Earlier I mentioned that I had experienced differences in exposure speed
between Brian's and B&S mixtures. This was based on a comparison of step
tablet results obtained from a fresh batch by Brian and a couple of month
old batch by B&S. I'm not sure that such a small difference of freshness
would be enough to cause a 20% speed difference. I can't find the step
tablet results for other papers that I've tested, but based on them I've
had to recalibrate speeds to much higher differences than 20%.
Yes, speed variation may come from changes in our equipment--I take it
that being a good detective is part of the trade. But I still believe
that mixture differences may well be the greatest source of exposure
variations. I'll be watching out for speed changes for Brian's mixture as
it ages.
Eric, I don't add anything to the B&S mixture. As to a ph test: I don't
have the necessary materials. An Sp Gr test? I don't know what that is.
And yes, Ginger as long as your kits were in powder form, they're still
good. Welcome to the wonderful world of Palladium!
Ron