So I turned my bedroom into a camera obscura

This weekend, when I was supposed to be revising for one of my final exams on Monday, I had an itch that needed scratching.

Since moving into this house nearly three years ago, I’ve often thought that my bedroom would work well as a camera obscura. That’s the name for a closed box with a small hole at the end to let light in. The light from the hole is then projected onto the opposite end. It’s how a camera works, actually, and it works in a ‘box’ from the size of a matchbox pinhole camera, right up to a room or specially-designed domed roof.

I saw this done on a BBC documentary about photography a few years ago, and it’s been at the back of my mind ever since.

The theory is simple: the small hole acts as a lens, and as the light pours through, it is inverted and projected onto the opposite wall. You then get a ‘live’ projection of the world outside on the darkened wall.

And the box/room must be darkened – as close to pitch black as possible. With a small box, you’d use tape. For a box the size of a bedroom, you must black out all sources of light from the windows. I used bin liners, but you can use anything that will do the job.

The best thing about the setup is that the ‘lens’ is really just a hole. Literally just a 10p-sized hole, cut into whatever material you are using to black out the windows. I read some stuff about using an actual lens over this hole – presumably to sharpen the projected image – but it’s pretty clear without.

All the ‘gear’ I used was:

  • a roll of parcel or gaffer tape;
  • a roll of twenty or so bin liners;
  • a pair of scissors.

The bin liners weren’t ideal – they’re quite thin, and I had to double up the layers. Thicker garden waste bags might work, or you can buy a more expensive roll of thicker plastic, for lining ponds, for example.

Anyway. Once I had spent an hour or two carefully covering the windows and plugging any stray sources of light, I turned off my bedroom lights. The room was pitch black once my eyes had adjusted. I went over to the larger window and pinched the middle of the plastic, cutting a small hole. Immediately, light shone in. I looked over to the opposite wall, and was instantly blown away by what I saw…

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Crazy!

Due to Science, the image is, of course, inverted. This takes a minute to get used to, and makes it quite fun to look around at a familiar scene, trying to spot where it has ended up in the room. And because the image is live (for some reason, I half expect it to be static), the movement of the clouds and tree branches is quite magical.

It was a bright, sunny day, and my bedroom faces south east, and this makes for ideal conditions to make a camera obscura. It also helps if your room is painted a light, plain colour, with as few distractions as possible to break up the image. I removed most of the pictures and frames from the wall to provide as large a canvas as possible.

Purpose-built camera obscurae can be found here and there – I visited this one in Bristol about fifteen years ago and was very impressed.

The colours you see in the images above are a bit brighter than they appear in real life. That’s because they are long exposures – between 5 and 20 seconds, I believe, allowing the camera more time to absorb the colours and light.

As well as inverting the image, the hole ‘lens’ actually helps you to understand how camera lenses work. The smaller the hole (or aperture), the less light can get in, but the sharper the image. The larger the hole, the brighter the image, but the fuzzier it is. I experimented a little, holding up a few lenses to the hole – but nothing beat the hole itself.

If I wanted to take the metaphor further, I could’ve used a wall-sized piece of film or photographic paper, and created a print. My room would then have basically been a camera proper. Unfortunately, wall-sized photo paper and film is a little hard to come by, so I was happy to revel in the experience in person – as well as taking some digital snapshots.

An amazing result, and I’m so glad I gave it a go. It might also be the most extravagant and time-consuming form of procrastination I’ve completed to date. That’s something to celebrate. Now, back to revision.

Finally, this short video neatly  helps to show the whole process, should you be curious:

http://www.youtube.com/watch?feature=player_embedded&v=gvzpu0Q9RTU