Main Motorcycle: 71 T100R
Join Date: Nov 2008
Location: Nebraska, USA
I've asked the same question and have done a little research off and on over the last couple of years to try to find the holy grail of brighteners.
Most commercial operations use chemistries with proprietary brighteners, so it's a trade secret what they are.
Another route is to look at some of the patents for brighteners. This is more fruitful, but still fairly useless, since most of these are pretty exotic chemicals that don't show up in traditional lab chemical suppliers' catalogs.
Of the few I've found in patents or elsewhere that can be gotten from lab suppliers, mostly the price has just been too high to take the plunge.
There are some fairly simple substances, however, that come down through plating lore. Among them:
Various sugars (glucose, sucrose, dextrose)
EDTA (This is sold as a health supplement, but it's usually not in pure form)
If I ever get more leisure time, I'd like to experiment more, but for now the gelatin gives me predictable results. There is very little of it in my bath (less than 2 grams/gal), so I haven't noticed the stickiness problem.
For only a little more, you can do it yourself!