Introduction: Building and Testing the Optical Apparatus From Tim's Vermeer

By Attoparsec
About: A kinetic sculptor known as Fish. He is currently making a slow, terrifying transition from computer professional to full-time artist.

Earlier this summer I watched the documentary Tim's Vermeer, which follows Tim Jenison as he tries to recreate a Vermeer painting using an optical device known as a camera lucida. This was basically a mirror at 45 degrees, allowing you to see both the original photograph (or a live scene, with the addition of a concave mirror) and the same area of the painting right next to each other. This would allow for direct comparisons of size, shape and color.

I was fascinated but not entirely convinced. It's easy for a documentary to spin things however it wants, after all. There would only be one way to see how well it really worked -- try it myself! I decided to try the simplest form of the device, working from a photograph instead of a live scene.

There wasn't a lot of information I could find online, though. I found a podcast interview with the eponymous Tim, who recommended using a first surface mirror. I happened to have a couple of those, taken from a grocery store checkout laser that I disassembled in grade school. (They can also be ordered from a source such as Edmund Optics. You'll want a rectangular mirror at least a couple centimeters on a side.)

I first experimented with holding the mirror in a simple adjustable clamp arm. This was not successful. The clamps didn't hold either end very firmly, allowing the mirror to shift at the slightest bump. Worse, it was almost impossible to finely adjust its position. I decided to make a serious mirror mount before continuing.

Step 1: Making the Mirror Mount

I borrowed a microphone stand from my roommate which immediately solved most of the problems of the previous arm. It was solid and could be adjusted easily. All that was needed was a way to mount the mirror on the end of the boom. I found a camera mounting bracket online with an adhesive plate to which the mirror could be stuck. Perfect! The other side had a standard 1/4"-20 camera mounting screw, so all that was needed was a sleeve that could be clamped firmly to the microphone boom with a threaded 1/4"-20 hole in one side.

Note: Since I have a lathe in my shop, I used that. You could also get some thick pipe or tube stock that fits over the microphone boom. Or even drill out a chunk of wood! Just because I got all fancy, that doesn't mean it's the only way.

I found a 2" chunk of 1" stainless steel hex stock in my scrap bin. Utterly overkill, but I couldn't resist using it. I chucked it up in my lathe and drilled it out first to 1/4" and then to 5/8", which was the diameter of the boom. I also had to bore it out to a couple thou over, to get a nice sliding fit. Finally I bevelled the edges because I could, and I think bevelled hex stock is one of the prettiest things around.

Using my height gauge (again, total overkill, but if you don't practice when you don't need to, you won't have the skills when you need them) I marked the positions of 3 holes: 1 for the mirror bracket and 2 for thumb screws to lock it in place. In retrospect, these should have been on adjacent faces instead of on opposite sides, so the thumb screws wouldn't project down and get in the way as much. I drilled the holes with a #7 drill bit and tapped them to 1/4"-20. Done! With the mirror attached to the camera bracket, and that screwed into the sleeve, and that clamped onto the arm, I had a solid, adjustable, stylish mirror mounting system.

Step 2: First Attempt

For a first attempt, I cropped my favorite picture of Isambard Kingdom Brunel, printed it out and mounted it upside down in this adorable little easel I found. I moved the mirror into position, so I could see either the original or the painting as I moved my head back and forth. I sketched out the rough outline in pencil, and I started painting.

And it worked... kind of. I did manage to get a recognizable painting out of it, though, which is quite something as it was my first time painting or doing any kind of representational art in roughly 20 years.

But there were several problems:

  • The painting was a mirror image of the original. I should have printed out the photograph mirrored to begin with.
  • I had the mirror set so close to the painting surface that it was hard to paint underneath it.
  • The painting was squished vertically relative to the original photograph.
  • As I moved my head side to side, the reflected image shifted relative to the painting, making it very hard to keep things lined up.

More work was needed, obviously.

Step 3: Improving the Set Up

I thought about the problems and realized there were some easy ways to get the angles right. The mirror needs to bisect the angle between the two planes so that the distance to the original and the painting from the mirror's edge is always the same. Doing that is a lot easier if they are 90 degrees apart, so I mounted the photograph vertically this time. Then it was easy to set the mirror to 45 degrees using a combo square.

Next I aligned the mirror along the dividing line between the two planes. You can test this fairly easily if you print out a second copy of the photograph you're painting. (See the attached video for a quick demonstration.) Mount the mirror-imaged one upside down as you normally would, then place the normal version upside-up where the painting will be. Look down past the mirror, and adjust the lower copy so the two line up properly at one point. Now move your head forward. If the mirror is in the correct location, the two images will stay lined up. If the image in the reflection moves farther/gets bigger, then the mirror is too close to the original, and vice versa. Adjust the position of the mirror until they stay lined up.

Keeping the copy lined up with the reflection, test that the mirror is parallel to the painting in the other axis by moving your head side to side. If the images don't stay aligned, adjust the mirror to make sure it is parallel.

Step 4: Second Attempt and Conclusions

With the improved set up, I tried using the device again. This time I used the iconic picture of Goddard standing with the first liquid fuel rocket engine. The results were much better! The optical stability gave me a lot more confidence, and with the mirror so much closer to my face I found that diffraction effects very convenient. Right along the edge you can actually see both photograph and painting at once, with a smooth fade from one to the other.

Conclusion: The camera lucida as seen in Tim's Vermeer does work, and it isn't too hard to set up. It makes matching shape, form and tone almost trivial while painting. It doesn't mean you don't need to learn good painting techniques, though! You still need to learn how to blend paints and control the brush. But it does provide a much tighter feedback loop, so you can see what works and what doesn't much faster. I hope to continue my experiments, moving into using color and then working from a live scene.