Trying to Watercolor Original Coastal Survey Prints

I bought a few original coastal survey prints on Ebay to see what it would feel like to watercolor directly on the old paper. The prints are beautiful, but the paper is extremely thin and already full of folds, soft edges, and even holes. Imagine getting 150 year old bible paper wet, then rubbing it between your fingers. That’s essentially what it felt like to watercolor this paper. There was a lot of “pilling” where little pill shapes of paper start to roll up under the brush. And where the paper was already torn the colors saturated poorly and it just looked muddy. I had to use more pigment so that I could get away with less water and protect the paper.

So far, I have only attempted on the Alden’s Rock print. I don’t want to risk ruining one of the more interesting prints until I’ve figured out the process. That said, I’m suspecting that the original print that captured my fascination might simply be digitally processed to add the color. If someone has an idea for how to analyze the image and test that, let me know via the contact page.