Paper Negative Holders
Does anyone have a super-simple design, something like a film holder, which would allow me to have multiple shots with an odd-sized ultra large format pinhole camera? I've been thinking about a 10" x 16" sized camera, taking half sheets of 16x20 paper: it's 1:1.6 aspect ratio is very close to the Golden Mean or Golden Ratio (as is 12x20,) and I'm rather curious about that right now. But I'd like to be able to make more than one paper negative before retreating to a darkroom (and I don't have a changing bag or tent anywhere near large enough for this beast.)
The difficulty is, mommy wouldn't let me play with tools after the insurance company threatened to cancel her policy and, in all honesty, I couldn't drive a nail if it had power steering. I'm looking for something that could be built with common hand tools. I figure that a pinhole camera isn't all that picky about where the film plane lies; it's pretty much everywhere inside the camera, so the degree of precision of a cut film holder isn't necessary.
i load 8x10 paper into a standard 8x10 film holder. I would see no reason you can't load 11x14 into 11x14 holder
I adapted a pinhole box to 8x10 film holders to give me more exposures in the field. You can find larger holders, although they get mighty expensive.
You might also consider feed and takeup spindles, and just wind the paper after each exposure. Both of those options could be hacked with hand tools.
I shoot mostly large format, so I have 4x5, 5x7 and 8x10 cameras and film holders. I've built 5x7 and 8x10 pinhole cameras (the 5x7 survives, the 8x10 wasn't built well enough to last for more than a couple of months of use,) but 10x16 isn't a standard film size, so there are no film holders I could buy for it. I could go to 7x17, which is a standard size for which cameras, film holders and film are available, but alas, ultra large format film holders are expensive and so is film. If I'm going to go larger than 8x10 I need to keep the cost as low as possible, thus the paper negative path with half-sheets of standard sized photo paper.
Putting paper on a roll-film sort of widget I had thought of and discounted; perhaps I should re-think it. Maybe I'll sacrifice a sheet of 16x20 paper and see how tightly I can roll it without creasing the paper. That'd be rather fun to use, I would think!
I could but I'm wanting something with different proportions than 11x14. Thanks for the suggestion, though!
Originally Posted by williamtheis
If you try for rolls, you could use mailer tubes as your cores. I've got long rolls of paper that come on 3" cores, so I can vouch for that. You'd then just have to set up troughs for trays and do continuous processing. Or you could trough the roll in developer, then cut, then fix.
If you go back to holders, the book 'Primitive Photography' has detailed plans for 10x12 plate holders & you could adapt. It seems to me that you could make holders out of black foamcore board and black cardboard for darkslides. A staple gun & some tape ought to hold it all together. You could probably knock out half a dozen in an afternoon.
I made a rollfilm paper camera a few years back; it got "lost" during a camera swap; it's probably still sitting in the "black hole of Chicago" (inside joke).
It used a 4" wide strip of paper, made by slicing 8"x10" sheets lengthwise and taping them together on the reverse side using painter's masking tape (3/4" wide, doesn't rip the paper when releasing the tape).
The camera used spools made from 4" PVC pipe, so that the bend radius was large enough that there wasn't significant curling issues with the paper. There were flanges on the upper and lower ends of each spool, keeping the paper from falling off the spools; these were made from thin sheet aluminum. The spools were held together, with their flanges, using pieces of threaded rod and lock nuts; which also afforded the opportunity to extend the threaded rods through the top of the camera and attach them to their respective knobs. The bottom ends of the threaded rods sat in oversized nuts, glued to the camera's floor, acting as crude bushings, keeping the spools in position but permitting them to freely turn.
Measuring film advance was a problem. I ended up rolling a strip of thin black paper along with the photo paper, and used large squares of masking tape on the reverse side of the black paper with each frame number clearly printed in large font using a marker pen; a red viewing window in the back of the camera permitted me to view the frame numbers as they rolled by. The number are positioned such that they are centered on where you want the exposed image to be located on each section of the paper strip. For this camera I had two 4"x4' square format images on each 4"x10" section of paper. It's important to ensure that the actual paper doesn't get exposed to light, even through the red filter, which will fog the paper, even though it's filtered. Ask me how I know! ;) Therefore the viewing window looks into a narrow square tunnel whose inside end rubs up against the paper backing strip, ensuring no light leaks around to the front side to fog the photo paper.
For the viewing filter itself I purchased a used 25a deep red filter from my local camera store.
There was also a locking mechanism on each spool's knob, permitting the paper to be tensed tightly once in position; otherwise the paper's stiffness can cause one or both reels to back-roll, giving you a sloppy film plane and/or overlapped images.
I don't have images of this camera, alas. But I had also envisioned a larger version using an 8" wide strip of paper, made from taping 8"x10" sheets together. I didn't pursue this idea, however, because the concept of the falling plate camera struck me, since which I've made three versions. I'll post some on these cameras later.
Try making one out of 8ply mount bd. I am trying this at the moment.
Another approach I've taken to making a camera permitting multiple exposures onto paper is the so-called "Carousel Camera". See this link on F295.
Here's the front view of the camera. It's a two-story camera, with two carousel sections, one above the other. Each story holds four 4x5 negatives. There's an operating knob on the top lid, which is used to rotate the carousel into each of its four positions, permitting a total of eight exposures:
Here's a front view, showing both shutters open. In practice, only one shutter at a time would be used:
The view of the carousel, looking down inside the camera, top lid removed. The two holes are engaged by bolts from the rotating knob, to rotate the carousel:
The two bolts in the lid that are turned by the outer knob. Note the light trap mechanism:
The carousel removed from the camera. Note the curved film planes; you could design a carousel camera for flat film, but the width of the carousel would be bigger. It's made from sheet galvanized steel (inexpensive, easily found in hardware stores) that easily solders together, then roughened up with a wire brush on a drill, then sprayed with metal primer and flat black:
There's a short protrusion on the bottom of the carousel, in the middle, that engages a nut that's been glued to the bottom floor of the camera, acting as a crude bushing permitting the carousel to easily rotate.
Falling Plate Camera
The other configuration of multiple-negative camera I've built is the "Falling Plate" design, of which I've built three versions. Here are some details on one of these models:
Detail of shutter mechanism, shown open. The lower aluminum sleeve that contains the sliding shutter is epoxied to the front of the camera using JB Weld epoxy. The upper brass support for the shutter pull rod is attached using machine screws. The shutter pull knob -- an acorn nut -- is also the top front viewing dot:
Rear view of camera, access lid closed and attached via thumb screws. The black tape on the corners of the rear lid are pieces of gaffer's tape. They've been attached because the sheet of aluminum forming the lid are delaminating from the inner wooden frame of the lid. The entire camera's aluminum skin is JB Welded to the inner wooden space frame, but in the case of the lid it is coming loose in places. In the future, perhaps an inner frame made from square brass tubes (they can be soldered together) instead of wood, and an outer skin made from either sheet brass or galvanized steel (either of which can be soldered, instead of glued) :
Inside view. The camera is constructed around a space frame made from 1/4" thick square hardwood sticks. The thickness of the frame permits mechanisms, like the sliding film changing pin's light trap, to be built into the walls of the camera. Also notice the two parallel sticks in the middle bottom of the floor of the camera; they were intended to hold the tripod nut, but the flexibility of the sheet metal skin caused the whole camera to be very wiggly upon the tripod. Hence the reason why I've since bolted the floor of the camera securely to the beefy wooden tilting support base. Screws securing the camera to the base can be seen in the bottom corners:
Film changing knob. Of course, you can't see the interior light trap mechanism permitting the knob to be slit back and forth; it's really just a 1/8" model plywood plate, sliding inside the 1/4" thickness of the walls of the box (inside a light-tight enclosure with slots for the screws to protrude), with a 6/32 machine screw penetrating from the outer knob to the inner pin:
The ledge upon which the film plates sit; and the front lip (about 1/4" high) which prevents the front plate from prematurely falling off and jamming the mechanism. The distance between the top edge of the film plates and the ceiling of the camera needs to be less than this 1/4" high lip, to that when the camera is jiggled the front film plate won't jump over the lip and jam the works:
Demonstration of a fallen film plate. The camera is tilted forward ~ 45 degrees, then the changing knob is slid sideways. This camera's plates fall so quietly that you really need to listen carefully to hear them fall. Then upright the camera and slightly jiggle it back and forth, to ensure the fallen plate sits securely in the bottom of the camera.
You can also imagine that if the film plate doesn't fall properly, or if the camera is subsequently upended or severely manhandled, the fallen plates can become upset and block the view of the pinhole.
It may not be entirely obvious, but the notches in the top of the plates # 1-8 alternate right, left, right, left, etc. So the changing knob is alternately slid right and then back left to drop subsequent plates. There's space for more than 8 plates, BTW, but I haven't made more:
Some details of the bottom support plate, an addition to this camera's original design. As indicated earlier, the bottom skin of the camera flexes too much to permit a secure mount atop a tripod, especially in the wind, hence the addition of this bulky 3/4" thick plywood double-plate hinging support.
This was originally intended to be used with my homemade tripods, which have a cable loop on the legs permitting the head to be levelled with the horizon, but lacked the ability to tilt the camera. Since most landscape images require the camera to be tilted downward, the mounting plate hinges from the front. A regular brass door hinge is used (see front view of camera, first image in this series.)
The perforated aluminum strips provide for a variable tilt position, using thumb screws.
The additional viewing dots, just markings with ink, were provided when I enlarged the original 5"X8" format to 6"x9.5". These viewing dots are surprisingly accurate in framing one's perspective:
The camera remains very functional, despite several years of severe abuse out in the badlands of New Mexico.
Here's an example, taken atop the Sandstone Overlook in the El Malpais National Monument in western New Mexico. Preflashed grade 2 paper negative: