Exposing Portra

[gevalia]

Guys,

I was given a "very" few 4x5 sheets of various portras today from someone that was going to throw them out. Before he left, I forgot to ask what if he used box speed or not and what range these negative films have.

So I did a little research and was wondering if you had any thoughts. Obviosly I would send these out for processing and since I have only 2 sheets of each in the boxes, I don't have enough for formal testing. Just a lets-see-what-we-get thing.

I have : 160NC, 160VC, and 400NC. None have expired yet and were fridged.

I figured I would try both 160's at 100 and the 400 at 200. Thoughts? I'm just venturing into color negatives (shot a little Velvia in April) and wondering about the range of these films. Do color negatives have the same range of B&W negs (say TMAX400)?

Also, looks like reciprocity comes into play after 10 seconds. Does anyone have a cheap sheet they work from?

Thanks,
Ron

[Bruce Watson]

I have : 160NC, 160VC, and 400NC. None have expired yet and were fridged.

I figured I would try both 160's at 100 and the 400 at 200. Thoughts? I'm just venturing into color negatives (shot a little Velvia in April) and wondering about the range of these films. Do color negatives have the same range of B&W negs (say TMAX400)?

I expose all the Portra films at box speed. Did the full Zone System testing for EI, using my local pro lab as processor, and that's what it came out. No big surprise there I suppose since the C-41 process is tightly standardized.

All over-exposing will do is generate more density, and increase the graininess of your highlights. Not really good things IMHO.

The portra negative films have surprising dynamic range. I've photographed scenes with subject brightness ranges of 11 stops or so with no ill effects like color shifting. OTOH I have had a few scenes that included some bright blue sky that generated enough exposure from the sky that it pushed toward cyan. The other colors were not effected, and it was easily corrected in printing.

They don't have the 20+ stops of dynamic range that the Tmax films reportedly have in the lab. But in real-world photography in the field they can handle just about any SBR you throw at them.

[Drew Wiley]

I use Portra sheet film frequently, always at box speed. These modern negative films are quite a bit different than the old Vericolor and so forth, which people routinely overexposed. Portra 160VC in particular has only a little more latitude than
the widest latitude chrome films, so isn't very forgiving of tinkering.