We see repeated "D-76 rises in pH as it ages."

However, packaged D-76 is buffered, therefore should not. Anyone have a pH meter and want to shoot down this myth? I'm referring only to packaged D-76, not homemmade.

-- John Hicks (jbh@magicnet.net), June 22, 2001

Answers

In reading a paper by John Sexton about T-Max films he states"If you use D-76 developer be sure to use FRESH D-76 (not some that has been sitting around in a half full bottle for a month!) As D-76 ages a chemical compound, hydroquinone monosulfonate, is formed. This chemical compund will INCREASE the activity of the developer and the contrast of your negatives in a big way with T-Max." I wonder if this is not the increased activity that is being attributed to a rise in pH?

-- Jeff White (jeff@jeffsphotos.com), June 23, 2001.

> As D-76 ages a chemical compound, hydroquinone monosulfonate, is formed. This chemical compund will INCREASE the activity of the developer and the contrast of your negatives in a big way with T-Max." I wonder if this is not the increased activity that is being attributed to a rise in pH?

Could be; I'm not a chemist and certainly don't know.

I've seen it explained that the rise in pH activates the hydroquinone, which at normal pH simply regenerates the metol. Grant Haist proposed a simple solution to the problem by eliminating the hydroquinone and slightly increasing the metol, to make D-76H.

But what I'm really getting at is that this is taking on the characteristics of a myth, similar to "fixer sinks to the bottom," with people simply repeating it as common wisdom...and it might not be true.

I'm not questioning the change in activity associated with D-76 mixed according to the formula; that's well-documented. What I'm questioning is the common wisdom that _packaged_ D-76 increases activity with age, given that the packaged version is _not_ plain old D-76. I've never seen anyone make any distinction between the packaged version and the formula version while making the assertion.

The obvious test would be for someone to make up some packaged D-76 and test it, say monthly, with film exposed to a step wedge and the resulting densities logged.

-- John Hicks (jbh@magicnet.net), June 23, 2001.

The latest issue of Phototechniques has an article examining the effects of age on developer activity. Reports the tests of a number of developers including D76. Unfortunately, the primary question was related to developer exhaustion and I don't think the pH was measured - also I'm forgetting how long the developer was tested but it may not have been long enought to allow for the rise in pH. If memory serves me right, D76 did exhibit an increase in activity, unlike most other developers that showed a decline. Might make for interesting reading if you haven't already seen it. Cheers, DJ.

-- N Dhananjay (ndhanu@umich.edu), June 23, 2001.

i guess my one data point is better than none, anyway i can easily check my d76 pH but unfortunately i didn't check it when first made so that wouldn't tell very much (i've seen our water here jump around from 5.5-6.7)

as for increasing activity, i should know soon... i just developed a couple rolls with some 4 month old d76 and this time i cooled it down to 20 oC so i can compare to past results, i can verify that 4 month old d76 at 24 oC is much more grainy with slightly more contrast than fresh d76 at 20 oC..... i'll be printing some of the 4 month/20 oC negs this week and i'll post comparisons

joe

-- Joe Holcombe (joe1013_@excite.com), June 25, 2001.