Quote Originally Posted by Photo Engineer View Post
Bill Troop and Steve Anchell have published the XTOL formula as stated in the patent, and the patent (according to Bill) matches the patent.
I discussed this with Bill just a few hours back.
PE
@Gerald: I did some searching a few months ago, and came up dry. Maybe I'll try again with archive.org or whatever it's called and see if they have it.

@PE: I weighed the two packets from my latest XTOL-purchase, and did some reverse-engineering to reconcile those measurements and the MSDS-ranges and the patent. My conclusion is that the sulfite was reduced slightly and redistributed, resulting in this:

Dry packet A:
Sodium sulfite ...................... 44.7 g (MSDS=44.9..)
DTPA ................................ 1 g (from patent)
Sodium metaborate (8 mol) ..... 4 g (from patent) (MSDS=2.6..5.2)
Dimezone S ..................... 0.2 g (from patent)
Total = 49.9

Dry packet B:
Sodium sulfite ................. 37.9 g (MSDS=37.4..40.05)
Sodium metabisulfite .......... 3.5 g (from patent) (MSDS=2.67..5.34g)
Sodium isoascorbate ........... 12 g (from patent) (MSDS=8.01..13.33g)
Total = 53.4

I'd also like to re-check this formula by mixing it and comparing pH's with XTOL, and comparing density-curves. But that will mean buying some DTPA, which I don't yet have. I'm suspicious because the pH in the patent is 8.20, but the latest and prior XTOL-batches I've purchased measured 8.29 and 8.26 with a calibrated meter. That makes me suspect the metabisulfite was reduced and/or metaborate was boosted.

Mark Overton