View Full Version : uprating 100 iso film

3-Jul-2007, 06:41

As you don't seem able to get readyloads or quickloads faster than iso 100, is it possible to uprate T-max 100 or Fuji Acros, and if so, what is the quality like on 4x5 negs? And recommended developers/times would be really helpful.

On a windy holiday in Scotland recently, I couldn't get a high enough shutter speed to stop blur in the trees or water.

I have a couple of DDS and some Kodak Tri-x pro 320, but I find loading and using them a real pain.

Many thanks for any advice.


Brian Ellis
3-Jul-2007, 07:32
Sure, you can rate the film at whatever you want. But assuming the manufacturer's rating of ISO 100 is the correct rating for you, if you rate the film at say 400 you'll gain two stops in shutter speed but be underexposing by two stops. The usual practice is to try to compensate for the underexposure by over-developing or "pushing" the film, i.e. developing for longer than your normal time. This will change the shape of the film's characteristic curve by increasing the density disproportionately in the highlight areas. In other words, you'll gain little if any density at the toe of the curve (i.e. the deeper shadow areas in the negative), a moderate amount of density in the midtones, and a large increase in the highlights. The overall effect will be to produce a negative with higher than normal contrast (and probably higher than normal grain).

You then can, of course, try to compensate for the increase in contrast (assuming you don't want an increase) by printing on a lower grade paper or using a lower contrast filter with variable contrast paper. But since the dark shadow areas of the negative have gained little if anything in density by increasing development time, and since you've underexposed the film by rating it two stops higher than its "correct" rating, you may lose desired detail in those areas as a result of your underexposure of the negative. OTOH, if the scene is one in which there is little or no important detail in the shadow areas then this procedure may work fine.

Without trying to preach to you, a better procedure would be to spend some time practicing your film holder loading technique so that you don't have to rely on Readyloads and can use film with "correct" rating for the situation. Most of us found loading film holders to be a pain at first as you have but with a little practice it can become almost automatic. I think it now takes me about a half hour to load 20 holders (40 sheets of film) whereas at first it seemed like it took a half hour to load one holder.

Bruce Watson
3-Jul-2007, 08:39
What Brian said.

Donald Qualls
3-Jul-2007, 12:01
In addition to what Brian said, it *is* possible to gain up to about one stop of true film speed with the right developers and techniques, without increasing contrast and with little increase in grain -- but you'll need to test your techniques to find out what you actually get with the combination of dilute developer, reduced agitation, and extended development time.

My own preference (being on a tight budget) is to use genuine ISO 400 film when I need the speed, in traditional film holders, and bite the bullet with regard to dust control. I buy high quality ISO 400 film, made in Europe, for about 1/4 the price of Quickloads or Readyloads, and with my standard development technique I can expose at EI 800 with very little reduction in image quality (Zone I exposure loses a little texture, dropping to a true Zone I on the negative instead of the Zone I 1/2 to II that I'm used to) -- and that's enough, even when I'm hand holding my Speed Graphic.

Chauncey Walden
3-Jul-2007, 12:04
Or, you can use a cumulative series of fast exposures like Paul Strand;-)