Film Questiongreenspun.com : LUSENET : Dirck Halstead : One Thread
First of all I'd like to thank Mr. Halstead for hosting such a fabulous site. It's really packed with some very interesting and useful information. Being a serious amature photographer who has only used reversal film, I'd like to start doing "available light" photography using black and white film. My question is which B & W film is recommended and at which ASA should it be shot? Tri-X or T-Max rated at 800 ASA? I'd like to know what film Diana Walker (featured in this issue) uses to capture her images in low light and at what ASA does she expose her film?
Thanks in Advance!
-- Frank Becsi (email@example.com), March 04, 1999
Push Tri-X two stops--ASA 1600 and develop in T-Max, or T-Max film at 1600 in T-Max developer. Can push the T-Max film to 3200 or 6400 also--depending on the shutter speed/aperature combo you have to work with. Don't know what Diana Walker used.
-- Judi Parks (firstname.lastname@example.org), March 04, 1999.
remember - pushing film affects the contrast (increases it) - one tends to lose shadow detail. To partially compensate for this one can use a so-called water bath - during development you pour the developer out of the tank (saving it!) and pour in plain water at the same temp for a minute or two (no agitation), then return the dev to the tank and continue developing as normal. The number of times one water-baths is up to you - experiment - every 3 or 5 mins depending on total dev time with whichever dev you are using is a good staring point. The time the water is in the tank is ADDED to the initial dev time (water is not a substitute for developer!). How this works is it allows the developer in the film emulsion to act on the activated silver halide molecules without being replenished from outside the emulsion. Areas of the film which have been more exposed (ie highlights) use more developer, and the dev in the emulsion in those areas gets used up quickly - in the shadow areas it gets used up slowly, and so acts longer/more in those areas, increasing the shadow-area density after it has stopped increasing in the highlights. This should give you richer shadow detail without blocking up your highlights.
In my experience Kodak TMax 3200 (TMZ) is overrated - it is extremely grainy, very susceptible to heat (store in a fridge!), and actually is only about 1000 ISO - ie when normally developed it only gives a vaguely normal tonal curve at this rating, not above. When rating at higher speeds you must use the dev time on the box for the rating one stop higher to get a good neg, in other words if you've exposed it at 3200, use the time for 6400. Ilford HP5+ gives better results when pushed to 3200 in my opinion (using ID 11 or Microphen). The ultra-fast film with the finest grain is still probably Fuji Neopan 1600, although based on heresay evidence the new Ilford Delta 3200 is almost as good. Kodak TMax is a great film for pushing when very carefully developed - slow agitation, experimentation and rigid adherence to times are vital for all TMax films, and they must be fixed twice as long as older emulsions (NB).
Note: Kodak D-76 is basically a marginally more potent version of Ilford ID 11. If you have a film dev time for D 76, but are using ID 11 in your darkroom, increase the dev time by about 15%.
Note 2: General rule of thumb when pushing film: increase dev time by 50% for each stop you've increased the rating by IN A COMPOUND FASHION. ie add 50 % to each successive time you work out, not 50% to the original "normal" time. A two-stop push will need a dev time 225% of the original, not 200%!
Adam Welz, Cape Town
-- Adam Welz (email@example.com), April 02, 1999.