The chart below might surprise you if you’re tray developer.
From a related thread, Steve Gledhill’s chart shows a significant increase in temperature of the developer solution (800 ml) during tray development – more specifically, a 2.5° C jump after 7 minutes, and a 4º C jump after 15 minutes. These changes are typically due, I suspect, to a combination of using the hands; the air temperature (if warm enough); and the heat-producing chemical reaction itself.
Put more simply – it shows the developer solution’s average temperature is significantly higher at the end of the development step, than it was at the beginning.
So that leads me to a few questions…
1) Do you account for such changes when you “choose” a development temperature? Or, do you simply repeat the process that gives satisfactory results, and worry less than others about possible temperature changes?
2) If you use a technique to keep temperatures constant (such as rubber gloves, slosher trays, water baths, etc.), have you actually tested the effectiveness?
3) And, if your darkroom’s air temperature is different from session to session (say, winter vs. summer), might this influence the “slope” of the developer’s temperature line (for example, steepen it), causing inconsistent results & splitting headaches?
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What’s your personal experience? Can you share tips or insights about this?
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