View Full Version : Half-Plate bookform holders?
Does anyone have half-plate bookform holders?
I have an English style half-plate Japanese camera that I use with 4x5 and 5x7 backs. I have the original back for half plate but no bookform holders for it. I have no idea what a bookform holder looks like, otherwise I would try making some just to try using the original back.
I would appreciate photos of these holders and description of moving parts and function from anyone who can provide these.
You will need to make sure the following are present:
1. Dimensions fit your half-plate format
2. Grooves on either side of the book form hold the holder in to the camera back fit
3. Brass closure tabs work
4. Metal spring plate in the middle of the open book form is intact and in place
5. Cut down masks (may or may not be present
6. Glass sheet/plates are present (usually a bonus nowadays0
7. Moving parts are either brass or adhesive tape hinges.
The book forms open out like a book in the middle spread and the emulsion plates loaded in easily. Alternatively, film using simple adhesion principles are fine. Ole uses jam. I've discovered corn starch with water, which mixes up consistency very well and is less sticky.
I've also just had 18 glass plates cut from left overs which cost me nothing - will load the films onto, or to spread liquid emulsion over.
Best of luck.
PS - it's much easier purchasing second-hand book-form holders - they do surface from time to time. Someone sold me one on this forum but I've forgotten to check what I was supposed to be doing with it.
Thanks for the tip, Rob. I'll be verifying dimensions in a few minutes...
No problem Rafael. It's nice to talk to someone other than myself about using half-plate bookform holders.
I believe these were originally sold in sets: they seem to have exposure numbers enamelled, so that one bookform runs 1-2; next 3-4; next 5-6 etc. I guess by the time Fidelity DDS's came about, the enamelling numerical costs were extraordinary. The book forms have a real quality about them. Heavy, unergonomic, they're still beautiful. I'm just hoping they do lay film flat though.
The basic problem with these holders is that there was no standardization of the attachment details. Even though a set might have been made in the same country at the same time as some other maker's camera, they can't be attached.
In order to confuse those in the U.S., they are most often referred to as Book Form Double Dark Slides.
That's true Ernest: The Thornton Pickard size of half-plate book form holder is at least 10mm too short to fit a Gandolfi, or seen the other way, the Gandolfi is too big for the standard Thornton Pickard half-plate film holder. The standard size of the British half-plate camera era camera is more confusing partly because a lot of the sellers of these vintage relics don't have a clue as to what they were used for, and at times, don't know whether to measure the wooded area; the wooded area plus the slide lip, or the inside of the holder area, or the open exposed black area underneath the removed slide. This is one advantage of procuring a set of book form film holders with a camera, rather than trying to assemble a working half-plate kit from scratch. If there was any feasible demand for making a half-plate reference resource page on LF Forum, this would be a great idea, since the format has proven its feasibility over the past 100 years. That's got a lot more going for it than 35mm has.
My pre-WWII Japanese half-plate back might take standard 5x7 wooden holders with the addition of parallel flanges on the side. These can be made from wood or metal, and attached to a couple of my vintage wood holders. The negative would be 5x7 but the exposed portion would have the half-plate length. Masks could be added to the half-plate format. The back has a felt strip to take care of light on one side, but no groove to receive the holder ridge (which would probably have to be taken off the holders by planing). Am I missing something here? Without a ridge or felt, what keeps light out of the joint between holder and back on the slide side? Should I add felt to the holders where the ridge is now? Anyone tried this before?
My pre-WWII Japanese half-plate back might take standard 5x7 wooden holders with the addition of parallel flanges on the side.
I think so. This makes perfect sense, and looking at my half-plate camera back, it also takes 7x5" DDS types fitting flush against the flanges which you describe. You will have to measure it precisely to work out if it is worth pursuing.
The problem is, there is no pressure plate to keep the 7x5" DDS' in, to protect against a light leak. Your solution, of adding a felt-light-trap would tighten up the flush fitting for the 7x5", although that may make it impossible to fit a half-plate book-form film holder into your half-plate camera. Which seems a shame since that is what it was designed for.
These can be made from wood or metal, and attached to a couple of my vintage wood holders.
Or moulded plastic too. It is likely that some modification would have to be done. The simplest and most crude would be to use rubber felt-lined spring-loaded tool-kit clamp pegs on either top and bottom of the DDS against the back of the camera's wooden frame. It is still awkward since the ground glass on the left-right plane means that the clamp can not fit both left <---> right, and fixing clamp pegs top <---> bottom to hold the DDS against the wooden back, obstructs the removal of the dark slide. Diagonally across the DDS seems to be one alternative. The simplest option is to use a single adjustable clamp with felt contacts (LARGE) across the groundglass frame, sandwiching the DDS in the middle, with the front of the rear standard.
The negative would be 5x7 but the exposed portion would have the half-plate length. masks could be added to the half-plate format. The back has a felt strip to take care of light on one side, but no groove to receive the holder ridge (which would probably have to be taken off the holders by planing). Am I missing something here?
Are you possibly missing......a bookform film type wooden panel holder which sits inside the ridge?
If you plane off holder ridge, you'll have effectively destroyed the half-plate camera in trying to modify it for contracted 5"x61/2" format (the cut off from your 7" length). This will be completely non-standard and highly undesirable as a format ratio, being squat and ugly enough to call an oblong format, rather than rectangular format. Please don't do it - not after the effort you've gone to, in restoring that camera ;(
The other problem which you seem to describe, is that you have no metal side-clip, which needs to be indented for a 7x5" film holder to slot into the back. This offers a little 'grip' by compressing the film holder sideways in the back, thus preventing it from falling out of the camera back when there is no extra pressure applied.
Without a ridge or felt, what keeps light out of the joint between holder and back on the slide side? Should I add felt to the holders where the ridge is now? Anyone tried this before?
I've not tried it, because I had book form holders come with mine.
If you measure the exact ridge gap inserts, this should become clearer.
At the risk of being obtuse and arrogantly imperialist, I'll assert the following:
1). "standard" English half-plate bookform holders are 154mm wide
measured flange to flange. The flange lips are approximately 2mm wide each,
rendering the wall to wall width (i.e. planed off flanges) 150mm. This is the same
distance as the space in a Gandolfi half-plate film back. If your half-plate rear
panel has 150mm width space, then you're in luck, since just about everything still
fits a Gandolfi ;)
2). Thornton Pickard bookform holders are 148mm wide
measured flange to flange. Excluding the flanges, from wall to wall, its width is
approximately 144mm. This falls significantly short of the 150mm required space
to sit flush (i.e. without falling out) of a standard British Gandolfi camera. The
two are easily confused, because there is not a lot of data on tolerances on these
things (Note to myself - remind Mods. to think about creating a book-form/
half-plate page resource in the forum to pool this data).
3). Some English vintage 7x5" wooden Double Dark Slide (DDS) film holders are
149mm wide from flat side to flat side. Most of my batch are 149mm wide. I
suspect that they may have orginally been 150mm wide in manufacture, however
lost a millimetre through wear and tear over the decades. Is this likely? Since
most of the batch I have are consistently 149mm.
1). + 3). fit a standard Gandolfi half-plate camera film back designed for half-plate film, however modification of 3). is required, in order to achieve a light seal.
If you are absolutely sure you have correct tolerances and you have a half-plate camera back, more like 1). rather than 2), then it may be a good idea to insert light traps using felt or rubber seal (which in my view, is a better option since it provides a guaged thickness of 2mm, unlike felt, even if felt is more appealing and more appropriate for the camera and its vintage. Then you may be able to use 3).
You would have to find a way to satisfy yourself that you are measuring the exact indented ridge created by the extension of the protruding wooden flange down to the nearest millimetre, since the tolerances are very variable as Ernest has pointed out.
Hope this helps.
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