COLOR3LAB
a digital and traditional commercial lab
SUBJECT: Enlarger Alignment - a "tall" tale about how we use zig-align's ZTV!
Imagine that you wish to align a single enlarger to make some 11x14s using 35mm negatives for exhibition purposes. Perhaps you know that the highest quality prints come from a well-aligned system. And you may have heard that a zig-align LED module system with "naked eye" viewing of the alignment pattern will provide a simple and accurate method to achieve this.
A typical setup usually involves a 50mm lens which, when set to 1100% magnification, yields a working distance from negative to paper of approximately two feet. This is a convenient distance for viewing the alignment pattern as well as for adjusting the enlarger.
Now imagine a similar situation scaled up for a commercial lab. The object is to produce a 6x9-foot print from an 8x10-inch negative. And the print must be exhibition quality, just like above. To get good corner-to-corner light coverage, a 360mm lens is needed. The working distance from negative to paper then jumps to around 15 feet to achieve the same 1100% enlargement.
(Producing unspliced prints like this in widths over 50 inches is more and more the only kind of task left to traditional commercial photographic enterprises. It is one of the things we do at Color3Lab.)
At these distances, the task of adjusting the enlarger while viewing the alignment pattern created by the zig-align LED module becomes nearly impossible. You must view the pattern when the module is up 15 feet, lower the enlarger to make an adjustment, raise it to view the pattern again at 15 feet, lower it to make another adjustment, etc. Or have an assistant, who does the viewing of the pattern, yell out instructions to the person making the adjustments. Both methods are unsatisfactory, leading to acceptance of compromised alignments, either out of frustration or sheer exhaustion.
The solution to viewing the pattern when the enlarger is out-of-reach is zig-align's ZTV. Now you do not need scaffolding or a ladder just to view the pattern because one person can view and adjust simultaneously. The product works by employing a tiny chip camera and a video monitor, making it easy to see the pattern while making adjustments even if the module is in a remote place. And the pattern is MAGNIFIED, a huge advantage when the working distance is large.
Now the monstrous task of making a 1 foot square negative stage parallel to a 50+ sq. ft. paper plane 15 feet away becomes as manageable as the analogous task on the smaller enlarger at 2 feet.
But the benefits of the ZTV don't stop with that. There is still the often-overlooked lens alignment of the enlarging system. The lens must have its focal plane precisely parallel to the negative just behind it, as well as to the paper farther in front of it. The act of focus must superimpose the focal plane on the paper precisely. Without at least the same alignment accuracy at the lens as between negative and paper, optimum corner sharpness will not be achieved except at very small apertures. And true rectilinearity on the paper will not be achieved regardless of aperture.
So additional adjustments at nearly the same 15-foot distance are necessary. Without ZTV, you might be tempted to skip them because of the distances involved and the difficulty in somehow gauging the lens' true alignment.
With the simple-to-use tools of an LED module equipped with ZTV, one person can align a commercial mural enlarger in an hour or less and always get four-corner sharpness at a wide-open aperture (assuming a top quality lens). This is accompanied by errors in rectilinearity of the image (assuming an accurate negative) less than the thickness of the tick marks on a standard tape measure. There is no other system on the market today that allows you to reach this level of optical precision from ordinary enlarging equipment.
Alignment with zig-align can allow over-sized, traditionally produced prints to compete favorably with completely digitally produced prints. And if you use good light sources and modern lenses (modest apertures optimize illumination evenness; zig-align optimizes uniformity of sharpness), the level of visual quality can be phenomenal even with older equipment long out of factory tolerances.
This being said, a strange thing happens. When you have ZTV equipped with zig-align's LED module, it quickly becomes the tool of choice for that small enlarger setup, too, because of the benefits of continuous viewing and the greatly magnified alignment pattern. It encourages precise alignments performed "regularly and often." Now the former burden has become a mini-task that is delightful and fast rather than dreaded and onerous.
Richard
Politowski
Printing Dept. Manager
Color3Lab, Inc.
San Francisco, CA
Color3Lab produces
multiple copies of large prints, digital or traditional, for the commercial
trade.