I'd like to make an ABS wetplate holder for my whole-plate cameras but have run into a couple design problems. If you have a whole-plate camera (or reducing back), I'd like to compile some measurements of the rear box to aid designing a couple pieces.

I have 3 different whole plate cameras, an Eastman #2, a ROC Universal, and a ROC Carleton. I also have at least 4 different-sized plate or film holders in that format!

I've read several posts on APUG and the Large Format Photography Forum about the lack of standardization for this format, both in the past and present day even with new holders coming from Chamonix, Ebony, Lotus, S&S, and AWB. It sounds like a somewhat standard t-distance has evolved taken from the ANSI 8x10 standard of 0.260" but the modern variance runs between 0.260" to 0.300" from what I can glean from forum posts. I just measured an old Eastman plate holder with film sheath and get about 0.300" to the sheath surface. I have also discovered that not only are the holders different widths with different rib/light baffle designs, but the camera rear box dimensions are not the same between the cameras I own.

I'd like to attempt making a wetplate holder for the whole-plate format but face the dilemma of where to put the focal plane due to the different t-distances and, more importantly, my amateurish machining skills and tools. There's no way I can presently stuff a rigid darkslide and set of plate supporting corners in little over a quarter-inch. Half-inch, maybe. As a result, I've decided the path I'm going to take is to make my own adapter back and set the focal plane distance where I can have a reasonable chance of success constructing the holder by making it asymmetrical compared to normal film holders. I don't need a septum (or plate support corners) exactly in the middle of the holder since these things are going to load from the back, have a door, and only need a single darkslide channel.

It seems the current 2 or 3 wetplate camera manufacturers are so busy that they no longer wish to make adapter backs. Justifiably, they would rather spend their time crafting entire cameras rather than retrofitting those made elsewhere. And to date, In Camera Industries' recently introduced wetplate holders are manufactured only to fit the common modern formats of 4x5 and 8x10 (with 11x14 on the way). Lund Photographics does make whole-plate, half-plate, and 10x12 plate holders, but these are earmarked for older dryplate cameras and as such, have slightly different design considerations than a wetplate or film holder does. As a result, there seems to be a great resurgence in wetplate collodion occurring with more demand for new equipment than there are suppliers, and whole-plate photographers lacking any choice at all other than using a larger format camera with reducing insert.

I wonder if some sort of universal adapter back made out of ABS could be designed to fit different cameras yet still use the same holder? Not only would this help those wanting to do wetplate in historic size cameras, but such a scheme would be a way to keep any camera safe from silver nitrate stains and corrosion. I think I have such an adapter back worked out for my particular cameras, but I wonder if there is a much wider variation considering all whole-plate cameras.

If you are using a whole-plate camera I'm hoping you could measure the rear box and let me know what the dimensions are so I can get some idea of the range adapter backs would need to cover. Here's what I have so far for my cameras:

The rear box of the Eastman #2 camera is 10” square with a rabbeted light baffle 1/8” deep and 1/4” wide (i.e., the 1/4” thickness of the box stock).

The ROC Universal and ROC Carleton cameras have rear boxes 10 3/16” square with similar light baffle to the #2 Eastman.

What size is yours?