Scanning Old Prints
By Mike Pasini, EditorImaging Resource Newsletter
It fell to us recently to restore some very old prints, the earliest of which
were made in the late 1800s.
While it's as feasible to copy prints with a digicam as it is with 35mm film, assuming the proper setup (illumination angled at 45 degrees on either side and the camera squarely mounted), we preferred to scan these.
Scanning has several advantages:
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• Even illumination. No worries about setting the lamps or flash at 45
degrees and checking for even coverage.
• Flat subject. No worries about paper curl. If you shoot with the camera through glass, you're liable to get nice sharp photos of dust on the glass.
• No lens distortion to worry about.
• Custom (and precise) cropping.
• Variable resolution. A number of these prints were quite small. Our target size was 8 x 10-inch prints, so we wanted to be able to scan the originals at a high enough resolution to get a printing resolution of roughly 150 dpi.
But you can do quite well in a pinch, as we've said before, copying photos with a digicam that has an image size that can accommodate your print size. Once you've got a reliable setup, it's faster and it can accommodate even awkward originals. Like those framed heirlooms.
In addition to setting our sampling size (or resolution) to somewhere between 300 and 600 dpi, we set our capture mode to grayscale. These antiques were, of course, made well before color photography was common. A few were sepia toned, but we decided to standardize them all as grayscale images.
That was an artistic decision. We simply wanted them all to match. If we later decided to print them in sepia, we could run a Photoshop action to convert them to sepia prints with consistent tone.
Our Obsolete Scanner has a very functional Photoshop plug-in that lets us do all sorts of things which we usually prefer to do post-scan (where we can undo or fade the effect). It's very good at picking the highlight and shadow, though, so we let it do that when we can make an intelligent selection. And it shows us what it's done in the preview, so if there's any confusion, we can set the highlight and shadow points manually before the Obsolete grinds away.
But no matter what we did on a couple of the images, our black was just a horrible, gray shadow. No black at all. Turns out these images (which were not the oldest) were printed on a textured paper. A sort of linen-embossed texture. Excellent for napkins. Lousy for Obsolete Scanners.
All, fortunately, was not lost. By scanning in RGB mode, the scanner's native mode in fact, we were able to pick up a black in these prints on difficult papers. A conversion to grayscale in Photoshop then let us continue on our merry way.
Moral: To get the maximum density range from a difficult black-and-white print, try scanning in RGB mode.
