Some common cyanotype problems
Problem
What it looks like
Possible causes
possible solutions
Under exposed
Light blues, no details.

UV blocking glass
Damp or wet paper
Not enough UV exposure
Try a longer exposure without any glass.
Do a step test to find the correct exposure time.
Make sure coated paper is completely dry.
Over exposed
Image is too dark
All detail is lost

Too much UV exposure.
Try a shorter exposure time.
Blur
Blurry in some areas

Poor contact.
Bent backboard.
Bent Perspex.
movement during print.
Check for gaps between paper and artwork.
Detail loss
Whites are blue – Difficult to wash out

Over exposed.
Not opaque enough artwork.
Chemical degradation.
Reduce exposure time.
Check artwork density.
Chemicals should appear lime yellow/green on fresh coating.