Wednesday, 12 August 2020

Using a phone photoscanning app to capture old documents

When you work with old documents and photographs, not to mention ephemera such as labels and packaging, sooner or later you need to make a copy.

Being an utter geek, I've both a flat bed scanner and a film and slide scanner at home, which means I can scan most things, and at the Dow's Pharmacy documentation project I use a little Nikon camera to photograph artefacts. The only thing I can't so is  photograph or scan books, but I do have half a thought to make myself a DIY book scanner. Or perhaps not - basic book scanners are remarkably cheap these days:

But sometimes, when you are out, you come across a photograph or document that you want a copy of. You can't take it home to scan, so what to do?

The obvious solution is to take a photo with your phone, but you then end up fiddling about afterwards tweaking and straightening the image.

But over the last few years, various scanning applications have appeared, initially with the aim of allowing you to easily and accurately scan invoices and receipts, but clearly you could use them to scan anything.

So how good are they?

Well I did some experiments using the Google Photoscan app on my iPhone (it's an iPhone 8, so the camera is nothing remarkable in terms of capability and resolution).

First of all, I scanned a page from an old notebook, and certainly I got a nicely lined up and legible image:

Now we have a copy of the Compleat English Gardener which belonged to J's great^n grandfather who was a market gardener in Barnard Castle in the 1810's. I took a photograph of page 9 and also scanned it with the scanning app.

(top: iphone photo app :: bottom photoscan app)

The photographic image is more realistic than the scanned image, but the scanned image is perhaps more legible, and has got rid of the shadow of my chair. What it does show is that photographs can be perfectly usable, but you might want to use the scanning app to guarantee an accurate image.

I then decided to compare how it handled photos. I've a picture on my pinboard that was taken of us by a photographer friend of ours after Christmas lunch in 2003. Despite showing how depressingly young we looked compared to now, it's a nice test example as it was taken on a reasonable quality Olympus SLR on standard Kodachrome and processed in an automated film lab as opposed to any clever stuff. Despite being taken by a professional press photographer, it was taken on his everyday camera and treated as an ordinary fun picture.

(top: scanning app :: bottom: flat bed scanner)

The scanned image is certainly better, but again the image taken with the scanning app is perfectly usable though a little bleached out - better lighting may help here)

So what do I think? - for documents it's certainly more accurate out of the box and gives more consistent results than simply photographing them. It also does a reasonable job of photographing images, but not to the quality obtainable from a proper flatbed scanner. 

Undubtedly, dedicated equipment will give better results, but where this is not possible, using a photo scanning app may give better and more consistent results than simply using the camera app. As always your mileage may vary and more recent phones with higher resolution cameras may give better results. 

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