I digitised some 30-year-old Kodachrome slides this week. I’ve gone through this process three or four times before, but this time was more successful. The following notes are for my own benefit, to refer to the next time. I’m publishing them here in case they’re of use to anyone else.
- put slides on a light-box;
- photograph them using a digital SLR and macro lens, with the camera on a tripod;
- post-process in Adobe Lightroom.
Photographing the slides
[These notes refer to slides, but they should work equally well for negatives, although you will obviously need to convert your copies to positive images during the post-processing stage.]
- dust the slides thoroughly with an air-puffer beforehand. (Despite this, there was still quite a lot of dust on my slides, so I would use an air-puffer with a soft brush next time. Any remaining dust marks can be removed in Lightroom, see below.);
- your camera will be pointing downwards, so make sure the light-box is situated low down, possibly on the floor, to ensure that you can see through the camera eyepiece. The best arrangement depends on the focal distance of your lens;
- to avoid image distortion, it’s important to position the macro lens directly above the centre of the slide, at right angles to it (although minor adjustments can also be made in the post-processing stage);
- if your camera allows a live-preview on the screen on the back, use it to make sure you’ve lined up everything as best you can. (My camera’s preview allows you to overlay a rectangular grid pattern, which was extremely useful in this instance.)
- to keep it simple, turn any portrait-orientation photos through 90 degrees and shoot them sideways, so you don’t have to realign the camera;
- I thought I would be able to get away with using a wide aperture (i.e. a shallow depth-of-field), thereby allowing a faster shutter speed, as I would be photographing something flat, but, in practice, this made focusing difficult. I didn’t experiment much, but an aperture of f/14 worked well for me.
- I set the camera’s ISO at 200, which seemed to work OK. In my case, this gave shutter speeds of around ¼ second;
- I found I obtained better results under-exposing by one stop;
- you need to re-focus the lens with each new slide;
- I engaged the mirror-lock facility and 2-second self-timer (controlled by infra-red remote control) to minimise camera-shake.
Post-processing in Lightroom
The images look pretty crap, don’t they? Don’t despair, you can fix a lot with Lightroom:
- Crop and realign the photos as appropriate. If you failed to position the lens exactly perpendicular to the surface of the slide, resulting in a distorted image, you can adjust this using Lightroom’s Lens Correction settings (see the Manual tab), but it would be better to get it right in the first place;
- remove any remaining dust spots, hairs, etc., using the Spot Removal Tool;
- I found most of the unprocessed photos were somewhat flat, but the details was there, once I adjusted exposure, contrast, blacks, whites, etc. using Lightroom’s Basic adjustment settings (I won’t go into details: if you own Lightroom, you should already know how to use these);
- this one was the real revelation: once you’ve got the images looking as good as you can using the basic settings, adjust the Sharpening settings. For me, this vastly improved the resultant images. The combination that worked best for me was:
- Sharpening: around 60–70;
- Radius: around 1.3–1.6;
- Detail: around 25 (it was adjusting the detail that made the biggest improvement).
- on some slides, you might need to remove some Luminance noise using the Noise Reduction facility.
...You’re never going to obtain perfect digital copies of your old slides this way, but it works well enough for my purposes.
The slides I describe scanning above were for use in an article about my 1985 trip to Shetland, entitled 136 snail shells & a pint of shorts.