After our last article on scanning slides and negatives, some readers had questions. It's a fascinating topic, and of great potential value to the genealogist, so let's look at some of those questions and try to answer them.

Glass Covered Slides
Question:
I have several family photo color slides that were taken in the early 1950s. Each slide is covered with a piece of glass on both sides. The slide is sandwiched between the pieces of glass, and the glass is encased in a holder made of a dull finished metal. I use a good quality flatbed scanner and an attachment for scanning slides. However, the glass prevents the image from scanning on these slides. I was able to scan one slide by placing the metal-encased slide in a towel and tapping the glass with a hammer. The glass split into tiny fragments; I removed the slivers from the slide and pulled the slide through the metal frame. The slide scanned well, showing only a tiny scratch from the glass. I used Photoshop to remove the scratch. There must be a better way! Any advice? Thanks

Answer:
It sounds to me like you have a glass slide, sandwiched with another piece of glass in a metal case. I would be surprised if the metal case couldn't be disassembled, and the glass carefully separated. The slide will have two sides-–a glass side and an “emulsion” side. Then you could scan the slides using your attachment for scanning slides. Scan them with the emulsion side down, so the glass won't reflect the light. Please don't break any more glass!

Glass Negatives
Question:
I have over fifty glass negatives, sized 5x7 to 8x10, from circa 1850-1900. I would like to successfully scan them on my HP psc750 (printer-scanner-copier). Is this possible?

Answer:
I would be surprised if you can scan a negative that big with a multifunction printer/scanner. For one thing, you will want to have a film-scanning adapter so that you can shine light through the work, instead of reflecting it. For another, most film scanners top out at 4x5 inches. There is hope. Look for a scanner that comes with an optional “transparency adapter.” This gizmo has a light and magnets in it and will slide above the negative so that the light shines into the moving scanner.

Oversized Negatives
Question:
I have a whole box of large negatives that I would like to scan. Any recommendations on a scanner I can purchase to do this? I have not been able to find a lot of information on scanners that can do this. It would make a good article. (Hint, hint.)

Answer:
I'm still really impressed with the Microtek I300, recommended by a reader. It's capable of handling negatives up to 4x5 inches, has Digital ICE, and can be found on Amazon.com for about $150 plus shipping. It also comes with an optional transparency adapter for another $75, but that's harder to find.

Enlarging Negatives
Question:
Could you possibly advise as to how you can enlarge negatives that you have scanned to your computer, as the scanned image is the same size as the actual negative—very small. Your article of today was great and most helpful to those of us on a small budget, so your reply to my query would be most welcome.

Answer:
I scan them at high resolution. This is purely a numbers game. My scanner, an Epson 1660, can scan an image at up to 1600 pixels per inch. First I scan a slide or negative at 300 pixels per inch. Then I scan it at 1600 pixels per inch. When I compare the two images, one is 5 times as big as the other. I put some examples on the RootsWorks site to show how much larger the image can be, and how sharp the pictures are even at that size.

DPI for Grandfathers
Question:
Thanks for your articles on the subject. The information is not so intense as to discourage grandfathers who are compiling their family histories, nor are they millions of pages long. Just enough to digest, get back to doing a family history and trying your hints as we go along. However, I do have a question concerning dpi, pixels, and something that turns out like a monster picture.

Is there a simple, graphic-like example that can be shown—described to a grandfather so he can use it as a guide when selecting the correct pixel setting in his scanner's software? I send this question as a person who continues to grapple with the "bigger is better" rules that have been driven home throughout his life.

I love using those high numbers and being able to really climb into the photos, but my server times out trying to send the "monsters." Is there a guide for perhaps the size print or negative that one starts with, and the size that we'd like to print and display?

Answer:
Well, let's think about this. The general formula is to take [the printed size] times [the printed resolution], and divide that by [the original object's size]. Keep everything in inches.

Let's assume that you are going to print the pictures at 300 dots per inch. That means that if you want to print something the size of a 4x6 photo, you would need to have 4 * 300, or 1200 dots high and 6 * 300, or 1800 dots wide.

If you're scanning a slide that is 0.9 x 1.3 inches to start with, your pixel setting would have to be 1200/0.8 or 1333 pixels per inch. Since most scanners don't have that exact pixel setting, you would probably have to go to 1600.

More Information
For links and more information about scanning, please see www.rootsworks.com/scanning. If you want to discuss your scanning challenges, please drop by www.rootsworks.com/forums. Registration is free, and I'd be interested to know what kinds of issues you are facing.

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