Charles Dias <charlesbronsondias@hotmail.com> wrote/replied to: > Today a friend of mine asked something I couldnīt answer ... he said: > > "Ok, I understand the advantages of pushing up a film to a ISO higher than >itīs nominal rating ... but what is the advantages of doing the contrary, >pushing the film down to a ISO lower than itīs nominal rating???" > I sometime push Neopan 400 to ISO 200 to get a fine grain or do the same >with other film to get more contrast ... but I guess there are another >advantages I donīt know too ... anybody can help us??? You can underdevelop black and white by under rating a film, and you can get finer grain, but you will likely lose some shadow area development that happens near the end of development. Remember, film development has a natural tendancy for areas to slow down in development as the density builds in highlight areas, development slows down. In the shadow areas, they keep on developing. True, more exposure in the shadows does help, but only to the point where exposure is too weak. Sometimes shadows tend to be very dark, a couple of stops more exposure often makes a minimum of difference in details gained. Meter it and know. And, in my experience gaining shadow detail means longer development, but without blowing out highlights, this can only happen well when exposure for highlights is controlled. (not by under rating) I under rated a negative film lately, cause I wanted more light on the subject's faces, well lit eyes, etc. And, well I wanted to see what would happen. I'd read about the huge latitude of neg films. I was disappointed with the results. I lost highlights, no matter how the film was scanned or printed. This was at one stop overexposure! There is the likelihood that I would have lost highlights in those shots even at normal exposure, but I might have retained enough to make the photos better. The fill flash worked nicely, but the main light, the sun was too strong. Needed assistant with diffuser :-) Areas of low exposure need more time, but keep their level of activity throughout the film processing. When you lose shadow and some midtones, your apparent contrast increases as your actual tonal range compresses. Personally, I think the highlights in a photo are usually most important, and the overall contrast dictates whether under rating a film is possible. Especially in slides where when you lose highlights, they're just clear film. People say they get more saturation on a slide by under rating. Conditions and lighting need to be controlled even more than usual to hold your highlights. Overall, your saturation and apparent contrast increases. In all likelihood, you're now shooting more for the shadows than highlights by under rating a film. If you can get your lighting range to where you want it, you can under rate and see the difference. It depends what you're shooting, etc. Only one way to find out though - try a roll under rated see what happens. "take every day as a gift, never get angry at the idiotic mass of humanity, delight in the craftsmanship of BMW and nature" Jim Davis, 2002
