Quote Originally Posted by Hologram View Post
Post-swelling the emulsion with sorbitol is probably a better solution than doing it with glycerin. But both may leave the surface somewhat tacky. Citric acid might be even more convenient.

Yes, "streak" may be a pretty good translation for Schlieren.
I have been thinking about the use of Citric Acid. This treatment might be harmful. IDK, but emulsions for the most part are at a neutral pH, say around 5.5 - 6.5. Citric Acid could begin to degrade the gelatin. Urea might be better for swelling the gelatin, if that is what you want. For an adhesive, Sorbitol, Glycerin, and other similar chemicals would probably be preferred.

The Schlieren observed is not Nebel, but streaks could be caused by fog and thus be stated that way in the original text as a description of fog (Nebel).

PE