Slide Scanning – A Step By Step Tutorial

If you have been photographing for a while then you probably started with film, maybe in the 70s, 80s or 90s. If you were a photo geek then you’d migrate to slide film at some point. You got a higher resolution, and accurate colors. Slides were slides, and in theory the lab couldn’t get it wrong.

In came digital technology, and today you have a stack of slides (with probably some awesome shots) somewhere in the basement. Rarely you do the full bonanza of setting up the slide projector and do an old-fashioned slide show for your family and friends. Everyone wants it digital today, on a PC or Mac, on a CD or DVD.

So, you start to wonder – “How do I get brilliant scans from my brilliant slides?”

Now, I am currently scanning my complete archive in order to preserve it for the future (a rather boring task by the way), and so I thought, heck, why not write an easy-to-understand step by step tutorial on slide scanning? Well, here we go…

The Setup

I use a Minolta Dimage Scan Elite II for all slide scans. There is no point in using flatbed scanners. You need a dedicated film scanner if you want to get great scans from your slides.

The scanner is setup to scan at the highest possible resolution, 2688 x 4032 pixels, from a 35 mm framed slide. I use double-scan (2x) to eliminate noise from the scanner sensor, automatic brightness and autofocus to get a good basic scan, AdobeRGB as color space, and 16 bit as color depth to get the biggest possible image data for post-processing. And I still use Photoshop 7 for this. Other software capable of handling AdobeRGB and 16 bit works as well.

Here is the original slide (Tenaya Lake, Yosemite National Park, U.S.A.). The scanner generated a whopping 62 MB file, so you’ll need a fast computer and plenty of memory to fluently process the scan.

Tenaya Lake
Mark Zanzig/zettpress

One important reminder: Before you actually start post-processing, please make sure that you open the scan as “AdobeRGB” in Photoshop. Otherwise the colors will be way off.

Step 1: Tilt

I do most of my shots without tripod, so they are rarely perfect in terms of tilting. No problem. Before I start anything to do with Photoshop, I tilt the photo. Here, it’s 1.3 degrees clockwise.

Tenaya Lake

Step 2: Crop

Now let’s get rid of this ugly frame, and the white borders that appeared as result from the tilting. Away with it! Crop it!

Tenaya Lake Yosemite National Park

Step 3: Set the Gray Balance

The scan seems to have a slight color stain, with a tendency towards magenta. By adjusting the gray balance you get rid of this. I use the “gradation curves” tool in Photoshop (Ctrl-M). Pick the middle color picker, and click on a neutral point in the picture. You’ll find this neutral spot usually in a gray area, e.g. on a car tyre, a gray piece of clothing, a gray rock, or a white wall in the shadow. This steps needs some trial and error, but you’ll get better over time as experience sets in.

Tenaya Lake Yosemite

Step 4: Adjust brightness and contrast

Now, the scan appears a bit too bright. Let’s adjust the darkest point (here: to 16), and put in a bend into the brightness (here: 1.2) to improve contrast without creating too many dark areas. Then restrict the whole spectrum to 3 (the darkest pixel) to 252 (the brightest pixel). The idea is to get a nice brightness distribution across the whole image (i.e. not too dark, not too bright) without reaching the color values of 0 or 255. Again, you need some practice with that, but after a few dozen slides you will have a pretty good understanding what to do. I use the Ctrl-L tool for that (don’t know the English name for it). :-)

Brightness Adjustment in Photoshop 7

Tenaya Lake California

Step 5: Adjust the Color Saturation

We are almost done. Just the brilliance of the photo remains to be improved. I do this by carefully increasing the color saturation. Actually I am not a fan of those highly saturated photos – I rather prefer a naturally looking scan that comes very close to the mood of the original without looking too artificial. Usually I use the saturation tool (Ctrl-U) to add +5 to +17 in saturation. If you are absolutely unsure how to approach that one, I suggest to start with a high value, like +30, and if it looks way too colorful (artificial) then use half of that value. Repeat until you have a decent looking photo.

Tenaya Lake

Step 6: Adjust the Sharpness

Now we just need to adjust the sharpness, and take some final steps. (You will not see the effect of sharpening on the small images presented here, so I left this one out, but you will see it when you are working on your high-res scans.) A word of caution: do not over-sharpen your high-res scan! It can happen easily, and -especially with grainy 400 ASA slides- might destroy the natural look of the scan – all you are actually doing in such cases is to sharpen the grain instead of the photo. That’s why I usually skip sharpening for such photos.

Step 7: Prepare for Web & Print

Up until now we have been working in AdobeRGB and 16 bit mode to preserve as much image information as possible during the post-processing. It takes longer and requires more memory, but the additional data pays off when the image is actually being re-calculated by Photoshop. However, if you want to actually do something with the image file (e.g. publish them on the web, or order prints from your lab), then you should convert the mode from AdobeRGB to sRGB and finally from 16 bit to 8 bit mode. And then, in a last step, you will want save the image as TIFF (for loss-free long-term storage) and/or as compressed JPEG. I recommend to save the JPEG at a quality setting of 9, 10, or 11 (in Photoshop), again with the goal to preserve as much image information as possible.

The resulting image has a size of 26.6 MB (TIFF) and 4 MB (JPEG, Quality 11). If you are curious about the final image: please feel free to download the JPEG version as compressed ZIP archive.

That’s it. You see: Getting brilliant scans from your slides is a lot of work but definitely not rocket science, really.

One Response to “Slide Scanning – A Step By Step Tutorial”

  1. Leo says:

    Good tutorial and quite helpful too. I had some old photographs, and was looking for a one-stop-shopping-site to convert all my unique memories to digital format. I research and finally wound up using <snip>. They offered me good slide scanning services and I got 100 percent satisfaction.


    [edited by: admin at 4:21 pm (utc) on Feb. 6, 2009]
    [edit reason] No URL dropping in the comments, please [/edit]