What exactly is this stuff?

http://www.freestylephoto.biz/sc_prod.php?cat_id=1004&pid=1000001606

"Fotospeed CSP100 Color Print Brightener and Stabilizer

"This unique chemical will brighten and whiten your color prints and can be used to improve previously processed material. It is designed to perform with RA4 and R3 color print material. Its stabilizing qualities will greatly increase the life of your prints by up to 40%. It can be used either after washing or in place of washing. Dilutes 1+9 to make the working solution."

Anyone tried it? What does it do? Is it a gimmick? I have seen it in their catalog for a very long time, but I don't personally know anyone who has used it.

It's usually a wetting agent, formaldehyde or other aldehyde type stabiser/hardener and an optica brightener. I have various formulae in the UK.

It works.

Ian

The problem is that the brighteners only work when UV light is present, and so the prints will shift in hue becoming more blue in daylight or UV rich light. Without UV light, brighteners are often yellow in color and they become more yellow as they keep in the dark. Therefore, prints with OBs have bluish tints in daylight, yellow tints in tungsten light and fade with orange whites over the years.

The only stabilzation is the absorption of UV if stored in bright daylight, or increased fungus and mold protection if stored in the dark.

If you want a good stabilzer use a dilute sorbitol solution of about 1% in buffered citric acid at pH 4.5 with about 1 g/l of benzoic acid. That would be better than the above. Warning here though. Although dye stability can be just about doubled, the prints are rendered slightly tacky due to the sorbitol. This solution is a very effective oxygen barrier layer.

PE