Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 beta 3/9/83; site tellab1.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxl!ihnp4!tellab1!rcl From: rcl@tellab1.UUCP (Ron Lewen) Newsgroups: net.rec.photo Subject: Re: sharpness (Longer than I had intended) Message-ID: <196@tellab1.UUCP> Date: Thu, 24-May-84 16:25:33 EDT Article-I.D.: tellab1.196 Posted: Thu May 24 16:25:33 1984 Date-Received: Wed, 30-May-84 08:58:56 EDT References: dartvax.1647, <282@wxlvax.UUCP> Organization: Tellabs, Inc., Lisle, Ill. Lines: 129 One thing most people tend to neglect when the attempt to achieve maximum sharpness is the processing. All of the suggestions I have read so far have been good ones, and they should be followed (to what extent is up to you), but after all this is done, you can wipe a lot of it out in the darkroom (I am mainly talking about B/W. I am not as familiar with color processing). 1. Film Developer The first contributor to mushy prints is the film developer. I learned long ago to stay away from "fine grain developers" like Kodak's Microdol-X. These developers contain a solvent that "eats" the edge of the silver-halide crystals in the film. This, as intended, reduces the visibility of the grain in the final print, but think about what it can do to sharpness! An easy experiment can be performed by shooting a roll of 12 exposure film (use your usual) of the same, or similar, scenes. Take this roll, and develop half of it in Microdol-X (or any other "fine-grain developer", and develop the other half in a "normal" developer (HC-110 is one, if my memory still works). Then print these negs at the same exposure, aperture, enlarger head height, etc., develop them at the same temperature and time, and then compare the grain. Use at least an 8X10 print, and a decent magnifier. 2. Processing time, temp, handling, etc. Another key to sharp negatives is how they are handled during processing. Processing time should be monitored accurately, and an effort should be made to keep a log of the best processing time for rolls shot outdoors on sunny days, outdoors on cloudy days, indoors under existing light, indoors with flash and so on. Keeping a roll of film in the developer too long will not only produce an overdeveloped neg, but will reduce sharpness due to the "eating effect" (this will happen with normal developers, but to a much lesser extent than with "fine grain developers". Processing temperature can have a big effect on sharpness, and not only absolute temp, but relative temp. Absolute temp effects sharpness in that the film will be in the developer longer at lower processing temps. Sharpness will not be lost here because of the "eating effect", but simply because the film will have a chance to soak up more moisture (and chemicals), and will experience more shrinkage and curling during drying. Wet time for the film should be as short as possible (without sacrificing "archival" quality, i.e., the ideal of total removal of chemical residue from the negs, but that is another discussion). Since I mentioned shrinkage, lets talk about relative temperatures and their effects on sharpness. Consider a roll of film developed at 75 F for 7 minutes. At the end of this 7 minutes, the film has pretty much reach an equilibrium with the water, and is close to 75 F. Now lets dump out the developer and pour in a stop bath (or water if you chose) at 82 F. This sudden change in temperature is going to cause the surface of the film to expand slightly. Since the warmer stop doesn't reach every spot on the roll at the same time, the surface of the film reacts differently at various location. Now lets throw in a fixer at 77 F, throw it into a water bath at 68 F and dry it at 72 F. That poor film is expanding and contracting so many times, and in so many directions, it's a wonder it can get back close to normal! Well, maybe I exaggerate a little. But seriously, the film does expand and contract with temperature changes, and when drying, and these motions, however small, can distort the image. This distortion may not be noticeable without a microscope, but when you want to make mural size prints, even the slightest aberration can show up. 3. The printing process This could be the weakest link in the whole darkroom. How many amateur photogs bother to use a grain focuser when printing? If you do, do you place an old sheet of paper of the same type you will be printing on under the focuser? Think about it. It makes sense that if you are going to go through all the other steps listed above, and in other articles, you may as well take the time to focus the enlarger as accurately as possible. This is where the old piece of paper comes in. With the grain focuser, you are actually focusing on the grain in the film. If you set the focuser on the easel directly, you will have focused the enlarger for a spot a full paper thickness below the actual printing surface (the surface of the paper). With the focuser on a piece of the same paper, you are focusing on the printing surface, and will achieve greater sharpness. What about the enlarger itself? Keeping the lens clean will help, as will cleaning the condensers (if your enlarger has them). Also clean the neg carrier if it has glass. Speaking of neg carriers, make sure that the neg is flat! Nothing is worse than to spend the time required to make a print only to realize that the spot you used to focus on was the lowest spot on the neg! (on this note, check the focus at several points to be safe.) In addition, let the neg warm up before you focus! If you focus with a cold (or cool) neg, and it buckles as it warms up, the print will be out of focus! 4. The enlarging lens When you buy a new lens for your camera, do you buy the cheapest lens available, thinking that a lens is a lens, and no one will ever know the difference? Probably not. So why do the same for your enlarger? There are some excellent quality enlarging lenses on the market, and they really aren't that expensive (you can, however, spend several hundred dollars if you really try!). Buy a good lens! Again, if you are really serious about sharpness, the enlarging lens is as important as the camera lens, and maybe even more so. For 35mm negs, I use a 50mm Nikkor-E (I think... My memory is slipping as of late), and for 4X5 negs, I use a 150mm (again, I think) Rodenstock Rodagon (or something close to that). I really like the Rodenstock. It even has a little lightpipe that lights up the aperture dial so you can see what you are doing (the lightpipe is safelight orange, of course). The same comment made about the aperture of your camera lens holds for enlarger lenses; use an aperture setting about midrange for the lens. And...As mentioned above, KEEP IT CLEAN! Dust is one thing, but never get finger prints on any lens. Human skin oils have a nasty habit of eating into the coatings on photographic lenses, and a neglected finger print can ruin a lens. Well, I have rambled on long enough. I hope that I have said at least one thing that will help. Comments? Questions? Mail them to me. Flames? Mail them to /dev/null, my fragile ego can't handle them! By the way, if you have a couple of scenes that you would like mural size prints of, and are really interested in sharpness, try renting a 4X5 (or larger) view camera. You will probably have to enlist the help of a friend with a good back to help carry the equipment, but the results are worth it. I have a couple of 40X50 inch murals I printed (in my own darkroom, but that, too is another article) that came out just beautiful (pat pat pat... I hope I don't hurt my shoulder reaching around to my back like this). If you don't know how to use a view camera, there is bound to be someone in the local camera shops or clubs that will be willing to help. If not, any school that has a decent photo department should have classes (and the school may have equipment you can use!). -- Ron Lewen ....ihnp4!tellab1!rcl <---------------------------------------------------------------->