modifying film holders

[Dan Dozer]

I have been developing plans for constructing an 8 x 20 camera and have a question concerning film holders. Has anyone out there tried to modify and join two 8 x 10 holders into one 8 x 20 holder? I have given it a lot of thought, and think that I might be able to make it work with a pair of older wooden holders. It should be a whole lot less work than building new holders from scratch and obviously a lot less expensive than buying new ones. It would of course require constructing new darkslides. If anyone has tried this, any thoughts and experiences would be appreciated.

[Hugo Zhang]

Dan,

I have 5 holders custom made for my 10x20 banquet camera at this moment by a small shop in China. Three holders will be of 9 1/2 x 19 1/2 and 2 holders will have inside measurement of 8x20, a hedge against possible lack of odd size films several years down the road. The holders will be made of mable and the darkslides will be of cabon fiber. I will have them by late August when I return from China. I will show them to you. If making your own holders cause you too much trouble, you might find a quality product at affordable price. I have not seen the holders yet, but I find their cameras quite impressive, much better than Shen-Hao.

[Ralph Barker]

I'm not a ULF shooter, Dan, but as a woodworker, I have a hard time imagining how to make the joint strong enough. I'd think the center septum would need to be one piece, as well as the wooden frame edges along the long dimension.

[Brian Vuillemenot]

I"ve heard that Keith Canham makes 4X10 holders by cutting 8X10 holders in two, so perhaps it may be possible to weld together two metal 8X10 holders to make an 8X20.

[Dan Dozer]

Hugo - as you know, I'm eagerly awaiting the chance to see your 10 x 20 as well as your new film holders. I agree, from seeing the pictures of the camera being manufactured in China you sent me, it looks very promising as a new ULF camera maker. I'm also curious about the cost of your holders coming direct from china as opposed to purchasing here in the US.

Ralph - I'm a woodworker as well and have given this a whole lot of thought. My plan is to cut a dado the length of each holder with a router on their long edges and recess in a long aluminum strip on each side to stabilize the two holders. Obviously, I would use the front end of one holder and the tail end of the other. There appears to be enough space to cut a slot for an aluminum strip 1/8" deep x 3/8" wide x up to about 18" long and get plenty of screws in to secure all together. With one aluminum strip on each edge of the holders and enough screws, I think it just might work. The center septum will likely have to be replaced with one that would be the whole length, but I'll have to wait until I dismantle a holder to really find out if my plan is possible. The center septum may be a whole new problem (challenge) that may doom my plans. As one woodworker to another, do you think this sounds like it's destined for failure or a possible success?

Brian - While I am a woodworker, I'm no metal worker. That is why I would need to use the older style wood holders.

[Ralph Barker]

. . . do you think this sounds like it's destined for failure or a possible success?

While it might be possible to reinforce the joined edge with some sort of spline along the length, Dan, my impression is that may not be enough. The rigidity of the holder, it seems to me, is a combination of the wooden frame and the strength added by the one-piece septum. With a joint in both at the same spot, I think you'd lose that combined strength. It might be far easier simply to construct the holders out of fresh materials.

Additionally, I'm not sure that the dimensional specs for older wooden 8x10 holders would match those of current ULF camera designs. Although my impression is that there are no formal standards for ULF holder specs (as there are for modern 8x10 and smaller holders), you probably want to conform to at least one of the "commercial" designs, so your camera and the holders will match something commercially available, even if not supported by an ISO standard.

[Dan Dozer]

Hi Ralph,

Couple of additional thoughts -

I currently have a Kodak 2D 8 x 10, and the old wooden Kodak film holders and more modern Fidelity holders both fit. However, my experience with my old Eastman 5 x 7 is that the older holders aren't always interchangeable and the newer holders don't really fit it. My thought is to construct the camera back the same as my Kodak 2D as far as details and dimensions go, and therefore both the old Kodak holders and "today's" holder styles should both work. Initially, I thought to construct my holders from old Kodak holders rather than something like Folmer.

With my old style Kodak 8 x 10 holders (I have three), the center septum does not appear to add a lot of additional support to the rigidity of the holder. It is constructed out of a thin almost cardboard like material. However, nearly any material if it is connected adequately to the four holder sides will add a surprizing amount of structural support (back to my structural engineering days in college) and help maintain the squareness of the holder. I don't think that just taping the two center septum pieces together would work adequtely and may not hold the film flat. Therefore, replacing it may be the only option. It may be that if I replace it with a more rigid material (like aluminum or plastic), it will work better to firm up things.

Whether or not splicing the two holders together will work will only be known by testing. I first plan on constructing an 8 x 20 test frame similar to the holder size and dimensions using my splicing idea to see if it is strong enough or not. That should tell me if it will work or not.