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High Ends Scans of Antique Photos for Digital Restoration


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I own CS3 & CS6 and have completed some basic restoration work, but I have two 1870s Carte de Viste images that will require 3rd party restoration and colorization.

As each is small, both being around 2.25" x 4", I am interested in scanning them at a very high optical dpi so as to enlarge them as much as possible. This allows them to be printed at a larger size later on and gives the digital artist more to work with.

I have a Epson V600 which the manufacturer states has a 6,400 DPI optical resolution; however, 3rd party testing shows no additional detail is gained above 1,500 so its a typical manufacturer half-truth.

I am looking for a high quality scan that actually offers a optical scan of 6,400 DPI or higher. Such scans require a high end scanner such as a Heidelberg Topaz which do not appear to be available in my state at all as most print firms can't afford $35,000+ scanners.

For testing purposes I've completed a couple scans with the V600 at 6,400 DPI which produce files just over 2GB, which is not a problem as a I use a Mac with 48GB of RAM installed.

At 20% one begins to see microscopic cracking in the photographic paper that is not visible my the naked eye (which can be cleaned up using various techniques); however, this brings of the question how much a actual high quality scan would be beneficial. I am very hesitate at sending these images out of state by U.S. Mail or UPS as they are not replaceable and are valuable.

I've only been able to find a couple services with such scanners and they are on the East coast; however, I don't really like their restoration work examples.

Any suggestions as so what type of service I should be looking for.
 

Tom Mann

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As I am sure you must know, the usual advice for scanning prints is that 300 ppi is all one needs for ordinary print duplication and restoration tasks. I'm not sure I quite believe that, so I usually go with 600 ppi.

However, in my experience, (I have owned a v700M-pro with wet mount adapter for several years), anything above 1200 ppi for prints is overkill. As you probably also know, unlike the single lens optical system of the v600, the v700 switches to a higher magnification lens when set to high resolution, so, I certainly believe my results when I call for resolution increases from 1200 to 2400, let alone all the way up to its 6400 ppi maximum.

What I see when I go above 600 ppi is microscopic structure in the paper, much like you would see when viewing through a microscope, but no more detail whatsoever in the image. This sounds similar to what you have described.

If the purpose of the scan is to produce archival, museum-quality *EXACT* reproductions where even every detail and imperfection in the paper must be preserved for future generations, then, of course, go for all of the resolution you can.

However, if the purpose of the scan is to produce a large print that looks good to the eye, my suggestion would be to have your pieces scanned at 1200 or 2400, then, in postproduction, use the frequency separation technique to replace the ultrafine, aged texture from the scan of the aged art with an ultrafine scan of a similar piece of photo paper which is in better shape. This is exactly analogous to using the frequency separation technique for retouching of the skin on portraits.

Some of the benefits of this method include being able to have the scans done at lower cost, locally, and without using a potentially damaging wet mount.

That being said, I must confess that I have never actually replaced paper texture for very high end print reproduction work. I have read about it, and it sounds very reasonable, but I have no 1st hand experience with this technique. I just tried to do a search for the article I read, but couldn't find it. I will keep looking. In addition, a friend has been on staff at the National Gallery of Art in Washington, DC for decades and is involved in much of the highly technical restoration work they do (eg, laser and x-ray scans, layer tomography, spectroscopic determination of pigments, etc.), so if anyone knows about this, it would likely be him. However, given their budget, access to the very best facilities, and the fact that they are dealing with world class art, they probably have no need to "cut corners" like this.

I'll let you know if I find out anything.

Tom M
 

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