I've been thinking of something similar to display calotypes, which are often very beautiful viewed by transmitted light. Similar worry... not sure if it would be good for them in the long run. But maybe for a short term gallery display.
You have overlooked that I posted the Google-translation page, from which one cannnot download. But of course you can call-up the original site, which URL is given prominently at the Google page and load down the pricelist from there.