Can I scan slides with my phone?

I recently blogged about my experience scanning film negatives with a popular mobile phone app. The results were unusable, but maybe I was expecting too much. Scanning and converting film negatives is one of the most challenging things we do in our studio, so I decided to try the same app to scan slides instead of negatives.

I used the same professional film holders and light sources, because I wanted to ensure we got the best possible results and most realistic comparison. For the mobile app I used the latest Apple iPhone and for the camera scan I used a Canon professional DSLR. 

I scanned several Kodachrome slides which are known for their high quality and vibrant colors. On the left is a scan with a popular mobile app and on the right is a camera scan of the same slide with the same film holder and light source.

Without seeing the original slides it might not be obvious which scan is more faithful to the original, but I’ll point out a few details that make the camera scan much better than the mobile app scan:

1. Colors are faithful to the original, but washed out in the mobile app scan
2. Image is flat in the camera scan, but distorted and stretched in the mobile app scan
3. The camera scan captures the entire image area, but the mobile app scan crops some of the edges with no way to recover what was lost

The differences become even more obvious when you zoom in and compare the details:

1. The camera scan on the right retains all the details of the slide, including the woman’s face and even the branding on the soda can. The phone scan on the left is blotchy and doesn’t retain much detail.
2. The camera scan captures more than 4x the number of pixels as the phone app, which makes it possible to print, enlarge, and restore much more than the phone scan.

If you think it’s unfair to use just one example, I completed the same comparison on many other slides. Here’s another slide where an initial comparison of the phone scan and camera scan don’t look that different.

But when you compare the digital images with the original slide, two things jump out:

1. The phone app capture made an image much lighter and more vibrant than the original, while the camera scan is faithful to the original color and exposure.
2. The mobile app has significantly lightened the corners of the slide, which have a dark vignette in the original. I’m not opposed to editing and improving digital images, but we don’t use or recommend apps that gives me no way to customize, limit, or reverse the automatic edits they make.

When you zoom in and compare the images there are even more alarming differences:

1. The camera scan retains all the original detail in the faces, but the mobile app scan renders them very blotchy.
2. The red jacket and pants on the woman on the right are full of dark artifacts in the mobile app scan.
3. The shadows in the mobile app scan have been lightened in an extreme and unnatural way. Shadows in the camera scan are black, which is how dark shadows look in real life.
4. The resolution of the camera scan is more than 4x the resolution of the phone app. This captures all the original detail and gives you the freedom to restore, reprint, and enlarge your memories.

Conclusion

When I used the mobile app on my phone the initial capture looked okay, even if it was a little overexposed and oversaturated. But when I transferred the files from my phone to my computer and looked at them at actual size instead of on a 5″ or 6″ screen, the poor image quality was glaringly obvious.

The capture speed of the mobile app is pretty fast and the automatic cropping is reasonably accurate, but the image quality is horrendous. I’ve been testing these apps for years, hoping that they’ll get better. Unfortunately, I’ve seen no improvement in image quality and consider them a gimmick at best. They claim to offer “magic” and “clarity”, but these sample images speak for themselves.

If you’re going to take the time to locate, sort, and clean your slides, don’t skimp on the actual scanning. Do it right the first time and get quality that you can enjoy today and your grandchildren will appreciate in the future.

Interested in working with Chaos to Memories?

If you’re near Chicago and ready to get started, come visit our Wheaton Studio Monday – Friday, 10-5. Please bring your memories with you.

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