Some Large Format Experiments

In spare moments, while the fine weather has continued, I've been continuing my experiments with large format paper negatives. Developing them in film developer rather than regular paper developer has proved to be a very promising experiment. More about that in a later post, I hope.

Meanwhile, I've been tinkering with the cameras themselves. My old Linhof press camera is proving to be a useful test rig for trying out a few of my ramshackle assortment of discarded lenses.

One of the minor faults with the Linhof has been the broken ground glass screen, split right across from side to side and only held together by the spring clips in the camera back. It still works, but it's distracting to look at. The prompt to do something about it came when a student gave me a 12"x 16" piece of picture-frame glass left over from a studio shoot.

Having no better use for it, I cut some pieces to fit the back of a 5"x4" camera. I then got hold of some lapidary grit and decided to have a go at making my own ground glass screens. I found an excellent online explanation of how to do it by an American large format photographer, Dick Dokas.

His instructions were simplicity itself to follow, and  I was thrilled with what I was able to achieve in ten minutes or so of grinding the two pieces of glass you can see in the foreground of my photo. A light sprinkling of grinding powder and water produced a very fine bright translucent finish, similar to fine tracing film. I started off thinking I would use the cheap rubber suction dent-puller (seen in the background) to hold the top piece of glass, but that was completely unnecessary. Simple finger pressure on the top piece of glass was all it needed to keep it moving.

Another problem I've been pondering is how best to control exposure times with some of the lenses I've wanted to experiment with. Some have variable apertures, but none have shutters, so some sort of independent shutter mechanism is needed. Having studied the problem, the solution (I hope) arrived yesterday by post from the USA in the shape of a Packard Shutter, bought from an eBay seller in Floyd, Virginia.

My example is clearly a vintage item, though they're still manufactured by the Packard Shutter Company in California. It's clear that there is a dedicated army of Packard users among large format photographers (predominantly in the US) judging by enthusiast webpages and YouTube videos. In its present form, my shutter is operated pneumatically by a rubber bulb connected by tubing to the piston you can see on the right in the photo. I can see why these shutters have their fans, they're an elegant and simple way of controlling exposure and a classic example of nineteenth century technical innovation.