Quote Originally Posted by Ryuji View Post
I'm not sure about that explanation. Glass transition temperature of gelatin is only lowered by adding small amount of sorbitol. Plus, I did this experiment myself some time ago and srbitol-treated gelatin is permeable to oxygen and peroxide. If sorbitol treatment indeed prolonged the image longevity I suspect it did so via radical scavenging action on excited dye molecues, or perhaps by scavenging the offending molecule or its intermediate forms.
Glass transition temperature of gelatin is raised by adding sorbitol.

Permeability to oxygen was decreased and scavenging of free radicals was increased.

Results differ on RC and FB papers due to the permeability of the supports to oxygen, and the inherent ability of FB to absorb more of the sorbitol and change penetration from the back, or support side. This effect is also pH dependant.

The sorbitol stabilzers could not be used on RC papers very well due to blooming of the sticky sorbitol on the surface of the print. In fact, just about any stabilzer could cause problems when used with RC based color prints.

This is why the method of glass transition elevation was incorporated into the coating to improve dye stability of later versions of color paper.

PE