Scanning photo slides is similar to scanning film negatives. There are a host of specialized scanners, adaptors, and software packages designed for optimal results. But if all you have is a flatbed scanner, there are some simple DIY tweaks that can produce decent results.
Step By Step
1. Clean Up
Clean your scanner bed and film slides thoroughly with a dry, lint-free cloth. This will make a difference during the photo touch-up process.
2. Get Backlighting
Slides, like negatives, require backlighting. They're made to show their image when light is passed through them. You can use a bright white glossy piece of paper, such as film paper, to act as a reflector or you can try to build your own backlighter.
2a. Build a Backlighter
Basically, you need to fold a piece of glossy white paper in a triangular fashion. This is a convenient template, provided by Dan Maxwell, who pioneered the technique. Once you've folded the triangular box, tape it together.
3. Up the Resolution
Place your clean slide on the flatbed scan and put your backlighter box over it. Set your scanner and scanning software to the highest resolution possible. You want the most information possible as the slides are very small and will need to be blown up to make full-scale photos. Set your DPI as high as you can, and increase the brightness, if possible.
4. Photo Edit
Your scanned image will likely be darker than you'd like. In a photo editing tool, such as Photoshop, you can adjust Brightness and Contrast to lighten the image. You'll also want to cut the image from the white slide borders in a photo editing program and increase the image size to best suit your purpose.