Everyone has a photo scanner these days. Most of us will slap an old photo or document on the glass from time to time - and then kind of just hope for the best. Finally, here are the settings - simply explained - for getting what you need from your scanner.
So, you've fired up the machine, you have laid down your image on the scanner glass - what now?
Umm, can you back up just a sec? The glass. I don't know about you, but the glass on my scanner gets all kinds of dust and smears on it. So best to give it a bit of a wipe with a cloth and maybe Windex. If you have a can of air - blow the dust off the glass too. Check the photo for dust too while you are at it (but don't spray it with anything whatever you do!)
OK. The photo is back on the glass and you're thinking that this is a bigger job than you imagined. Calm down - it will all be over in a jiffy. Because, there is really only one setting that you need to worry about and that's resolution - or dots per inch (or "dpi"). This is important because dpi (or ppi - "pixels per inch") sets both the quality and size of your image (I am going to use "dpi, but read "dpi or ppi").
Scanner resolution: 96 dpi or 300 dpi
Your scanner should have a setting for "resolution" and it should give you some choices either in dpi ("dots per inch") or ppi ("pixels per inch') - for all practical purposes they are the same thing. Your choice - depending on your scanner - will be something between 50 and 10,000 dpi. That narrows it down eh?
The choice you make will depend on whether you intend to use your pictures on computer screens and monitors; or if you will want to print them. Your average PC has a default resolution of 96 dpi, and print requires 300 dpi. So use these settings for those uses. If you are going to email or post the images, scan at 96 dpi. If you will want to print, scan at 300 dpi.
(Why 96 dpi for screens but 300 dpi for print? Because of the way computer screens are back-lit and normal viewing distances for computer work, you can get away with less dots. In short, the greater the viewing distance, the less dots you need. Normal viewing distance for reading is pretty close and there is no back light; so you need 300 dpi for print.)
Picture size: moving off 96 and 300
Scanning at 96 or 300 works great for most situations. But not all.
For example, what if your picture is really small? Let's say you have an old passport photo - sized 1" x 1.5". And let's say you want to email it to a cousin, but you may want to print it later. You scan at 300 just like the article said. You will have plenty of resolution to print it. But will be the same size as the original - really small.
If you want to boost the size of your image, increase the dpi setting on your scanner. Just do some simple math to work out what the setting should be. If you would like that old passport photo to be 4" x 6" when printed, then scan at 1200 dpi.
(Get it? Multiply every inch of your original photo by the scanner resolution to get the final size.)
Scanning images for video
A lot of TV and video media use 72 dpi. But I would ignore that fact when scanning photos for a video project. If you are editing photos into a video editing timeline (as I often do in my life story videos) then the program will take care of any necessary resolution adjustments. Just make sure that you keep in mind that the standard definition video picture frame is 720 pixels wide, and that HD video is 1920 pixels wide. Any image you use for standard definition video or HD should at least be as wide as the picture frame - and wider if you plan to zoom in.
Resolution for scanning negatives
Calculate your scanner resolution settings in the same way you would a photograph. If it is a 35mm negative (around 1" x 1.5") then you will want to scan at a minimum 1200 (makes a print 4" x 6") - and 2400 is better (and 4000 is even better - but your file size is getting pretty big at this point). The larger the negative, the lower you can go - just ask yourself will it be used on the computer or printed - then do the math.
All those other settings
Your scanner will probably have all kinds of other widgets and what-nots. If you have an editing program, then you are probably better off leaving them all unchecked and doing your fixing in your editing program.
If you are not going to edit in a photo program, then there is little harm in checking the "unsharp" box (it actually makes the photo sharper - go figure).
A word about old photos
Most old photos have a lot more information than you can see. In a lot of cases, the old photo was printed in a sandwich with the original negative. There is often a ton of information in them and they will repay a scan at a high resolution.
If you involved in a genealogy or a family history project then you will be handling a lot of old photos. And you will probably notice that many of the older images - those that were taken and processed before the color revolution - are really pretty good. I do a lot of photo restoration associated with family history and life story video projects and am constantly surprised by how early - and how well - the black and white photo technology was perfected. And I am often shocked - when the image is carefully scanned and restored - how much fresh detail is revealed. Sometimes you discover new people in the shot! So really crank up the resolution on those old images and see who you can discover in the detail.
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