printing for base density plus foggreenspun.com : LUSENET : B&W Photo - Film & Processing : One Thread
Anyone tried this? If so how reliable is this theory? Seems as though the exposure to the paper would be the same for ALL negatives of a particular film type. I shoot Delta 400. Here's what the article said...
1. Put the blank film in your negative carrier just as you would if it contained a negative. 2. Make a test strip by placing a piece of cardboard over your photo paper (leave one inch of paper exposed to the enlarger light) and expose for five seconds. Keep in mind that most photo papers REQUIRE an exposure of at least 20 seconds to achieve a full tonal range! 3. Move the cardboard to show another inch of paper and expose it for another five seconds. 4. Repeat #3 until you run out of paper. 5. Develop it fully.You should end up with a test strip that has exposures from 5 to 50 seconds.
Look carefully at the test strip. Follow the gradually darkening strips until you find the place where two stripes in a row are the same tone. This test strip indicates that the clear part of the negative will print black at 35 seconds. This should be the printing time you use for all the prints from this roll of film. Yes, I know it doesn't sound like it should work but here's how you do it: Set your print time for the blacks and use paper contrast grade to compensate for the whites. If, at 35 seconds (for this roll of film) your whites come out gray, use a higher contrast grade paper to compress the tonal range. If the whites blow out (print without any detail) use a lower contrast grade paper to expand the tonal range. This is how it is meant to happen. It's called printing for base density plus fog.
-- Joe Lacy (firstname.lastname@example.org), April 05, 2000
This relies upon having exposed the film correctly for your camera, lens, and lighting situation. It is a legitimate way to determine the correct base print exposure. In other words, it gives you the correct exposure for pure black--then you adjust development or paper grade until you get the high values where they need to be.
-- (email@example.com), April 05, 2000.
The theory is about right, though the statement about papers requiring 20 seconds is a bit misleading. They require a certain amount of exposure, and the time will depend on the intensity. There is nothing special about 20 seconds. Next, I suspect many very good prints never reach absolute maximum black, a somewhat overrated goal. No question though, if you want maximum black, you have to have the basic paper exposure to get there. You can apply the same rule to your contact sheets- if there is a tonal difference between the film base next to the sprocket holes, and the holes or area between the strips, you should increase your exposure. Personally, I find trying to reach absolute maximum black requires denser negatives that compromise tones, sharpness, or grain, in other areas of the print, but it's certainly determined by what effect you're after :-)
-- Conrad Hoffman (firstname.lastname@example.org), April 05, 2000.
You are getting the cart before the horse, you need to do the PEI (personal exposure index) test first to find your proper ISO/ASA for your equipment, then you need to do the Zone VIII print test on the paper you wish to use for the area which is brightest but still contains texture, and when you have established these then you will have establised maxium printable density. If you change any componet of the test you should retest, if you go from a grade 2 to a grade 3, you should do the print test again to establish Zone VIII print values. If you wish to understand what you are doing and how it work, get The Zone VI Workshop by Fred Picker, there are other's out there but his is the easiest that I have found to understand. Regards, Pat
-- pat j. krentz (email@example.com), April 05, 2000.
To simplify Pats post a bit - When printing, your exposure should be based on the minimum exposure necessary to record proper density (texture)in your highlights. A good rule of thumb is that you expose for your highlights and develop for the blacks.. In fact - if you are printing on the "correst" contrast ( the grade the negative is asking to be printed on) for the negative - your textured whites and your max blacks should be coming in at the same time on your test strips. If you are getting a tex. white before a max black ,you are to low in contrast. A max black before a tex white you are too high in contrast. Following this rule allows you to make corrections to your negatives to get them to the contrast grade you wish to be using.
-- jim megargee (firstname.lastname@example.org), April 05, 2000.
All of the information of a negative is between film base plus fog (fb+f) and max. density, and in an *optimally exposed and developed* negative, fb+f is pure black, and max. density is pure white. All you need to make this theory work is carefully calibrate your whole system. Then you more or less work according to the zone system. One problem when trying this with 35 mm or MF that there are many different photos on one film, usually with different lighting situations (some where the contrast between shadows and highlights is just a few stops, some where it's more than the film can handle). The other problem (with any format) ist that the film (and the human eye) can handle more contrast than the paper. So you might find that quite frequently, you have to sacrifice either the shadows or the highlights. There, the system breaks down.
That destructive comment given, use that method as a starting point. If the idea were nonsense, proof sheets would be useless, as each print would need its particular exposure.
-- Thomas Wollstein (email@example.com), April 06, 2000.