Van Dykes on craft paper

[VinceInMT]

On another thread,
https://www.photrio.com/forum/threads/cyanotype-issue-on-brown-craft-paper.183027/
I mentioned that coating cyanotype sensitizer on craft paper caused it to turn blue right away. I am doing some Van Dykes and, while I am generally using watercolor paper, I decided to see if the same issue occurred with Van Dykes sensitizer on craft paper. It doesn't.

Here are some samples. I did notice that the density of brown is not as intense as on watercolor paper but it could be related to exposure. I use the sun and yesterday we had none and the occasional skiff of snow.

I also noticed that applying cyanotype sensitizer to a finished Van Dyke will dissolve the Van Dyke image.

 

[revdoc]

Cyanotype sensitiser contains potassium ferricyanide, which bleaches silver images, especially images made of very small particles, like a VDB. Many reducers and bleaches (including Farmer's) use it as the main bleaching component.

That means you can print a VDB over a cyanotype, but not vice versa.