I'm relatively new in B&W photography and mostly use Ilford FP4 film which I found to be most pleasing. While enlarging I had determined the exposure of the paper to be 9s@f8.0 for a certain size and I developed the exposed paper in Ilford Bromophen stock solution. Recently I saw that the Ilford spec actually advised the stock solution to be diluted 1+3. Is this the correct way? Yesterday I prepared some developer as advised (1+3 from stock solution). However when I reprinted a negative with 9s@f8.0 and developed it in this diluted solution it turned out too light. I had an old print which was exposed for 9s@8.0 but developed in stock solution and I had to expose for 14s now to make an identical print. Is the developer concentration a parameter in the exposure of the paper? If not, what else can be the reason for the lengthened exposure? (Image size is the same) Best wishes, Omar

-- Omar Ozenir (omar.ozenir@turkcell.com.tr), November 11, 1998

Answers

Well, the "correct" way is the way that works best for you. But the usual way to find this is to start by following the instructions (including time and temperature), and then possibly vary them.

With concentrated temperature, you might find that the contrast of the prints is harder, as well as needing less exposure. And you'll get through the developer rather quickly. I suggest you get experience with 1+3.

-- Alan Gibson (Alan.Gibson@technologist.com), November 11, 1998.

Omar,

In my experience, whenever you change developers, you must start over and do new test strips to determine what the proper exposure is for processing in the new developer you are using. Basically, test strips for any negative are only valid for that particular printing session, using the same chemistry thoughout. You can not assume that the next day with, theoretically, the same set up, you will achieve the same results; the enlarging light bulb brightness may have changed with age, the water may be colder or warmer (although you should try to keep this consistent) or the developer may not be exactly the same mix. We try to keep things as consistent as possible, but performing new tests whenever a factor is changed is a good, paper-conserving thing to do.

Good luck,

Jon

-- Jon J. Eilenberg (jon.eilenberg@westgroup.com), November 12, 1998.

Thank you very much for the responses so far. I appreciate your help. I want to add a couple of things as to my procedure. A few months ago I listened to a small two hour lecture about B&W printing. The lecturer suggested the following to find "correct" exposure times: Insert an unexposed part of the developed film into the negative carrier (i.e. a part which has only film base + fog density). Make a test strip (with 1 sec. increments) and determine the time of the first full black (that after which no noticeable darkening occurs). This should be the "correct" exposure time for that particular film, development, enlarger height etc. Is this the right way to do things?

Thanks in advance, Omar

-- Omar Ozenir (omar.ozenir@turkcell.com.tr), November 13, 1998.

It seems like that method of doing test strips, which I have never heard of, assumes that you have PERFECTLY exposed negatives. I don't know about you, but although I strive to have perfectly exposed negatives, inevitably I end up with some thin and some dense. The density of the actual negative must be taken into consideration when determining exposure. With practice, I suppose you could determine exposure utilizing the method you describe and then make approximate adjustments depending on the density of the negative. Personally, I trust doing the tests on the actual negative with which I am working.

Jon

-- Jon J. Eilenberg (jon.eilenberg@westgroup.com), November 13, 1998.

Omar, you are describing the method of finding the minimum exposure that gives you the densest blacks. That is fine, but is only half the story. The other half is the whites. With this exposure, you may find that the whites come out grey (so you should increase the contrast), or you loose highlight details (so decrease the contrast). Changing contrast usually means you need a different exposure to get the maximum black.

And then you will find, as you become more experienced, that you can vary the exposure (and contrast) over different parts of the photo. But don't worry about that at the moment.

-- Alan Gibson (Alan.Gibson@technologist.com), November 13, 1998.