Should have said help with the bladder on my Thornton Pickard shutter which I've just restored.

The bladder is inflated by a tube connected to a rubber bulb which inflates the bladder when sqeezed.

The bladder now leaks, and is rock hard, it's not man made and appears to be organic in nature, most likely some part of an animal or fish.

The bladder on the bottom right in the photo goes in the center of the shutter under the tab which it lifts and allows the shutter to fire as it's inflated. I need suggestions on how to make a new one, I've tried using a piece old bicycle inner tub but that not very practical.

Apart from this the shutter is now working perfectly, despite being sold for parts on Ebay, the shutter cloth was badly creased had a multitude of pinholes, there was no cord to cock the shutter and the brass & woodwork tatty. I ironed the shutter after removing a flaking covering, re-blacked it with black acrylic paint and it's now totally light tight but flexible, it requires very little effort to re-cock the shutter. I still need to determine the exact shutter speeds, it has two options depending on how many turns of the spring are used to tension it, as well as T.

I've fitted an early Ross symmetrical lens SN 2197, f8 - f64 approx 300m/12" which is marked as covering 8"x5"