Fotis
Here’s my question: what sort of results can I expect if, on the one hand, I develop a Tri-X or Portra (400) film—each exposed at the standard ISO 400—as if it were 800, and, on the other hand, I develop a Tri-X or Portra film—each exposed at ISO 800—using the standard development process? Thanks in advance for any advice.
TR
You control the shadow detail with the exposure time. You determine the contrast with the development time. If you expose a 400 ASA film in the same way as an 800 ASA film, you will always lose some shadow detail. If you develop a film (regardless of how it was exposed) for longer than would normally be the case, you increase the contrast or ruin the highlight detail. If you develop a film for a shorter time, you will still get sufficient shadow detail, but you’ll preserve the highlights. If you’re scanning your negatives, I’d always aim for ‘flatter’ negatives – you can always add contrast later.
If you use the camera’s built-in automatic exposure, be aware that you’ll be experiencing underexposure with a large proportion of your images anyway – meaning you’ll automatically be exposing your Tri-X at, say, ‘800 ASA’ without even realising it.
Fotis
OK, one more question about the second part of your answer: given the tendency for automatic mode to cause underexposure, would you recommend standard development for 400 ISO?
TR
The intensity of development always depends on the level of contrast you want to achieve. I would never develop for longer than the ‘normal’ time. Developing for longer does not compensate for underexposure! You can restore any lost contrast during the printing process or using a computer. However, if you consistently find yourself needing to work with higher contrast, it is advisable to develop the negatives for a little longer. Yes, in "normal circumstances" I would always develop "normally".
I expose the Tri-X at 320 ASA. For this, I use a handheld light meter and measure via a dome to gauge the light – so I can be sure that I am actually exposing the film exactly as I intend. Then I develop the film for as long as I can to achieve a gradient of 2.
If, for example, I were to expose a film only in mist, I would develop it for about 25% longer, as the subjects lack contrast and I can therefore ensure greater contrast during the negative development stage. If I only have subjects in bright sunlight, I reduce the development time accordingly. But here, everyone must determine their own values.
michael-kielgmxnet
One more thing about Portra: it can easily handle underexposure by one stop. There’s no need to adjust the development settings for this film; it’s developed using the C41 process anyway, and pushing or pulling is rather uncommon (though not impossible).
