Thornton Picard Shutter: Curtain Length?

[alanbutler57]

I recently purchased a shutter in need of repair, but the curtain is missing below the window. Does anyone know the needed length for this section (I assume it is a multiple of the open window length). I've purchased material I think will work and have scoured the internet. Any other information on how these function is also welcomed. I'm just getting started with large format as a hobby.
Thanks,

[Pete Watkins]

Contact Ian Grant, he's the expert!
Either here or on APUG.
Pete.

[Paul Ewins]

I wrote a tutorial for rebuilding these a few years back and you can probably calculate it based on the pictures I have there. I can't give an absolute answer because the TP shutters came in different sizes. Anyway, have a look here and come back if there are more questions:
http://www.paulewins.com/old_site/resources/tp_shutter.htm

Paul

[alanbutler57]

Thank you both, I see that Ian works on these in Turkey, too bad the shipping makes it impractical to send this one to him! Paul, I had arrived at a similar conclusion looking at your very well written article, it looks like your curtain had an aperture of ~65mm with an overall curtain length of around 10", that is the ratio I'm going to start with.

I'm also thinking about incorporating a slot between the shutter and lens to hold Cokin "P" filters, not sure how common that is, might be better to put the slot between the shutter and lensboard?

[IanG]

Alan, I'm in the UK at the momenent, although I will be in Turkey for in 10 days or so for a short stay. I have materials & tools etc in both locations :). I restore TP shutters regularly and have a good supply of shutter cloth, enough for rather a lot of TP shutters :D as I've just had to make up a large lenght for a 7x5 Graflex shutter (6ft x 8") and have plenty left over.

I always make my curtains longer than actually needed and trim when I fit them, first to the top roller the shutter must be just closed when this is un-wound, then when this is dry I wind up until the bottom edge of the shutters aperture is just on the top roller then glue to the tensioning roller.

One thing to watch is the shutter's window aperure's not the same with all TP shutters it can also depends on the position of the lugs on the main gear. These lugs control the position of the aperture on the T setting (also used for focussing). PM if you need help.

Ian

[IanG]

You run the risk of fogging if the Cokin filter's between the lens & shutter, which also definite;y rules out between shutter and lensboard that area must be light tight.

Better to make an adaptor to fit to the front of the lens.

Ian

[alanbutler57]

Thank you Ian,
If this restoration doesn't pan out I may troll ebay for a shutter in the UK and arrange shipment to you directly. Yes, fogging would be an issue vis a vie the filter slot, I'd thought to wrap it with velcro to maintain light tight integrity before placing film into the light path, the main purpose would be to compensate when using tungsten fresnels (a favorite of mine) with color film. While I shot medium format for around 20 years before going digital 10 years ago, this is my first step out into LF, so I'm a little cautious stepping off.