The Lightboard

Every now and then a new technology comes along that’s worthy of note.  Much of what we see are incremental improvements – smaller, cheaper, faster – or new ways of achieving old results (video over IP).  But it’s good to acknowledge novel products or techniques that establish themselves, and one of these is the lightboard (or learning glass).

We’ve all seen images from old movies, where someone is marking up a map printed on glass by standing behind it and writing backwards.  It takes a special skill, but solves a problem; the writer isn’t blocking the view.  But the technique remained somewhat of a specialty for many years, as it took a lot of effort to learn, and there was little mainstream need.  More recently though, as many of our lecture halls and teaching spaces have moved to video, there’s been renewed interest.  How then do we achieve this in everyday practice?

There are many resources online; this one, from Michael Peshkin at Northwestern University, https://www.lightboard.info/ is particularly good.  In it, he identifies the many elements that need to be addressed.  The most obvious is achieving backwards writing without years of practice, and the simple solution is an additional mirror.  The instructor writes normally on glass, and is viewed by a camera through the glass.  The image of course is backwards, and so we add a mirror in front of the camera itself.  Twice reversed, the image comes out right-reading.  We can then display this to the classroom or record it, as needed.  The added mirror takes space, and electronic image reversal (in the camera, recording device, or outboard accessory) can sometimes be substituted.

Less obvious are the lighting elements.  The glass needs to be edge-lit so that the handwriting glows brightly; a drymarker pen on un-lit glass is scarcely visible.  And not only have we captured the handwriting, but we’ve captured the instructor as well, who needs to be illuminated from the front, rear, and often above.  We need a black background to remove any visual distractions, and to maintain good contrast for the instructor and handwriting.  It can become a small television studio.

The lightboard itself has become a product you can find online, and I saw the other day a packaged teach-from-home system that incorporates one.  While not yet mainstream, the lightboard is here to stay, and should be part of any designer’s toolkit.