Making the perfect pinholes

I'm planning on doing some Solargraphy in 2011. For that I need a pinhole camera. Or to maximize my chances of actually ending up with something usable multiple pinhole cameras.
So I started to collect every single can, tin and box I could get my hands on. Round, square, long, tall, short you name it. I even have a 8 sided box, but I am unsure what to do with that.

Anyhow so yesterday I made some pinholes. 12 to be exact. These were the materials I used.
- Fine sewing needle
- Scotch tape
- Disposable pie tins
- Sanding paper (I used a Scotch Brite sponge)
- Scissors
- Magnifying glass
- Note pad
- Sharpie
- Scanner
- Patience

First thing I did was to cut up the pie tins. You want to end up with 2x3cm pieces or something small (but big enough) to handle. Then I grabbed my needle. I wound some Scotch tape around the needle to make it a little thicker so it's easier to turn when drilling the hole. Next I took the notepad and a piece of my freshly cut tin pieces. Took the needle and pressed gently with one finger (while turning it also) through the tin. I pushed the needle through from 1/5 to 1/2 the size of the point of the needle itself. Took the needle out and turned the piece around. Took the sponge and smoothed off excess metal on the back. Looked at it with the magnifying glass. Repeat this a couple of times.

But how can you measure the size of your pinholes? Well do this. Grab your scanner and put your piece of tin on the glass. Leave the top open because you want the light from the scanner to go through the hole but be sure the tin touches the glass where the pinhole is (you can always use some tape to hold it down). Put you scanner on the highest available resolution (I scanned at 12800dpi) and scan at 100%. Open this image up in Photoshop and change your unit settings to millimeters. You can either use guides to measure your pinhole or use a selection. I think guides are a little more precise. Now write down the 'gauge' of your pinhole on the tin and maybe number it as well.

That's it really. Easy. But remember, patience is the key.
Now that I have a whole selection of pinhole gauges (ranging from .11mm to .81mm) it is time to build camera's. But that is for another post.