Coffee + Salt + Overhead Projector = Interactive Light Graffitti at the BYOB (Bring Your Own Beamer) Party.

I wasn’t going to go the BYOB (Bring Your Own Beamer) Party, but changed my mind at the last minute.

While I’ve never done any light art previously, I decided that wasn’t going to get in my way, since you get in free if you brought a projector.

The other thing I decided wasn’t going to get in my way: I had lent my video projector to someone else for that very same party. Also, I am not much of a VJ or Video Mapper.

I thought of what else I had, and remembered that I have an overhead projector.  So, I decided to get low-tech, hands on and participatory.

First step: I took a clear plastic dish (a lid for my food processor tool case) and covered the areas of the screen that weren’t covered by the dish with tin foil. This stopped light leak.

Then, I looked around for something to fill the screen with. I looked in the kitchen cupboard, and found it: coffee!

I tried it out, and while the grounds made great lines and textures it also had a lot of gaps.

Back to the cupboard, and found the next thing: salt!

The mix of salt and coffee gave the perfect mix of graininess and not letting the light through.

(Flour was up for consideration, but if it starts to drift around it can be explosive. Not knowing what the space was going to be like, I decided to opt out for things that were decidedly NOT explosive.)

It turned out great!



People were first attracted by the smell of the coffee! Then, it was great to watch them figure out how they could doodle in the mixture and they light would show up on the wall 10 feet high. I never got tired of watching the wonder and joy on their faces. So many had great stories to go along with their experience.

It was great to let people participate directly.   I’ve been intimidated by the learning curve of video mapping, so it was great to give people some thrill of being able to get their ideas up.

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