The Long Now Photography Project Phase 1

From crispyneurons

the visual archeology of kin

Introduction | Phase 1: Scanning | Phase 2: Post-processing

[edit] Scanning

The first step in the process is to scan one or more photographs. There is a bit of preparation to be done beforehand. The scanning software needs to know what kind of scanning you plan to do. In this case, I will be scanning both color and black-and-white photographs. Since scanning can occur at all kinds of resolution, I had to establish a resolution quality benchmark that I could live with. There is a tradeoff to consider: while ideally you want the pictures to be at the highest possible resolution, in reality limitations of things like disk storage and network bandwidth become very real constraints. Sometimes the quality of the source prints, or even the scanner itself, can be a constraint.

Originally, my quality benchmark was to make them come out with the same resolution and quality as the pictures my digital camera produces. My camera is capable of producing a 3.3 megapixel image. At its finest quality, it saves a color photograph at 2048 pixels wide x 1536 pixels high. This results in a JPEG image file that is about 1.3MB. For several years I have used this, and it's been fine.

But when my camera came out, 3.3 megapixel was the very top end of image resolution for the prosumer digital camera world. These days, it's more like 8-10 megapixel! I ran the numbers on 8 megapixel images, and I decided my computers are inadequate for dealing with thousands of images of that size. So I have selected 5 megapixel as a compromise. 5 megapixel implies an image that is 2592 x 1944, resulting in a 1.5MB JPEG file. That's not bad. I want my scanner to produce images as close to this as possible.

Trial and error has taught me that in order to reach that final resolution, a typical 4" x 6" 35mm print should be scanned at 700 DPI (dots per inch) or higher. Adjust this number higher for small pictures (like a wallet print) or lower for large pictures (like an 8" x 10"). You can scan a much higher resolutions, if you want, and if you have lots of disk space and memory. Lastly, the descreening option should be set for 'photo' or 'magazine.'

(Yes, I recognize that this is much lower resolution than 35mm is capable of handling. So why am I willing to compromise? Because it's pragmatic to do so. Most of these pictures are family-related, and so the resolution isn't as important as it would be for purely artistic photography. Also, many of the photos aren't even 35mm, or even color for that matter. Better to accept the limits of the technology now than it is to wait the years it would take for the terabyte disk drives, next generation DVD discs, gigabit wireless Ethernet, and 24" 300 dpi monitors to reach non-insane price points.)

When using a flatbed scanner, which is the only practical choice in this setting, the scanning process is very cumbersome. It goes like this:

• First, place the photo on the glass window of the scanner.
• Next, do a preview scan. This is a lot quicker than a full scan, and helps you be sure that the pictures aren't crooked.
• Then you select the region of the preview that you really do want to scan, since you only want it to scan precisely where you put the picture, not the entire scanner bed.
• Finally, scans the photo. The scanning software saves the resulting image to a file on your hard drive.

As a practice I try to scan multiple pictures into a single file. Naturally, if you can scan three pictures in one pass, you've tripled your productivity here. But this is practical only if the pictures are part of the same group, like an event, because the filename of the scanned image can only convey so much information. (I'll get into this more in the post-processing phase.) VistaScan saves the scanned images as uncompressed TIFF files with names like 'VSImage_1', 'VSImage_2', etc.

So you've scanned the photos, and you're all done, right? Wrong. You still have to deal with these problems:

• File size. These raw TIFF images may range from 20-80MB each. The target file size is in the neighborhood of 1.5MB per image.
• Resolution. The raw images may be several times the target resolution of 2592 x 1944.
• The image may need to be rotated 1-2 degrees to compensate for how the photo was placed in the scanner.
• Scanner cruft (unwanted portions of the scanned image) will need to be cropped off the edges.
• The contrast may be sub-optimal, resulting in a dim image.
• The color saturation may be too low, resulting in muddy colors.
• The white balance of the image may be off, due to problems in the original print.
• The images may contain problems such as windshield glare, red eye, or scratches that are all fixable via Photoshop.
• The raw scanned image may actually be comprised of several separate photographs, whereas each image should comprise one (and only one) photo.
• The filenames of the raw images are completely meaningless, and don't describe the picture.

Which brings us to the next phase: post-processing, where all of these problems are solved.