Developing HELP?

Question:I shot a roll of iso 400 film two stops down. On top of that mistake, I took my light meter readings at iso 200. How should I go about developing?

Best Answer - Chosen by Asker: I shot a roll of iso 400 film two stops down. On top of that mistake, I took my light meter readings at iso 200. How should I go about developing?

Well,

I am assuming you are using black and white. just a guess.

400 speed films in most developers are about 200 in reality anyway, so the meter readings are out of the picture. Now, what you need is an N+2 (if you underexposed two stops.) I'm thinking that's what you mean by two stops down.

With a normal film like HP5 or TRI-X, you'll be pushing a couple stops to get something usable. These films don't mind at all, so for N+2, develop almost twice as long as you usually develop, and that will give you something usable, although contrasty.

With a T-Grain film Like Fuji ACROS, or Kodak TMX, you won't need nearly that kind of change. With TMX, 1.6 times as long as normal. With ACROS, 1.5 times as long should be right.

Hope you get something good.

Are you developing it yourself or taking it to be developed? If you're doing it yourself, what type of developer are you using and what brand of film was it?

You underexposed by two stops, but your meter readings had you overexpose by one stop. In essence you ended up underexposing by one stop.

So what to do? Well, there is a technical and practical answer.

The technical answer is that you need to push-process by extending your development time. How long to extend development depends on the film, developer and its temperature. Doing this would help pull out shadow detail, increase contrast but increase grain. The practical answer is to recognize that one stop underexposure is within the latitude of the film and to develop using normal development time--no pushing. Doing this might mean a little less detail in the shadows and the need to print on paper with more contrast.

If the situation in your question actually happened to you, then follow the practical answer. If your question comes from your homework or an exam, then it's hard to say whether your teacher wants the technical or practical answer. You would be the best judge of that.