the color darkroom
Join the war against fuzzy color prints: Use a focusing aid
I walked into the Bogen-Technical plant the other day and found myself confronted with a whole slew of grain-focuser-body castings. That came as quite a shock. I never expected to see grain focusers being manufactured in New Jersey. Osaka, sure—but New Jersey? It turns out that Bogen can domestically produce as good a product in Englewood, N.J., as the one they formerly imported, with fewer headaches, and at a lower cost.
Then there was the relic on Ed Meyers’ desk. He has what is probably the world’s first grain focuser sitting right in the midst of the usual pile of rubble which most editors affect. The minute I set foot in his office I spotted the thing, and was fascinated to find that he bought it second-hand about 25 years ago. Somehow I thought grain focusers were a lot newer idea than that.
A grain focuser is a simple little device that enables you to bring your enlarger lens to incredibly sharp focus. Typically, a grain focuser consists of a mirror (at a specific angle to, and some definite distance from, its base), a frame, and a tube containing an eyepiece and a reticle. The mirror reflects a tiny portion of the image you are trying to bring to focus on your easel, back up into the tube. The eyepiece, usually of between 10X and 20X magnifying power, allows your eye to focus on an aerial image of a small portion of the image your enlarger lens is projecting. The reticle is in the tube to give your eye a plane of reference at which to bring the aerial image to focus. The reticle is, most often, nothing more than.a piece of fine wire drawn across the tube or a circle etched into or painted onto a piece of clear glass or plastic within the tube. Most grain focusers have some mechanical means of allowing you to move the eyepiece optics toward or away from the reticle to accommodate your own particular eyesight. Before you use such a device on an enlarger easel, you first adjust the eyepiece so that it gives your eye a razor-sharp view of the reticle. Once you have made this adjustment and locked it (there is usually a means to do so provided), the grain focuser is ready for use.
You may wonder why I am discussing grain focusers in a column which has to do with color printing. After all, there are no silver particles in a color image, just transparent dyes. If there are no silver grains, what kind of grain is a grain focuser going to allow you to focus on?
About the simplest way I can answer this is to say that, when used
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to focus a color image, a grain focuser lets you focus on where the grain used to be. The dyes found in color negatives and in color slides didn’t get there magically. They got there by being formed in the immediate vicinity of metallic silver particles, which in turn got there by being struck by light, and then converted into metallic silver by the developing process. And that’s where the dyes came in. The dyes got formed wherever the developer acted on a silver-halide particle. Of course, once the dyes of a color image are formed, the silver and remaining silver halides are in the way. So we cleverly bleach and fix this valuable residue right out of the image and into our cash registers (if we happen to be large-volume processors), or down our drains if we don’t do enough processing to make silver recovery practical.
Since the dyes do not form uniformly throughout each dye layer of the image, it is possible to see tiny dye clouds, or puffs of dye, or “grain” in the image. You can easily see the “grain” in any of the faster color-slide films with nothing more than a small hand-held loupe of 5X to 8X magnifying power. Just think of how well this “grain” will show up when you project it from your enlarger lens at, let’s say 6X, and then observe a tiny portion of this projected image through a grain focuser’s eyepiece that provides you with another 15X of magnification. Effectively, you’re looking at a minute portion of the image at 90X under those circumstances; and at 90X there’s plenty of “grain” to look at.
While grain focusers are wondrous and, for the most part, inexpensive devices, and certainly belong on every color printer’s inventory list, they do have their limitations. The worst of these is that most such devices can’t be used very far off the optical axis
of the enlarger’s lens. For those of you who are not overly critical about your printing, this limitation need cause no tears. Just focus the center of the image and make your exposure. But, for the rest of us, not being able to tell if our corners are in focus when the center of the image is, this is more than the heart can bear. How will we ever know if the negative or slide in our glassless carrier has popped or not? How are we going to know if our negative stage is parallel to the lens board, and that they are both parallel to the easel? We won’t know unless we can find some way to critically check the focus way out in the corners and along the edges of the projected image.
Those of you with well-lined pockets can opt for a grain-focusing device with an incredibly long mirror, called the Micromega. Because the Micromega has a superlong mirror and a pivoting eyepiece, it is able to provide an image of the image at even the farthest corner of your easel. Such ability will cost you dear. The Micromega is a nice instrument, but its $99.50 price is anything but cheap.
Another way to focus on the edges is provided by those inventive Unicolor folks out in Dexter, Mi. They have an incredible-looking device called a Unicolor Mitchell Focusing Aid (which I will shorten to UMFA). This $14.95 piece of hardware looks like a kid’s plastic scale model of a droop-snooted supersonic airplane. It’s almost 14 in. long, and it won’t let you focus grain under any circumstances. That’s because it employs a groundglass screen (behind its mini-TV-like, low-powered magnifying lens) on which you focus your image. The grain of the screen will, of course, obliterate any grain you might otherwise be able to see in the focused image. But because of this device’s weird design, its incredible length, its awesome geometry, and its ugly pointy nose, you can get a good, screen-focused view of any portion of your image, right out into the corners. However, if the corners of your image don’t contain some very sharp, very contrasty lines (or other very fine detail), you will be out of luck, because there won’t be anything visible on the screen capable of being brought to sharp focus. Unicolor recommends that users of the UMFA shoot a black-and-white negative of a sheet of newspaper want-ads to use when aligning their enlargers. With such a negative the UMFA is a usable enlarger-alignment tool selling for a small fraction of the cost of a Micromega.
The other nice thing about the UMFA is that because it is so long it is convenient to use when making really huge wall or floor projections. You don’t need gorilla-length arms to reach the enlarger’s focusing knob, because the UMFA adds over a foot to your reach. But, for all its exotic virtues, this peculiar device still won’t let you focus on the “grain”; and that’s too bad, because, as far as I’m concerned, focusing on the grain is where it’s at—or, at least, where it used to be at. O