So I'm wondering, what's the difference between FRESH D76, and say, week-old D76? Has it oxidized? I'm switching to D76 from ID11. Maybe I should wait a bit after mixing before doing my calibrations.
Note: I'm not a chemist, nor do I play one on TV. My understanding is that oxidation is indeed the culprit but that's just from reading and talking to people. I have personally noticed a difference when developing Tmax-100 in freshly mixed D-76 vs. D-76 mixed a week before and stored in a 1/2 full gallon jug. The film developed in the old D-76 was at least a stop lower in contrast and had larger grain than the film developed in fresh D-76.
Mike
Politically, aerodynamically, and fashionably incorrect.
The MOD54 works well for what it does. I can do up to six sheets at once. It took me a little bit to get used to loading it but now it's pretty easy. I was unhappy at first that the sheets sometimes came loose in the processing. After a little experimentation I figured out that they came loose while pouring liquids OUT too quickly. I now just pour a little slower and it's working great.
It does what I need it too and is easier for me than trays at this point.
Tim
www.ScottPhoto.co
Mike Sherck's comments about "fresh D-76" have me bemused. It is well documented that D-76 gains activity in the few days after mixing. I have personal experience of this-getting horrible thin negatives from a batch mixed and used immediately. A week later,the same batch gave normal,predictable results. Go figure..
Neil,
ID-11 is for all practical purposes identical to D-76. You're only switching manufacturers, not developer.
Both D-76 and ID-11 have the documented characteristic of gaining a bit of activity after being stored for a while, so there will be a small difference in negatives developed with freshly-mixed D-76 and, say, week-old D-76. Normally, this difference is negligible, but noticeable. Most find it too small to worry about.
Best,
Doremus
In the "official" recipe for D76 the hydroquinone <SP?> isn't active and only the metol actually does the development. This is a result of the PH being to low. However after D76 is mixed the hydroquinone <SP?> reacts with the Sodium Sulphite and causes an increase in PH which is enough to make the hydroquinone active causing an increase in development. Unless you plan on using the D76 in a replenishment line it's best to simply eliminate the hydroquinone and increase the metol to 2.5gm per liter of stock.
It won't help with the drop off in activity over time resulting in oxidation but I mix it one liter at a time so that's never an issue for me.
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