View Full Version : 400 exposed as 100

27-May-2010, 18:03

Accidentally I exposed in a portrait assignment AGFA B&W 400 ASA as 100. What would be the best procedure now? Reduce only developing time? temperature? both? Do nothing and try to make up for that while printing? Thanks for any tips or considerations. Wagner

Gary Beasley
27-May-2010, 18:28
Depends on your lighting ratios. If extreme, pull the development maybe 20% (a stop) and print on low to normal contrast paper. If normal studio lighting then you might getby with no changes.

27-May-2010, 18:42
You can drop process the two stops, but you will probally have negs that are rather flat. I cannot remember the numbers to drop (or "pull"), try an internet search for "The Massive Developer Chart", and see what info you can get, I use it from time to time, and it is very useful.
I would suggest something like dropping 1 or 1 1/3 stops, and then compensate for the rest in the printing, so that the negs aren't too flat, and not too heavy, but that depends on the lighting you were using, and if your metering was correct.
The best way, if you have some test shots and can afford to run a test, try processing at a time/temp of your choice and see how it looks, and then do the rest based on that, but only if you are confident that your exposures are consistent.
If you do choose to drop by a full two stops, you might get uneven development, so lower your processing temp a couple of degrees, so that your total time isn't too short, also, but take that into account when calculating the time, of course!
You will likely get many other opinions, but I hope this helps!

Ben Syverson
27-May-2010, 18:46
It depends how contrasty your lighting / environment is... I normally rate negative film a stop slower, so this sounds like only a 1 stop error to me. You might not even notice a difference!

Jay DeFehr
27-May-2010, 19:10

Since it was a portrait, I assume the lighting was controlled/ moderate to low contrast. You've over exposed by 2 stops +/-. This is going to produce a dense negative. If you also give the negative less than normal development, you'll get a dense and flat negative. Not a great scenario, but I think it's your best alternative. If you develop normally, you'l have a dense, grainy, coarse negative to print on grade 2 paper. If you reduce development, your negative will be flat and dense, but not AS dense, and it won't be as grainy, and you can make up for the low contrast negative by printing on a higher grade of paper, preserving the local contrast in the mid tones. The worst case scenario is a dense, high contrast negative that requires a low grade of paper, thereby destroying the fine separation tones. I think the best case is just the opposite of what you have; a slightly underexposed/ overdeveloped negative. You might try an ultrafine grain developer, like Microdol X, that loses a stop of speed, to get you a little closer to correct exposure. Good luck!

Brian Ellis
27-May-2010, 19:40
You've overexposed by two stops (even if you rate negative film a stop slow as someone else mentioned, you've still overexposed by two stops not one since your 400 would have been rated at 200 and your 100 would have been rated at 50).Two stops overexposure with b&w film isn't that big a deal. You can bring a two stop overexposure down to something close to normal with N minus 2 development. Assuming you haven't done any zone system testing and so don't know your N minus 2 time, reducing your time by about 25% should get you in the ballpark. The negative won't be that flat since the darker areas will be fully developed even at a reduced development time and to the extent they are flat you can control that in printing.

27-May-2010, 21:52
I usually over expose my portraits by 1.5-2 stops. I develop using rodinal 1:100 at 17degC for 12mn with constant agitation. Thats my recipe for b&w.
Again, you might need normal dev time because of below draw in tight head shots.