This week's column by Ctein
I frequently describe dye transfer printing as being a little like having Photoshop in the darkroom. For a complete description of the process, as I use it, please read this article. Because I'm dealing with individual separations, I can control the characteristics of each primary color component of the print—think "channels" in Photoshop. This lets me do things that would be impossible with conventional color printing. It also makes some kinds of controls trickier.
My photograph of Castle Eilean Donan, one of the four images Mike and I offered in the final blowout dye transfer sale on Wednesday, has several problems as a "straight" print. First, the light in the foreground and in the sky was considerably brighter than the light on the castle, so the print needs dodging and burning in if it's going to look good. (In my experience, most photographs can be improved by judicious dodging and burning-in.)
Second, since the photograph was made from a long distance away with a telephoto lens, there's some contrast loss and color shifting caused by scattering and haze in the air. If you've ever tried making photographs out an airplane window, you know what I'm talking about. The whites come out looking fine, but the scattering fills in the shadows, so that they're bluish and the scene is lower in contrast overall than you'd like. In the case of my photograph, the scattering is more greenish than blue, probably because of relatively low grazing light and all the foliage, but the overall effect is similar.
The third problem is that my telephoto lens had some uncorrected secondary lateral chromatic aberration. In other words, a bit of color fringing. I find this especially annoying in dye transfer printing, because it looks like I'm a sloppy printer and have misregistered the matrices, when it's the fault of the lens.
Solving the first problem takes a bit more cleverness than with conventional printing. Remember, this is a separation process: there are three separate exposures on three separate sheets of pan matrix film, one for each primary color. Manual dodging and burning in just won't cut it; there's no way I could do that precisely enough to avoid color fringing.
One of the smartest things I ever did, early in my dye transfer printing career, was to make up a bunch of dodging and burning masks out of sheets of 4x5-inch B&W film. I probably have 100 of these, in various densities, abruptness of gradients, and shapes of gradients (lines, arcs, and angles). The masks aren't sandwiched with the negative; they sit on top of the negative carrier, several millimeters away from the negative. That way, any dust or scratches or slight imperfections in the masks don't show up in the print.
When I need to do dodging and burning in of a dye transfer print I look through my assortment of masks and figure out which combination will do what I need. In this case I wanted a fairly sharp-edged burn of about a half stop at the bottom, and a much more diffuse burn of half a stop at the top. Figure 2 shows the two masks I used in combination with my negative for this photograph.
Reducing the aerial haze is pretty easy in dye transfer. I can mix up dye baths of slightly different contrasts. It's like making the curve steeper in Photoshop in one or more of the channels. In this case, I kicked up the contrast of the magenta dye bath by about half a grade, to neutralize the excessively greenish shadows.
Getting rid of the lateral chromatic aberration is a tricky thing, but it's doable (sometimes) with sufficient care. How did I do it? I changed the height of the enlarger head slightly between the exposure separations. That alters the relative magnifications for the different separations, and if I do it just right, I can undo chromatic aberration. For this photograph, a height adjustment of 1 mm was what I needed to eliminate the color fringing (figure 3).
Sometimes this trick doesn't work, and the separations fail to align properly. I suspect that's due to irregularities in the gearing of the enlarger head that causes it to slip a bit sideways if the gears are in just the wrong position. This time I was lucky. The trick worked perfectly and reliably for this photograph.
Just another ordinary day in the darkroom, when you're a dye transfer printer.
©2013 by Ctein, all rights reserved
Ctein's weekly column usually appears on Wednesdays, but this week we were busy with the sale on Wednesday. (May the admiring editor just add that this is the first time he has ever heard of adjusting enlarger height to correct LCA, and his mind is suitably boggled by the degree of precision in technique this requires.)
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