Preserving 35mm photos on a computer is a great way to keep them safe, and chances are that either you or someone you know has an old box of irreplaceable memories waiting to be scanned. The problem is that an ordinary scanner doesn’t really scan slides or negatives properly. The reason is that slides should be illuminated from behind, while conventional scanners are designed to capture reflected light from a document.

You could go out and buy a dedicated film scanner, but there is a much cheaper alternative if you already have a flatbed scanner or scanner/copier attached to your computer. A simple cardboard adapter can be used to capture the light from the scanner and reflect it behind the slide. Once the adapter is in place, you can scan the slide as though it were an ordinary document.

Project Steps

Take a piece of silver card stock, and download and print out the paper template on the plain (non-silver) side.

Cut around this shape with the scissors and fold the triangular wings upright so that the shiny sides of the card stock face each other.

Now fold the longest part of the rectangle in to touch the edges of the triangles, so that the whole thing resembles an open-bottomed triangular wedge with the shiny side of the card stock to the inside.

Tape the corners of the adapter together, and it’s ready to use!

To use the adapter, place a slide or negative onto the scanner, and then place the adapter over the top. For the best results, line up up one side of the slide with the center of the adapter. Leave the lid of the scanner open. If your scans have an uneven brightness, try adding a thin piece of tissue paper between the slide and the adapter. The tissue will diffuse the light, and stop the scanner from seeing the space behind the slide.

Take a preview scan with your favorite image editor and crop the scan to the area of the slide. The higher the resolution you scan at, the more detail you will get. I recommend setting the scanner to at least 1200 DPI.

If you are scanning negatives, you need to perform a little bit of additional computer jiggery-pokery to reverse the color of the negatives. Most image-processing programs, including Microsoft Paint, will have an “invert” function that will reverse the colors for you. You might also want to adjust the brightness and contrast of the images to make them look better on the screen.

You will probably notice that there are a few specks of dust on your slides when you scan them in. This is usually unavoidable, but a soft lens-brush or a clean makeup-brush can help minimize the problem. To remove any persistent specks or scratches, you can use a photo editor with a “heal” tool. If you don’t have a program that can do this, you can download GIMP or for free.

This image shows the raw scan on the left, the inverted scan in the middle, and the final image with the scratches and dust removed on the right. The entire process took less than 10 minutes to complete.