Search:

There is an app for that.
http://iphone.ambertation.de/lightmeter/
http://www.appstorehq.com/lightmeter-iphone-57542/app
Only works on iPhone 3GS.
(Pictures taken with older models don't have...

It depends on the layer blending mode you choose.
Normal, Dissolve, Darken, Multiply...

Looks like the instant film was not flat.

Once I attached a laser pointer on a DSLR and got the camera take picture of the laser point at a distance at a various shutter speeds.
I did that mainly to see the effect of mirror lock-up. I found...

I heard it's a patent issue.

My copy of coated Zeiss Jena Tessar 135mm seems to be much more prone to flare than Kodak Ektar 127mm.

Is this normal with this Jena Tessar?

Zeiss Jena Tessar 135mm f/4.5...

Here's the interview
http://www.cbc.ca/spark/2009/01/full-interview-andre-bosman-on-the-impossible-project/

The impossible project
http://www.the-impossible-project.com/

True..
I just happened to have a few of them.
They are simply two pieces of curved aluminium sheet put together.

You could use Polaroid Cold clip too.
http://upload.wikimedia.org/wikipedia/commons/thumb/6/68/Polaroid_cold_clip_193_IMGP1860_WP.jpg/451px-Polaroid_cold_clip_193_IMGP1860_WP.jpg

I've been taking...

I'd use light meter.

Take a light reading
Put the polariser over the probe
Take a reading again
Compare two readings.

I think you could use your digital camera too.