Rating 400 film at 200 and underexposing ...

bessa_L_R3a · May 26, 2008

Hi,

I asked a photography student friend what would happen if I shot 400 ISO BW film but rated the camera at 200. He said that would overexpose the film by one stop (with normal development at 400). I developed the negs and sure enough, the whites were REALLY white ... too much.

So I thought, what if I left the speed dial at 200, but set the exposure compensation dial at -1 shooting on aperture priority.

So on the one hand, I am overexposing, but the -1 exposure compensation underexposes, so am I actually just adding and subtracting and accomplishing nothing with this?

R.

David A. Goldfarb · May 26, 2008

bessa_L_R3a said:
So on the one hand, I am overexposing, but the -1 exposure compensation underexposes, so am I actually just adding and subtracting and accomplishing nothing with this?

R.

Yes.

If you get better results at the box speed in the developer you are using, then shoot at the box speed. If you don't see enough shadow detail, then use a lower ISO setting. If you have good shadow detail on your negs, but your highlights are blown on the prints, then reduce development time. If your shadow detail is good, but your highlights are flat, then increase development time.

David William White · May 26, 2008

Correct. And rate at 100 is cancelled out by -2, etc.

The exposure compensation +/- is to quickly fool aperture priority for INDIVIDUAL frames of a roll, i.e. your subject is backlit and you need to bring them out with +2.

k_jupiter · May 27, 2008

Now... you have it explained that by adjusting the exposure on your camera, you have brought the film speed back up to where you started...

My whole portfolio in photography school was shot on Tri-X @ 200, developed in D-76 1:3 continuous random agitation at 25% reduction of the Kodak Tri-X 400 EI 200 times. Got it? Instead of 8 minutes at 68deg, I developed for 6 minutes at 68deg. The small (135 double roll)tank was never put down, it was rolled, flipped, inverted, swung in huge arcs, and whatever for the entire 6 minutes.

What it got me was extremely printable negatives on Grade 2 paper with wonderful shadow detail, and easily controlled highlights.
I didn't figure it out overnight and I suspect you will not either.

tim in san jose

c6h6o3 · May 27, 2008

bessa_L_R3a said:
Hi,

I asked a photography student friend what would happen if I shot 400 ISO BW film but rated the camera at 200. He said that would overexpose the film by one stop (with normal development at 400). I developed the negs and sure enough, the whites were REALLY white ... too much.

It's the shadows you should be looking at when trying to determine film speed. Get those right first and then adjust your development time to bring in the highlights.

Ian Grant · May 27, 2008

You need to do your own film speed tests, many of us use 400 ISO films at lower speeds to achieve the best balance of tonality. Personally I always use Tmax400 @ 200 ISO and get excellent results. But I've also set my own developing times which match what I'm aiming to achieve.

It's really up to you to see what works best for your photography.

Ian

vdonovan · May 27, 2008

I lOVE Tri-X exposed at E.I. 200. Developed in Xtol 1:2 for 8 minutes.

David William White · May 27, 2008

superb

bessa_L_R3a · May 27, 2008

David A. Goldfarb said:
Yes.

If you don't see enough shadow detail, then use a lower ISO setting. If you have good shadow detail on your negs, but your highlights are blown on the prints, then reduce development time. If your shadow detail is good, but your highlights are flat, then increase development time.

what I am trying to avoid is whites that come out looking gray or off white, and blacks that don´t really look all that black ... I will post an example soon. gotta run to work (a job that doesn´t involve photography ..

Rolleiflexible · May 27, 2008

bessa_L_R3a said:
what I am trying to avoid is whites that come out looking gray or off white, and blacks that don´t really look all that black.

This is not likely a function of EI or processing, but,
rather, your interpretation of the negative in the
scanner or the enlarger. You need more contrast.
Adjust your scanner curves, or use a paper with
higher contrast.

RFXB

Rating 400 film at 200 and underexposing ...

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