I thought it would be interesting to see a line drawing and the same image after colouring together.
I used Photoshop after scanning in the original pen drawing, with at least 8 layers for :
Petals behind the figure
clothing & hair
petals front of the figure
Normally Colouring takes 4 times longer than B&W.
I didn't time properly, but I think I took about 3 - 4 hours in total.
I wish I can work much faster...!