In the darkroom, should enlarger print exposures be made as long as possible?
Asked 10/18/2018
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2 answers
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When making darkroom prints, I wondered if it’s beneficial to aim for very long enlarger exposure times so any vibration from switching the enlarger on or off has less effect on the print. Possible ways to lengthen exposure would be stopping the enlarger lens down, increasing enlarger height, or using ND filtration.
But most examples I see use moderate exposure times rather than very long ones. Is there an ideal exposure range for printing, and what are the downsides of pushing exposure times as long as possible?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
7y ago
2 Answers
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Several comments on your idea:
- in an ideal setup you should have zero initial vibrations - the timer and enlarger are connected only electronically. Your pressing of a switch (or foot pedal in some cases) should not have any impact. If it does stabilize your enlarger - a good idea is fixing your center column to the wall.
- by setting too narrow aperture on your enlarger lens you are moving away from the sweet spot of maximal resolution (about f 8 for most enlarging lenses) towards dangerous diffraction territory.
- too long exposure times make for unproductive darkroom sessions
Most printers that I know aim for basic exposure times of ten to thirty seconds. Anything shorter than five seconds is risky because of reciprocity failure and unreliable meters (especially badly calibrated mechanical ones).
If you want to do any dodging and burning basic exposure of 20 seconds is about right for an 8×10" paper.
Short enough that you manage to have something done over your session and long enough that you can move your dodging tool smoothly enough from place to place.
Originally by user62463. Source · Licensed CC BY-SA 4.0
user62463
7y ago
0
Generated from our catalog & community — verify before relying on it.
No—there’s usually no benefit to making enlarger exposures as long as possible.
If vibration is affecting prints, the real fix is to stabilize the enlarger and use an electronic timer/switch setup. A properly mounted enlarger should not introduce meaningful shake.
Also, stopping the enlarger lens down too far is counterproductive: most enlarging lenses are sharpest around 2 stops down from wide open (often around f/8), and going much smaller can reduce sharpness because of diffraction. Some printers also refocus after stopping down because focus can shift slightly.
Very long exposures mainly slow down darkroom work. On the other hand, extremely short exposures are also undesirable, since they can be harder to control consistently and may run into reciprocity-related issues.
A practical target is often about 10–30 seconds for a base exposure. If your exposure is too short, use modest stopping down, ND filters, or a dimmer if appropriate—but don’t stop down all the way just to make the time longer.
So: aim for a stable enlarger, use the lens near its sharpness sweet spot, and choose a manageable exposure time rather than the longest possible one.
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