D-76 pH rise?

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

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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.

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?

> 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?

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

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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.

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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.

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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.

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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.

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.

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)

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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

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joe