What to do about bad data appearing in scans of old photos?
December 17, 2007 4:21 PM   Subscribe

I'm scanning old family photos and the scanner appears to be adding colored pixels to black and white photos. What do I do now?

I'm trying to archive old photos dating back as far as 1912. Most of the ones I'm scanning are 30s and 40s right now. I'm trying for archival quality so that we can keep these photos at this quality level forever. After all, the photos aren't going to get any better with time, right?

I'm scanning at 600 dpi into uncompressed tiff files. Looking at these files closely I'm noticing that the somewhat older scanner I'm using is inserting colored pixels here and there, and sometimes in horizontal lines. I suspect the thing is just old and dying, but I was almost done when I discovered this and I dread going back and doing this all again.

I was also trying to scan the images without taking them out of their mounts - the less handling with old photos the better, right? I figure that there may have been some stray light getting into the sensors, but that wouldn't explain whole lines of color would it? I figure that this points towards the scanner head messing up.

I've put up an example on Flickr here. Take a look at the foliage to the left of the knee of the girl holding the dog.

Do I need to rescan all of these images? I figure that maybe some of them are ok - how can I pull up a color palette in Photoshop so that I can see what colors exist in a picture? I've got Photoshop CS3, not that I know how to use it very well. Any advice on how to proceed?

I realize that this is a lot of questions. I feel overwhealmed with the idea of re-doing all of this scanning, particularly now at Christmas. I was supposed to have all of this done for my Aunt by now, and I feel like I'm letting my family down.
posted by Jupiter Jones to Computers & Internet (16 answers total)
you are probably scanning them as color rather than black and white. if you have a program like photoshop, youcan convert them to black and white.
posted by violetk at 4:26 PM on December 17, 2007

You can quickly change these to grayscale in Photoshop. I have CS2, but I'm sure it's not that different in CS3. On the image menu, choose adjustments, mode and then grayscale. (I don't have PS on my work computer, so that may not be the exact path.)
posted by desjardins at 4:29 PM on December 17, 2007

By the way, you don't have to do this one at a time. You can record an "action" in photoshop (like a macro) and then do all the files at once. Again, I don't have CS3 (or anything right in front of me) but search for "recording photoshop action" and "automate batch" and you can figure out how to convert a whole folder of photos to grayscale at once. Don't stress - this will take about 5 minutes.
posted by desjardins at 4:32 PM on December 17, 2007

There is a difference between a "black and white photo saved as a color file" and a "black and white photo saved as a black and white file". You seem to be doing the former. This means the computer is actually storing a red, green and blue value for each pixel in the image, and in the case of a slightly poorly-calibrated scanner, these red, green, and blue values might not line up exactly, resulting in the sort of effects you are seeing.

The solution if you're continuing to scan photos, is to make sure the scanner software is set to scan in black and white mode rather than color (this is usually faster as well).

The solution for your existing photos is to simply convert them to black and white format in software. Photoshop will do this, yes, but so will pretty much any photo editing and managing software out there, including the excellent Picasa, free from Google.
posted by Jimbob at 4:33 PM on December 17, 2007

You mean that slightly blue and slightly red tint on the edges of the black and white borders? That'll be because of the alignment of the RGB lights in the scanner. I'd ignore it. Particularly since the images aren't greyscale (they have a slight tint, confirm it by changing the "mode" to greyscale and you'll see what real greyscale is). No scan can ever be a perfect copy and these look fine.
posted by krisjohn at 4:35 PM on December 17, 2007

Don't worry about it. Your aunt won't even notice, b/c I stared at that photo like it was a Where's Waldo and I couldn't see it.

That being said, I know that Jpeg artifacts often give you some strange prismatic colors but I've never heard of an uncompressed format doing it before... unless for some reason your scanner compresses and decompresses the image. That would just be weird. Anyway, you have to understand that black and white in "real world" colors do not fall strictly into the black/white continuum in computer colors, nor should they. If you took the image and desaturated it entirely in Photoshop, you might find that it loses some depth or vibrancy.

If you must look at a color table, though, you can go to Image --> Mode --> Indexed Color. Then, once you've, erm, indexed your colors, go back to Image --> Mode --> and click on color table.

If you see some neutral pinks, beiges, greens, do not worry.

If you see bright reds, aquas, magentas, or basically any color that can be expressed in a triplet of F's and 0's in hexadecimal, something's up with your scanner, and you still don't have to worry, because no one can see it. :)
posted by reebear at 4:36 PM on December 17, 2007

OK, I'm bored at work. Here are links to (really simple but) detailed instructions:
1. Converting from color to grayscale in CS3.
2. Creating an action.
3. Creating a droplet (that will let you automate the action across a folder).
posted by desjardins at 4:41 PM on December 17, 2007

Can I just say, that while you're probably right about trying to handle old photos as little as possible, scanning them within their mounts may result in slightly out of focus scanned images - scanners are calibrated to focus on the exact surface of the glass, and if something is only a few mm above the surface, it can start to get blurry. In the case of the image you've linked, it doesn't seem to have affected it that much, but for super-clear photos you might want to think about scanning the photos without the mounts.
posted by Jimbob at 4:46 PM on December 17, 2007

The solution if you're continuing to scan photos, is to make sure the scanner software is set to scan in black and white mode rather than color (this is usually faster as well).

Note that the mode you want may actually be called "grayscale." "Black and white" in many cases can mean "monochrome" which is probably not what you want (i.e. it's JUST black and white, no grays - ideal for scanning newspapers, say).
posted by wackybrit at 5:15 PM on December 17, 2007

your scanning software may have some sort of descreening or moire filter defaulted on to help with image quality when scanning from printed images. Such filtering wouldn't be calibrated for working with b&w photos and so could create artifacts like those you describe.

If you can eliminate the effect I think rescanning is a good option. Personally I like to scan b&w photos in full color mode because storage space is cheap and old photos usually have a bit of warmth to their greyscale that I like to preserve. If that isn't something you care about batching them all to greyscale files should make these random pixels disappear completely.
posted by subtle_squid at 5:24 PM on December 17, 2007

As someone else who is scanning gigs (and gigs and gigs) of old family pictures, let me recommend this - scan them in color. I've done a lot of post-processing work on my family's pictures, and there's a ton of them, especially the ones from the 20's and 30's, for which a light sepia cast really works well. Hard drive space is cheap (though scanning time is less so), and someday you may appreciate that color scan.

For the ones you really want to convert to black and white, my favorite method for it is well-documented at Slower.
posted by god hates math at 5:30 PM on December 17, 2007

While technically these are Black and White photos, the prints contain other colors and are slightly tinted from age. If you want to keep the scans looking exactly like the prints, you'll need to scan in color. As god hates math correctly states, you can always get B&W from color but not the other way around.
posted by doctor_negative at 6:05 PM on December 17, 2007

Response by poster: It's true that I do have to zoom far into the image to notice the colors. I only clued in to the color being there when a couple of the images had really bad lines in them, and those only had streaks of color. I tested, and you can still see the colors if you zoom right into the jpg I posted on Flickr.

I am definately scanning in color. The black and white option I'm given with this scanner software is just black and white, not grayscale. I don't have it attached to the computer at the moment, so I can't double check, but I didn't notice a grayscale option, which is what black and white photos actually are.

That said, the colors that appear are definately not from aging or any natural process. I'm talking about colors like cyan and red appearing in noticable streaks.

I'll give a couple of those photoshop tips a shot and see what happens.
posted by Jupiter Jones at 7:19 AM on December 18, 2007

IMHO, it is a travesty to scan age-toned images as b&w. Try making them duo-toned at least to maintain some of the old-fashioned qualities. I also have to question your basic premise;

I'm trying for archival quality so that we can keep these photos at this quality level forever. After all, the photos aren't going to get any better with time, right?

Properly stored, these original prints will outlast both the TIFF image format and the cds you burn them on. By all means scan them to share and make good quality prints from the scans to display. The originals should be stored archivally away from light, heat, and humidity. If an image has survived without noticeable aging from the 1930s or 1940s, it will continue to last if taken care of.
posted by JJ86 at 7:24 AM on December 18, 2007

Response by poster: I indexed the color and got the colors - what do you guys think?

I also zoomed in on the problem for those who can't see it. I'm freaking out a little less this morning and wondering if you guys think this would really be a problem in blowing these pictures up and printing them.
posted by Jupiter Jones at 7:41 AM on December 18, 2007

I'm pretty sure this isn't going to be a problem with printing - think about the numbers.

You're scanning at 600dpi. You'll probably be printing at 300dpi, or slightly greater. You're talking about a very small number of pixels, which translates to hundredths of an inch. I didn't see what you were talking about until you posted the zoomed-in shot, and I seriously doubt that anyone will notice the color in a print unless it's of a significant size - probably bigger than the original photo was.

I'd do one of two things -

1. Just get a print made (use ezprints, or one of the other web services that makes archival-quality prints), and see how it turns out.

2. Copy the background layer. Desaturate it. (cmd+d) Mask out the whole layer, and then, using a brush with really soft edges, paint in the desaturated layer over the background layer. Considering how few pixels it is, it'll be even harder to notice than the color pixels. I think that'll work pretty well, and isn't that time-consuming an issue.
posted by god hates math at 10:12 AM on December 18, 2007

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