Tips & Tricks – April 29, 2019
Scanning with your Smartphone
My emphasis this year has been on the convenience and impressive capabilities of today’s smartphones as cameras. I began my discussion by demonstrating how small and convenient smartphone accessories are as well. In a 5 inch soft bag I had a tripod, remote controller, 6 additional lenses (from telephoto to fisheye), a backup power device, and room for a 2 Terabyte pocket hard drive and Wi-Fi controller for exchanging images. I then pointed out that my smartphone was also a picture viewer, tv, movie viewer/recorder, post office, radio, audio recorder, health advisor, word processor, GPS, calculator, tool for artists (graphical, musical, writers, etc.), games machine, security system, collection of documents (magazines, books, sheet music, news articles, etc.) ,and the list goes on.
As photographers we are interested mostly in the uses of the powerful cameras we have in our device and the work they can do. One of the jobs they can do which tends, I think, to be underappreciated is the scanning of our precious images already captured on prints, slides or negative film. That is the role I chose to address this time.
The most serious challenge in scanning prints is the fact that the surface of the print reflects unwanted points of light from the surrounding sources of light and those reflections are recorded by your camera. There are some clever lighting techniques to counter this, but they can be time/money consuming and difficult to get just right. Google has come up with a clever app called Photoscan that addresses this problem for smartphones straight on. It works by guiding you in taking a set of images, some of which should be at a slight angle avoiding the same glare as at other angles. The software stitches the images together to try to eliminate the glare. In my initial trials I was surprised at how successful it was, and how sharp the images were, given that the images were taken hand held. I do advise that you use a light source off to the side of image. I used two, one on each side. If you have a single straight-on light source, it is less likely the camera will capture any images in which the reflection is in a spot not visible in other images, and thus fail to eliminate it. Try out this free app. You may be as impressed as I was.
For slides and negatives you will be backlighting your material, so reflections are not the issue, and Photoscan will produce unwanted artifacts. If you use this app, turn off the anti-reflection option.
One thing you will want to do before scanning loads of negatives is to look at them and decide which ones deserve archiving. This is much easier if what you see when you look through your viewfinder is a positive instead of a negative, and if you can enlarge the image at will to see detail.
Fortunately you can do both of the latter tasks by changing a setting on your smartphone. In IOS devices (IPhone/IPad) this is how it is done:
- Go to Settings
- Then General
- Then Accessibility
- Then Display Accommodations
- Turn on Invert Colors
If you want the magnifier option:
- Go back to Accessibility
- Choose Magnifier
For normal use of your camera later, you will want to turn off the Invert Colors feature above.
This lets you look over your negatives and make some decisions.
To actually use your phone for scanning slides and negatives you can do the following:
You need a soft/out-of-focus light source. I use my Ipad with brightness turned up full and a free app called Softbox. This produces a full white screen for my purpose. However the tiny, almost imperceptible grid of the screen is clearly visible to your camera at close range. Therefore you must raise your slide/negative at least a sixteenth inch above the Ipad screen. You could use some foam core, some erasers, etc. to support the slide. Easiest would be a clean sheet of glass, either thick enough itself or supported just above the screen. I support my camera on a tripod facing down, and just place the slides one by one in position and snap the picture. Results have been very good. Depending on how close your smartphone’s camera will focus, you may need to resort to your dslr and lose the clever software help of the smartphone in the capturing process. In any case, well worth a try.
I really don’t know if this process matches the quality of dedicated photo scanners exactly, but for ease/speed/cost it certainly appears to be superior.
Best of luck with your scanning.
Have a great summer.