observation drawings on Photoshop

Inspired by how Olivier Kugler draws and then later adds colour digitally I wanted to try adding colour to my drawings on Photoshop. These are just some quick (and not very neat) experiments at doing this.

Morrisons cafe drawings. I think using a few select colours really brings out the atmosphere. But having large areas of strong colour can look a bit oppressive. I've noticed Kugler generally tends to stick to adding colour to smaller details. I should probably look at doing this.

 Vintage London bus. I think leaving the white negative space areas works well as it stops it from looking too much. I like the black accents as well as they seem to add depth.

For this one rather than Kugler I was inspired by Sami Kronk and her drawing in white on a coloured background. I think it looks okay but messing around with the colours has had a negative impact on the line quality.