How to Scan Slides Without a Scanner

Introduction

Do you need to scan thousands of slides but don't have a scanner? No problem! In this guide we'll explain how to digitize slides by photographing the projection screen directly, at zero cost and with results comparable to those of a professional scanner. Let's see how to proceed!

How to Proceed

For a long time our father archived our family memories on 35 mm slides. Since the oldest ones dated back to 1980 and were beginning to deteriorate, we decided to convert all the old slides to digital, for a total of about two thousand photos. The only problem was that we didn't have a slide scanner.

Having them professionally scanned would've been very expensive; buying a slide scanner didn't make much sense either, because it would have required a lot of time and was quite costly. We were sure there had to be an alternative way, and we were determined to find the right one.

They were memories of our parents when they were young and of us as children, and we wanted them to be as beautiful as possible. So we made several attempts to find out which method would offer the best results.

As a first attempt, we tried using a traditional scanner, with very disappointing results. There were also some more better models, but scanning them one by one would have taken far too long and we didn't want to buy a scanner at all.

Next, we tried backlighting the slide with an LED panel, and photographing it with a macro lens. The result wasn't bad, but doing it two thousand times would have been an enormous amount of work for such a mediocre outcome.

In the end, the solution that combined the best quality and speed seemed to be photographing the slides directly as they were projected. But how could we achieve the highest possible quality? After several tests, we present you our solution.

"Scanning" the Slides

The projector: for the projection we used our father's linear-loader projector, a Perkeo R2500 with a Zeiss lens, remote control, and autofocus. We weren't able to test other projectors, but the quality of the projection device will definitely affect the quality of the shots. We could recommend using a good branded projector with quality lenses, but given how hard they are to find, be happy with whatever you can get your hands on.

The projection screen: finding the ideal projection surface has not been easy. The panel must be perfectly smooth, because the texture of a classic projection screen becomes very noticeable on uniform areas of the photos, such as a clear sky. We considered using a white-painted metal panel, but the reflection of the projector lamp was visible. Online, someone suggested using a panel made from a specific type of matte Plexiglas, technically referred to as rear-projection material. Fortunately, since we work in an electronics shop, we had one available, but too much sharpness was lost.

After several tests, we found the ideal surface for projecting our slides: a sheet of 50×70 cm matte white high-weight paper, purchased from a print shop. We recommend buying several types of sheets, since they are relatively inexpensive, so you can choose the smoothest, most matte, and cleanest one. Try both sides, front and back, to see which gives the best results. Before buying, you should also check with your phone's flash that the sheets don't produce any reflection.

Camera Settings

We used a telephoto lens to avoid distortion and to position ourselves behind the projector. If you plan to use a phone, be sure to have a long lens or, at least, a good-quality digital zoom.

At first, we mounted a 90 mm macro lens. Later, we tried the Canon 70-200 mm f/4, without noticing significant differences in the results. We opted for the 70-200 mm for the flexibility of positioning offered by the zoom. The camera was set to manual mode with the following parameters:

• Shooting with remote control
• Manual focus
• RAW files
• ISO 100
• f/5.6
• 1/20 second
• Automatic white balance

The reason we use manual shutter speeds is that we're working with a DSLR camera. If you're using a phone or a compact camera, you can leave everything on automatic.

Even though choosing automatic white balance may seem like a mistake, after several tests we found that it provided the best results. Some slides had strong color shifts, due both to age and to the different types of film used. Automatic white balance allowed these issues to be corrected automatically and produced more consistent shots compared to a manual setting calibrated on the projector lamp. If you want more information about white balance, we invite you to read the in-depth explanation below:

What White Balance Is Understanding white balance and how to set the correct tonality for a perfect photo. Reading time: 11 min.

Camera and Projector Positioning

After taping the sheet to the wall, making sure it's properly tightened and completely wrinkle-free, we placed the projector on its stand about two meters, or six and a half feet, from the wall. The projection was very bright and sharp, with a long side of approximately fifty centimeters, or twenty inches.

The camera has been placed on a tripod, just behind the projector: we tried to stay as aligned as possible with the projected picture to avoid distortions caused by the slightly higher position so as to have a keystone distortion almost impossible to notice. The illustration below should clarify the positioning, even if it's very simplified.

We then adjusted the zoom to fill the frame with the projected slide. This step is extremely important to obtain a straight slide scan that fills the frame and will save you a lot of work in post-production.

Then came the boring part: load the slides in the first carousel, load it in the projector, press the advance button, press the shutter button, and after thirty-six shots change the carousel. Repeat fifty times.

Scanning slides without a scanner is a bit tedious, but we took the opportunity to calmly see the photos from our childhood, turning a monotonous task into something pleasant. We split the work over a few evenings after dinner, being careful not to move anything from one day to the next and gently loading the carousel to avoid moving the projector.

Fixing the "Scans"

As we briefly mentioned before, you could just leave the camera in full automatic; the results will be acceptable, leaving you with nothing else to do.

We're a bit of perfectionists, so we used manual settings and a little post-production. If you are as picky as us, continue reading; otherwise, you can directly jump to the next chapter.

After shooting, we noticed that a very small number of photos were poorly exposed or color-balanced, so we moved on to a bit of retouching.

Using RAW files allowed us to edit the photos without losing quality; if you don't know what RAW files are and how they are superior, we invite you to our page on the subject:

What are RAW files? RAW files: what are, what are used for, and what advantages do they offer in editing. Reading time: 8 min.

We opted for batch editing, which means we used the same settings, automatically applied to all the photos. The following list refers to Canon DPP software:

• Sharpness +5
• Saturation +1
• Contrast -1
• Shadows +1
• Lens distortion correction
• Lens peripheral illumination correction

Once the standard correction had been applied to all the photos, we quickly adjusted the individual RAW files that were too dark, bright, or wrongly color-balanced. Fortunately, there were really few; it was fast work.

We finally exported our "scans without a scanner" in .jpg, scaling the resolution to 3000x2000 pixels, because more would've been useless. Sadly, we can't write you a tutorial for your RAW editing software.

If you didn't shoot directly in .jpg, we recommend applying post-production using a photo-editing program; we love a free and powerful tool called GIMP. Click here for the official website.

To begin, you should apply automatic white balance and then increase sharpness by applying an unsharp mask. As a final step, you should correct the brightness and saturation of any photos that turned out too light or too dark. By clicking the links, you will open the corresponding pages we wrote on our blog about photo editing with GIMP.

Scanner-Photo Comparison

Before deciding that scanning slides without a scanner was an acceptable solution, we asked a local photographer to scan a slide with a professional scanner at medium quality. Below you can see a detail of the image, at native resolution, followed by our results:

By applying an unsharp mask to the photograph of the slide and using automatic white balance, as described earlier, we obtained this result:

Compared to the professional scan, our solution is slightly less sharp but also cleaner; the overall quality is a bit lower, but with a relatively small time investment the results are more than satisfactory, with a price of almost zero. Below, the full picture, with a highlight of the crop we showed in full res above.

In our case, it took about 25 hours of work, including editing, for 2,000 slides. In practice, that's less than one minute per photo, not to mention the joy of looking back at childhood photos we hadn't seen in years.

Below you'll find the link to download three slides at the full resolution of 3000×2000 pixels, so you can check the actual shooting quality. The overall quality is almost funny to look at, certainly nowhere near what modern photos look like.

• Slide one: Dolomite panorama.
• Slide two: maritime panorama.
• Slide three: architectural detail.

As you can imagine, the main purpose of this technique is not to achieve the highest possible quality, but to quickly scan many slides without a scanner, digitizing them and making our memories more easily accessible.

Conclusion

We hope you liked this page about photographing slides for digitization. Before saying goodbye, we would suggest you read our home page, with all the articles we wrote about Cortina d'Ampezzo.

If you want to thank us, you can read the page Support Us. If you only want to suggest a change, propose something, or just say hello, in the section Contacts and Info, you'll find all the ways to reach us.