Drum roll please. The world has been waiting for me to invent this. Here it is and it's even easier and cheaper than Andre's and Denis's shutters.
Simple! Affordable! It's all in the wrist action. I can get 1/125 second with my shutter. Used it today on the Eastman 11X14 with the Plastigmat lens.
Now in case you want to fuss that my slit that passes in front of the lens is V shaped and doesn't distribute equal amounts of light over the film surface, I'll remind you that 90+ % of all the film that's been exposed in the last 100 years was done just that way. That's how movie camera shutters work.
Detailed instructions:
1) Firmly grip 2 5X7 film holder slides with about a 20 degree angle left open between them.
2) Place the lower one over the lens. It's OK to touch the lens at this point. Pull the film darkslide.
3) Move the "shutter" just in front of the lens so it doesn't touch.
4) Pass the slit in front of the lens and stop when the upper holder is covering the lens. It's OK to touch the lens at this point too.
5) Replace the dark slide.
6) Exposure control is by how 'fast' you flick your wrist. I was after 1/4 second and moved fairly slowly. In fact I went down once and up once. 2 1/8th second exposures if you will.
7) Need 1/250th? 1/500th? Simply close down the slit to 10 degrees or 5 degrees. I'm still working on the flash sync
Taking orders for the Jim Galli shutter. Write your address on a $50 bill and mail it to me. I'll get your shutter mailed right back to you.