Light meter battery ran low and I overexposed my ASA 400 HP5+. How much should I push my film?

Question

Equipment: HP5+ 400 ASA, Rollei 35

Light conditions and subject: Sunbather in grass surrounded by trees but with Sun in clouds fairly overhead, sometimes in some shadow. Bright day but with sky covered by white cloud (clouds acting like big diffuser). I'd estimate an EV between 11 and 13.

What I did: I was an idiot. Light meter showed that for 1/125 seconds I should use around f4. Sometimes it went below that to f3.5 and no higher than f5 when I dropped to 1/60 seconds. I consistently shot what the light meter recommended (only afterwards did I think that it didn't seem right for the conditions and changed the battery).

In terms of EV values I think I exposed for 9 when it should have been 11, and exposed for about 10, when it should have been 12-13.

Questions: Should I push my film? If I do, how much more grain am I likely to get?

Any other experiences, thoughts and advice are much appreciated!

Edit: I've realised that in effect what I did was pull my film from 400 to 50. Maybe someone has tried this before?

Answer 1

If you've overexposed, you want to pull rather than push your film.

Film pushing involves developing to higher than normal contrast, which causes a given exposure to produce more density. Since this is proportional to exposure, exposures barely recordable move up to low-mid tones, middle exposures move up to high-mid, and highlight level exposures "block up" -- becoming too dense to print by the old optical, silver-gelatin methods.

In your case, with film that has received a bunch of extra light, you need to do the opposite. By developing less than usual, you'll keep your overexposed highlights from blocking up, and preserve your ability to print or scan negatives that would otherwise be too dense.

In fact, what you did (exposing by two extra EV over what should have been correct) is often done intentionally by photographers, in order to obtain good shadow detail, with reduced development then applied to tame the highlights.

Fortunately, there are published developing times for HP5+ at EI ranging from 100 (which is about what you actually gave) up to 1600 or more. Just look up the correct time for your chosen developer for HP5+ at EI 100, and develop that way -- you may find you like the result enough to do it intentionally on a regular basis.

Answer 2

When people say they "push" their film, what they almost always mean is that they "pulled" exposure (i.e. underexposed) and as a result the film needs to be "push processed".

Since you "pushed" exposure, you need pull processing to compensate. That is, if you think you overexposed by about two stops, then under develop by about two stops.

For more, please see:
Overexposing and pushing in a roll of film, can they compensate each other?
What kind of appearance can I expect if I both overexpose and push film?
Overexpose film in camera, then push process?
If I push film can I keep all other settings such as aperture and shutter speed the same or do I have to change them as well in some way?

Answer 3

ISO 100 (EV9/EV11;EV10/EV12) is w/in the exposure latitude of HP5 (many rate it at ISO 200 normally), you don't really need to adjust the developing time at all (you'll just get higher contrast results)... but if you decide to, I wouldn't go much more than 1 stop.