Newbie question. Getting ready to shoot my first LF 8x10. Using HP5 film. Most likely using Ilford Ilfotec HC developer. Reading about calibrating film and and using a Densitometer. Is this still necessary if I am using the same developer and Film? I don't have a densitometer and my head exploded when I tried to understand the process. I also have access to a 4x5 camera and HP5 film for testing.(cost) Is there a easier way to test? thanks
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Shoot some 4x5 first...
Tin Can
Kodak had a nice tip for evaluating your negatives.
Place your negative over top of a newspaper. If you can just read the type through the highlight area, and there is detail in you shadow area you pretty much have a good negative.
After 40 years of printing for others I still find this to be good advice.
Bob
Originally Posted by bob carnie
whatsa newspaper?
If you have access to a densitometer, then it's really not that hard to simple exposure/development tests. Fred Picker's Zone VI Workshop, probably available at your local library, lays out a good method, although he works in 1/2 stops, while I prefer 1/3 stops, as that mirrors available film speeds.
It's important to know that exposure has the greatest effect on darker areas of your scene. If you don't give enough exposure, they won't have any detail. Conversely, development time/temp/agitation affects the brighter areas of your scene more than the darker ones. As a result, you want to give your film enough exposure to get detail in your scenes darker areas, and you want to develop such that you have good tonal separation in your negative, and that the highest densities are appropriate for the medium you're going to print with. For instance, many alternative processes need more negative density than does printing on silver gelatin paper.
Assuming you're going to be taking landscape photos, and have a spot meter, do the following. Load some film holders. Set up a black mat card in shade, as you're gong to test film speed first. A standard black poster board works well. Meter the card, making sure that it is evenly lit. Make sure that there is nothing too bright in the background of the photo. Focus your camera on infinity, and aim it so that the card is in the center of the frame. You focus on infinity so that bellows extension doesn't affect the results. It doesn't matter that the card will be a little fuzzy. Set your meter reading for box speed, i.e. set it at ISO 100 for a 100 speed film. Measure the card. Let's say it gives f/8 at 1/60th of a second. Exposing at that setting would give a middle gray, known as Zone V in Zone System parlance. In this case, though, we're looking for Zone I, the lowest amount of light that'll still record well on the negative. To place the card on Zone I, you have to close down the aperture 4 stops, give 4 stops less exposure time, or a mixture. I prefer to work in aperture stops. Thus if the card reads f/8 at 1/60th with the meter, you'd set f/32 at 1/60th on your lens, placing the card on Zone I. Expose your negative. Now expose a couple more negatives opening the aperture by 1/3 stop each time.
Develop the film according to your best guess at the proper development. Read the film base + fog, the unexposed area of the film. Now read the densities of the card for each of the negatives. The negative shot at box speed will have the least density. You're looking for the negative that gives a Zone I density of at least .1 above film base plus fog. (That's traditional zone system practice. I prefer 0.15.) If the card shot with your first negative gives the proper density, then your film speed is what the manufacture says. Congratulations! That's not all that common. Usually the true film speed is about 1/2 of the advertised one. But if the desity is to low, move to the next negative, which should be slightly more dense. Since you gave 1/3 stop more exposure, this negative represents rating your film 1/3 stop slower than box speed. (So if box speed is 100, this negative would represent 80.) Keep reading negatives until you get the proper speed. Each one represent your film being 1/3 stop slower than the one before it.
Now you know your normal film speed. The next step is to fine tune your development time.
Set up a matte white card in sun. Meter the card. You want to place it on Zone VIII, a bright area with detail. Focus on infinity and take a meter reading, using the ISO setting that you determined in the earlier test. Setting the shutter at that setting would give a middle gray, Zone V. To get to Zone VIII, open up 3 stops from the meter reading. Expose 3 negatives at that setting. Now develop the sheet of film. If you're printing with a diffusion enlarger onto silver gelatin paper, you want a Zone VIII density to be about 1.3 above film base plus fog. If the negative density is to low, try developing another sheet for 20% more time. If the negative density is too high, develop for 20% less time. Use more sheets of film to narrow it down, if needed. After awhile, you'll get pretty good at guessing the proper development time from using one sheet of film.
You now have your Normal (N) film speed and development time.
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
Peter speaks the TRUTH! Using a light meter as a densitometer or a "visual densitometer" is a bunch of baloney. Fred Picker tried to come up with an intuitive method for most photographers (who are to lazy to do it right) and he offered to read negatives with a densitometer and return them with values. You can buy the Zone VI workshop used for $3.99 shipped. That's less than the cost of a single sheet of 8x10 film. But you do have to get off your computer and read it!
With 8x10 cost north of $5/sheet, you can waste all the film you can afford with your light meter or visual densitometer, but all you'll have is a bunch of wasted film or bad information which is worse than no information.
I follow Oliver Gagliani's methodology that he taught in his workshops in which he shot a "daylight" bulb behind a sheet of plexiglass. The front was masked with black paper, so you only had a bright circle in the center of even ilumination. You took a light reading of that area, set your shutter speed and aperture and then used ND filters to decrease the light instead of stopping the lens down as that is much more accurate. Then choose the ASA and developing time for a Zone I expose which was 0.15 density units over film base plus fog. That nailed your film speed and developing time.
Oliver was a pupil of Minor White and Ansel Adams and he attended the California School of fine Arts in the 1940's. He took up photography after loosing some of his hearing in the "big war" so he could no longer play the violin. After seeing a Paul Strand show, he was so impressed that he decided to become a photographer. I am fortunate to have several of Oliver's prints which I can always use as a frame of reference.
It's photographic sensitometry (aka science). Any other "easier systems" or short cuts are going to be flawed. It's just a matter of how good a negative you want to make, and how easily it will print. If you don't care, or you want to guess at it, go ahead. I'm sure the same "experts" who can't produce a printable negative will have all sorts of convoluted "techniques" to print them.
The last two X-Rite 301 densitometers sold on the 'bay for well under $200.00. That's two boxes of 8x10 Tri-X. You can run your tests using 4x5 film as long as the unexposed film base has the same density and fog, or you can cut down 8x10 sheets to make it last longer.
If someone wants to send me up to 5 LF negatives with a self addressed stamped envelope, I'll read them on an X-Rite 301 and return them. You can PM me for the address. I'll do this as long as it doesn't get out of hand.........
L
Olives's plan is pretty much what I will try to do today.
Test with DSLR for up to 10 stops in 1/2 steps with a known quantity studio strobe and diffusion.
I can then check density results in PS.
The strobe steps down very precisely, I check it all the time.
I made Pictorico step wedges with PS until I threw out the damned printer.
Tin Can
Luis, here's an fyi that I think is appropriate here. Years ago I queried Ilford about whether it's technically sensible to do film tests using 4x5 sheets and apply the results to larger sizes; here's an edited version of their response:
… all sizes of sheet film are cut out of the same master rolls, so the different formats you mention will have identical characteristics. … There can be small differences between 35mm, 120 and sheet film as these do use different bases and slightly different emulsions. …We endeavor to manufacture all three types to be as close as possible in order for development times to be consistent across the range for any one film type (and they are for most practical purposes).
Bottom line you will not need to duplicate your tests for 5x7 and 8x10.
Me too. You might find this article helpful: Testing B&W Film
Note that "almost everyone" who does rigorous film testing ends up shooting at one f/stop slower than box speed: 200 for HP5+ and TMY, 50 for FP4+ and TMX, etc. The more important issue is determining the development times which work for you.
If you don't care to load the Zone System into your brain, you might also find this even more helpful: A Simpler Approach. It's what I use after many decades.
And there is a simple reason for that, which almost nobody wants to know about, unfortunately. Suffice it to say if you plan on finding an EI using a Zone System-type test, you can skip that part and simply reduce film speed by 2/3 stop (or round it to either 1/2 stop of 1 stop).
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