I have been experimenting trying to achieve the lovely blue tones you see in cyanotypes. I don’t have access to very sophisticated photo editing software so my efforts are a bit limited but they will give you an idea of what can be achieved.
Convert your chosen photo to a negative and then experiment with the hue saturation and lightness settings.
This is the basic photo with well-defined edges and good contrast colourwise
Here is the same picture negativised
Unfortunately I couldn’t achieve exactly the effect I wanted but it was quite close. However, I did chance upon this one, which I really like.
It’s all a question of experimenting.
More information and some stunning artwork by Lou McCulloch can be seen here.
If you don’t have a camera, worry not. The same sort of effect can be achieved by using rubber stamps and dark blue ink.
The effect is achieved by spreading blue ink or paint on your chosen support (I used Bristol cards, which have a slightly satiny finish which takes the ink and the stamped image very well). Allow the colour to dry. Tamp your rubber stamp gently on some dampened kitchen paper to which you have added a few drops of bleach. Stamp your stamp on to the colour and watch as the colour leaches away leaving the image in white.