I have a question concerning the bw chromogenic films. I have heard that all chromogenic films have long exposure latitude. ASA400 -50-800, do I have to notify the lab in the case of push 1600 - 3200? Do they change the C-41 process?

Thanks

Jan Jedlicka Czech Republic

-- Jan Jedlicka (janjedlicka@atlas.cz), February 15, 2001

Answers

I'd get a 1-stop push in C41 for EI 800 from the chromogenics based on my experience, push-2 or push-3 for the higher speeds.

I tried an event at EI 800, no push with T400CN and it was not a success even with my condenser enlarger.

-- John O'Connell (boywonderiloveyou@hotmail.com), February 15, 2001.

Chromogenic films aren't much different than traditional films; there's lots of latitude for increase exposure and hardly any for underexposure.

A one-stop underexposure that's compensated for in printing by printing it on a higher-contrast paper gives a contrasty print that's lacking in shadow detail; a one-stop underexposure that's compensated for in development by extending development time so that it'll print on normal-contrast paper gives a contrast print that's lacking in shadow detail. There's really not a whole lot of difference. While you can certainly underexpose it three stops and develop it longer, the result will be a very contrasty, grainy print with detailless black shadows. In terms of overall quality, Kodak TMZ or Ilford Delta 3200 developed appropriately would be far superior.

To specifically answer your question, you can ask a lab to push the film, or extend the development. This isn't going to happen at a neighborhood minilab; you'll need to go to a professional/commercial lab that's willing to do it, and you'll need to be willing to pay the higher price for special processing.

-- John Hicks (jbh@magicnet.net), February 15, 2001.

I have had good results exposing Kodak T400CN at EI 200 through 1600 without any special instructions to the developing lab (I use a good pro lab). I have used the T400CN for indoor sports events at EI 1600 without special instructions to the lab and I have been pleasantly surprised with the results. One note of caution, though, is that I use the Zone system for exposing negatives and I tend to expose cautiously for shadow values with important shadows placed at Zone III or IV depending on the stuation (I use a Pentax digital spot meter and use my camera in manual mode). When used this way the negatives are thin but printable. If I were to use it at EI 3200 I would definitely have the roll push-processed. According to my understanding, the push processing simply involves longer processing times, just as it does for B&W processing.

As always, you should expose some test rolls under the conditions you expect to encounter to make sure you get the results you need. Try exposing two rolls at EI 1600 and ask to have one push-processed two stops. For EI 3200 why not try Ilford Delta 3200 - unless processing B&W is out of the question.

-- John McEwen (john.mcewen@sympatico.ca), March 03, 2001.