paper matters

The one variable that strikes fear into the hearts of those of us working with hand applied, light sensitive emulsions: paper types and paper pH. With a delicate, hard to harvest and distill emulsion like the purple flowers I am discovering that paper matters.

I've been noticing that the flower petal emulsion seems a bit faint and much bluer than I expected. I've come across references to flower pigments yielding surprise colors with no reason. I suspect that the pH of the paper is the culprit.

The picture above has four paper types.

1. The paper on the bottom is the Fabriano Aritstico Hot Press Extra White. It worked great for the Pokeberry juice but the emulsion seems faint when brushing on. I ended up putting three coats on it and got what Bridgette thinks is a nice blue. Thanks Bridgette and Jill for the suggestion.
2. The next paper is a light weight Kozo paper from Bostick and Sullivan. It was labeled E on their old sampler pack which was a freebie a few years back!
3. On top of that is a square of Arches Platine, a favorite paper of platinum palladium printers.
4. On top of everything is a strip of my favorite Kozo Unryu (the backside). Surprise... it looks the best!

BTW, the happy accident also contributed to this report. I was using the Kozo Unryu as a means of wiping off the organic debris from my brush and noticed that it looked purple and the purple seemed stronger than the blue that was applied in one coat to the Fabriano. I don't know the pH of the Kozo Unryu but I do know the Kozo light weight and Arches Platine work well with iron (siderotype) processes because of their neutral to slightly acidic pH.

I remember from undergraduate biochemistry the role of pH on the 3-D structure of proteins. During the last few weeks  also discovered that heating plant pigments to "reduce" them is not a good idea. I lost the rich magenta color of pokeberrry doing this very thing. Changing the shape of the protein via heat  or pH may change its color.