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Sunday, April 15, 2007

Notes on Scanning

I wanted to make a few notes about scanning transparencies and prints.

Epson makes a scanner called the V750. It's pretty cool. It has a built-in light box for transparencies in the lid.


In addition to the usual faire, you can scan transparent positives and negatives up to 8" x 10" at resolutions up to 6400 dpi.

At 6400 dpi, each square inch of the image is 41 Megabytes.

For a 4" x 5" Hasselblad positive or negative transparency this works out to about 819 Megabytes per image. Just remember "4x5 is a gigabyte".

If you have many film products to scan you may want to purchase an additional external hard drive that you can throw in the car and drive to your print fulfillment vendor. A 400 Gig USB 2.0 drive is $139 at this writing, but you might want to go bigger. Uploading gigabyte images is tedious at best.


Preparing Your Machine and Workspace

You will want to max out your machine with RAM. RAM is cheap compared to your time.

You will want to make sure that your machine supports USB 2.0. Dedicate a table to the scanner so that your workflow is convenient, especially if you are working in a team environment. People need room to move and think. You might also want to have a light box and a film loupe so you can review your materials prior to scanning.


A can of compressed air is useful for blowing the dust and lint off of film materials. I highly recommend running a dust remover like the Oreck or Multi-Tech in the room where you are handling film. Also wear inexpensive cotton gloves. Fingerprints contain acids that will deteriorate your materials long-term.


Connecting the Scanner

The vendor provides disks with various drivers and utility software. Plug the scanner into a UPS power strip to protect its delicate circuitry and connect the USB to the back of your machine where it will be out of the way.

Running the Scanner

After the scanner is connected and configured correctly, run some scans at LOW resolution. There is usually a preview mode but keeping the "dpi" low will let you get your feet wet without using large amounts of scanning time or disk space. After you get your workflow down, you can crank up the resolution. I suggest 400 dpi just to see how things are looking. You can also rehearse the corrections you want to make in brightness, contrast, etc without running into space or time problems.

After you are happy with your process, double the dpi to 800 and make sure everything is ok. You can continue doubling until you reach the peak resolution of the scanner. 6400 dpi is four doublings. Plan on the fourth doubling to take sixteen times as much time and disk space as your early fast runs, which should be less than a minute.