Background and Bellows Design Considerations
Several years ago I decided to take up ultra large-format photography (ULF) as I have slowly moved towards practicing alternative process printing methods exclusively. These processes, Van Dyke Brownprinting, Cyanotype, and Gum Bichromate in my case, require large negatives for contact printing since the emulsions employed are so slow. Since I have always enjoyed the 11"x14" print format I decided to migrate to that camera format.
I quickly realized that only a few modern field cameras could handle the large portrait lenses I wished to use on the camera so I decided to build camera specifically to take into the field, but geared to portraiture and figurative work. I wanted to employ these barrel lenses but also wished to have some sort of working shutter. I settled on a large synched #6 Packard Shutter that had an opening diameter of 5" to accommodate the large glass of the lenses. This particular shutter is 8.5" square and this has many ramifications for the design of the camera: large lensboards and wide, sturdy front standards are needed to mount the large lenses and shutter. And, as a result, any bellows for the camera must surround the large shutter if it is to be mounted internally within the camera.
I also wanted to use these long focal length portrait lenses on nearby subjects so a large bellows extension was called for. I eventually ordered a custom bellows from Camera Bellows, Ltd. for the 11x14 camera and was very pleased with the product although it cost several hundred dollars.
Midway through the 11x14 camera building project I was struck with the desire to try wetplate collodion photography. Wetplate requires a special back and plate holder for the camera. At first I planned on adapting one of my other cameras with a special wetplate back, but decided to build a camera from scratch instead, again wishing it to accommodate the large portrait lenses and Packard Shutter. This time I decided to build the entire camera including the bellows. The reasons for this were a potential cost savings compared to ordering a custom product, but, more significantly, I wanted to see if I could completely design and craft the entire camera myself. Having enjoyed the hand-crafted aspect of the alternative printing processes and now anticipating pouring my own glass plates, I believe the crafting of the camera will add to the inherent satisfaction I'll derive from this photographic process.
In terms of design considerations it became apparent that I would need a bellows that could circumscribe the 8.5" square shutter and also allow for the traditional full-plate dimension of 6.5" x 8.5" at the rear of the camera. I'd need a little flex room to clear the plate, shutter and camera box, so I decided to construct a square bellows with an inside dimension of 9.25" and 11.25" for the outer perimeter. This would give me pleat dimension of 1" and while increasing the size of the camera a bit, I thought that best since I"m only a novice woodworker and wanted to simplify the camera construction if I could.
I also wanted a bellows extension that would allow a life-sized magnification (1:1) with the normal focal length (~10.75") for the full-plate format. This gave a target extension of approximately 22" for the bellows. Taking into account the fact that the folds of the bellows reduce the overall length by a factor of about 1.3x, I targeted 30 (22" x 1.3 = 28.6") as convenient number of 1" fold panels/pleats to be incorporated in the bellows.
The square bellows design would also simplify the camera box construction and easily allow for making a reversible back to do both horizontal and vertical photographs.
So, there's the logic in why I needed a square bellows of the size I constructed. Now all I had to do was figure out how to make the bellows.
The references I had seen to making camera bellows were all helpful to some degree, but all modern information concerned constructing a tapering bellows. Such a bellows allows for a larger compression (i.e., minimum extension), but that was not one of my primary design parameters. (And the finished bellows I made compresses to under 2" anyways.) For others making more traditional landscape field cameras where weight and size are more of a concern, that sort of bellows may be more desirable.
If so, you may wish to check Doug Bardell's web page as well as James Vail's camera making page. Both sources added insight into the bellows making process. (I also had downloaded a somewhat cryptic pdf file of an old Deardorff bellows construction page, but I'm not sure that information is still available online.) The July/August 1996 issue of View Camera magazine also had a very helpful article on constructing a bellows written by Mike Robinson. The final source I consulted was a reprint of Paul Hasluck's 1901 "Photographic Cameras and Accessories: Comprising How to Make Cameras, Dark Slides, Shutters, and Stands" (ISBN 1-55918-252-0). The latter source only has a couple pages devoted to bellows making, but it does cover making square as well as tapering bellows and it has drawings and plans for constructing a variety of cameras and other equipment. Following construction of my first bellows, I was subsequently referred to another online instructional source for constructing a square bellows at Daniel Rhoades' website . His directions and design are different than mine and so present an opportunity to compare notes. For a good general list of cameramakers online see Jon Grepstad's cameramakers links page.
In effect, I was pretty much on my own when it came to making a square bellows although I did find the View Camera article helpful in envisioning the bellows pattern. Taking a little bit of direction from each of the references above, I embarked on the bellows construction.
General Directions for Constructing a Square Bellows
Major materials include the outer lightproof bellows fabric, paper stiffeners, and the inner black lining material. (Some other online sources list the liner as optional.) The stiffeners are glued to the inside surface of the bellows material and become sandwiched between that outer layer and the inner liner material when the latter is glued in place. These stiffeners should be cut 1/8" smaller than the width of the bellows pleats in order to allow the bellows to fold compactly. In my design, there are two stiffener shapes employed: rectangles and trapezoids.
In many ways the construction of a square bellows is simpler than that of a tapering bellows. It is much easier to draw the pattern (Figure 1) of the former and since the bellows is fairly uniform throughout, dimensioning and cutting the pleat stiffeners was easier. Tapered bellows are generally constructed inside-out and then inverted by pulling the small end through the larger end (much like pulling an inverted shirtsleeve back into place when folding the laundry). I couldn't see how this could be done with a square bellows without damaging the integrity of the stiffeners, so I forewent that procedure and constructed my square bellows without inverting it. (In retrospect, I don't see why this procedure is actually recommended when constructing a tapering bellows. I imagine gluing the stiffeners and liner would be just as easy with the tapering pattern as with the square design when following my procedure.) A square form constructed from foamcore (figure ) and just slightly smaller (-1/4" on each side) helped in gluing the bellows seam and in the initial folding of the bellows. While the bellows can be constructed without this form, I found it helpful to use.
Once the extension of the bellows has been determined and the desired dimension of the inside square opening and the width of the pleats is known (either by measurement of the old bellows or by a new design), the material for the bellows and liner can be cut. The pleat width is usually 1" or wider for 8"x10" or larger formats, and generally around 5/8" wide for smaller cameras. Plan on leaving a few extra inches of material on the ends for attaching the completed bellows to a bellows frame or directly to the camera.
You will also need to plan for an overlap of material for the bellows seam which is located on the underside. I suggest having a seam width equal to the width of one pleat. In constructing my bellows I used enough material for 5 full widths of the bellows to simplify the cutting of the diagonal seam edges (Figure 1). Cutting the seam diagonally allows the bellows to compress further. If the seam were cut straight, the cumulative thickness of the overlapping seam material impedes the compression of the bellows. Having a diagonal seam minimizes the overlap and thickness problem.
Figure 1. General bellows layout. Note the diagonal seam line.
Bellows Layout and Construction
Important dimensions to consider in constructing the square bellows (Figure 2):
- Inner opening width : A
- Pleat width : B
- Outer dimension of bellows : C = A + 2B
- Length of rectangular stiffener: D = A - 1/8"
- Width of rectangular and trapezoidal stiffeners: E = B - 1/8"
- Minor length of trapezoidal stiffener: F = D = A - 1/8"
- Major length of trapezoidal stiffener (see note below on cutting this shape): G = C - 1/8"
- Overall width of material used : 5A +3B + 4B
- Overall length of material used: (extension desired x 1.3 x B) + 4B
Figure 2. Bellows stiffeners layout pattern detail. Note that a 1/8" gap exists between each stiffener edge to facilitate folding of the bellows.
- In a well ventilated space, find a large uncluttered horizontal surface to layout the bellows design on the material.
- Cut the material used for the bellows to size and secure it to the surface using masking tape. (I used a rubberized nylon fabric for this layer. The outer surface has a nice sheen to it which I felt complimented the look of the finished project.) Be sure to lay the bellows material out as flat as possible and have the inner (rubberized) surface up. I would also suggest masking off an area around the perimeter of the material with paper toweling to avoid getting adhesives on the surface upon which the bellows material is laid.
- At a distance from one edge of the material equal to a distance of 2B, begin drawing the first bellows panel and corner design (the white lines evident between stiffeners in Figure 2) on the fabric using a sewing fabric pencil. A large carpenter's square or steel yardstick/meterstick will facilitate the drawing process.
- Repeat drawing the panel design for the remaining sides and corners. When finished you should have 5 panels of inner opening width A separated by 3 squares of width pleat B (figure 2).
- Draw a zig-zag pattern of 45-degree diagonal lines in each corner square. The diagonals should be mirror images of one another on opposite sides of the panels (again consult figure 2).
- At this point you may wish to draw a straight line 1/16" from one edge of each panel. This line will aid in laying out the stiffeners later on. An alternative is to draw a straight line the entire length of each panel from the panel midpoint and make a similar mark on the stiffener material sheet at its midpoint before the individual stiffeners are cut to size.
- Come in about 1/5th of the width of the leftmost panel and make a mark at the top of the panel (Figure 1). Make another mark the same distance away from the rightmost side of the same panel at the bottom edge. Draw a straight line between these two points and extend it beyond the fabric onto the horizontal supporting surface. This will become part of the bellows seam. (The reason for extending the line off the material will become obvious as the bellows seam is cut just prior to final assembly.)
- Repeat this procedure on the rightmost panel but allow for an overlap of the two edge panel sections equal to the pleat width B when the seam lines are cut. (For example, with a bellows of 1" pleat width and inner opening equal to 10" the seam line on the leftmost panel would start 2" in from the left top and run diagonally to a point 2" in from the right bottom of that panel. On the opposite side panel, the beginning of the diagonal seam line would start at 3" from the left top panel edge and extend to a point 1" in from the bottom right of that panel. When the seam lines are cut and the bellows assembled, this will produce a diagonal seam overlap of 1" on the bottom panel of the completed bellows. Reference Figure 1 again.)
- Cut the stiffeners to size. (I used a drafting 45-degree right triangle taped to the square guides of a rotary paper trimmer to facilitate the cutting of the trapezoidal stiffeners. Rectangles of the proper width were aligned against the triangle so the blade intercepted the stiffener at the corner thus cutting a 45-degree angle on the end. The procedure was then repeated on the opposite end of the stiffener to form the trapezopidal shape of correct length. I will upload a photograph of the setup soon.) You will need to cut 4 panels' worth of stiffeners. For example, if you decide to construct a bellows with 30 pleats per panel, you would need 120 stiffeners. I would suggest cutting a few extras in case you ruin a couple during gluing of the stiffeners to the bellows material. For the set of stiffeners designated for the seam layer, I lined up the stiffeners ahead of time and cut them, first for the rightmost panel and then for the leftmost one, so that the stiffener material would not be present in the seam overlap. This essentially cut out a piece of material from the center of each individual stiffener equal to the pleat width. If this is not done and the stiffeners are left intact, then they must be applied to one panel and left partially uncemented until the seam is glued at the final construction step. (I thought the double thickness of the material forming the seam would compensate for any compromising of integrity of the stiffeners in that seamed panel so I went ahead and cut those stiffeners. In retrospect, I believe this made the final gluing of the seam and the folding of the bellows much easier and did not impact the integrity of the bellows to any practical degree.)
- Apply the spray adhesive to the bellows material and the reverse side of the stiffeners. You may wish to only do a small section or single panel at one time. (If you won't be employing liner material, you will need to avoid getting adhesive in the 1/8" fold gap between stiffeners. If that is your plan, you should probably use contact cement and carefully apply it to both surfaces using a brush.) You should be able to view the drawn pattern through the adhesive. (I used a headliner spray adhesive and found this preferable to contact cement largely because of ease of application, bond strength, and reduced curing time. The contact cement also soaked into the porous liner fabric and required several coats when I experimented with it. I also believe the spray adhesive didn't produce the same volume of noxious fumes as the contact cement.)
- Coming in 1/16" from the top of each drawn pleat, affix the stiffeners to the bellows material lining up the corners of the stiffeners with the guide mark drawn previously. This should result in the rectangular stiffeners being 1/16" in from the corner folds and edges of the pleats. Likewise, the trapezoidal stiffeners will also be 1/16" in from the pleat and corner fold edges. Be sure to press the stiffeners firmly and accurately into place. If done properly, this produces a gap of 1/8" between each stiffener and allows the bellows to fold easily along this unreinforced material. Note how pairs of rectangular stiffeners alternate with pairs of trapezoidal stiffeners within and between the panels (Figure 1). I believe this pattern minimized the thickness of the corners while at the same time helped reinforce the folds in both the horizontal and vertical panels. (Other bellows designs usually have the trapezoidal stiffeners all on the top and bottom panels with no stiffeners from the side panels extending into the corners. My design may not have made any difference, but I believe it helped make the bellows easier to fold. I'll have to compare this technique with the more standard one on a different bellows project in the future.)
- At this point you may wish to let the adhesive cure overnight.
- Apply adhesive to the combined bellows fabric and stiffener layer.
- Carefully lay the liner material over the bellows and stiffener layer taking care to avoid wrinkling the fabric as it is applied. (You will probably find this task easier if you enlist the aid of another person or two.)
- Using the guide marks previously extended onto the horizontal surface surround the bellows material, redraw the seam diagonals on the liner fabric.
- Using a sharp pair of scissors, cut the two diagonals which will form the seam.
- Carefully apply adhesive to the surfaces of the seam overlap which will be joined. The way I did this was to first fold the rightmost panel back towards the center of the bellows. I placed a layer of paper toweling between this panel and the underlying layer along the fabric diagonal. Using masking tape, I then masked off the material leaving just the width of the seam overlap to receive the adhesive. I also used masking tape in a similar fashion at the seam overlap for the leftmost panel. Note that one panel receives adhesive on its outer surface and the other gets the glue on the inside surface assuring a strong bond when the seam is overlapped.
- Carefully overlap the seam and press it together firmly. At this point, I took a piece of masonite (any flat board would do) and laid it over the flattened bellows. I used a number of books as weights on top of the masonite panel to press the bellows seam together. Let the adhesive cure for another hour or so before removing the weight.
- After removing the weight, when you pick up the bellows you will find it is now more or less in the shape of a tube. (Previously I had constructed a form out of foamcore just slightly smaller than the intended bellows and I slipped the bellows tube over the form leaving about 3"-4" off the form. The form is totally optional but may aid in the folding process. I really don't think you need it in order to finish the bellows, however I had read somewhere that it was useful so I constructed one ahead of time.) The bellows should form a sort of orthorhombic shape as you straighten the panels and lift the tube. At this point grasp the first and second pleat on one panel and form the first fold in the bellows. Go to the opposite panel and pinch the first two pleats together there to form a similar fold.
- Next turn the bellows 90-degrees and fold the first pair of pleats on that panel in the opposite direction of the two you did previously. (In other words, if the first fold on the top and bottom surface formed a crest outward, the first fold on the side panels should form a trough inward.) You may have to "pop" the corner fold into place since it will want to go in the opposite direction. Turn the bellows and repeat this fold on the opposite side.
- Return to the first panel and make the next fold. Repeat the folding procedure above for opposite and then adjacent sides and the bellows will soon begin to take on the accordion appearance. I found it helpful to use small clamps to secure the initial and later folds in place until the entire bellows was folded. I used large binder clips and some small plastic woodworking "A-clamps" to secure the folds as I progressed. (Take care not to puncture the surface of the bellows using such clamps.) After the first couple folds, the procedure became second nature and I was able to complete folding the 30" bellows in about two minutes.
- Compress the folded bellows and then place it under weight to set the folds overnight.
- Using the extra material at each end, fasten the bellows to your bellows frame and/or camera.
The Completed Bellows
Figure 3. The completed square bellows.
Figure 4. The completed bellows next to a 35mm camera for scale. The black foamcore construction form is also shown.
Suggested Material List
- Outer bellows materials: I used "Darkroom Cloth" sold by Porter"s Camera Store - this is a thin rubberized nylon material. Porter"s sells two types of blackout cloth. I used the thinner, more expensive material.
- Inner Liner Material: I used a 150 denier black matte polyester "Supersuede" from Outdoor Wilderness Fabrics. This was a special order. Similar material can probably be found at a local fabric store.
- Stiffeners: Cut from black posterboard. Manila folder material or even a paper such as 300# watercolor paper could also probably be used.
- Adhesives: I used a variety of adhesives on my initial bellows, largely because I ran out of my preferred adhesive and had some of the other cements purchased for the project. I preferred to use a spray product named "Heads Up Quick-Fix Headliner Adhesive" which I found at a local automotive supply and which is manufactured by Heads Up Industries in Fort Lauderdale, Florida (telephone 954-472-3300). I also used DAP Contact Cement for the seam but would use the headliner spray adhesive for this purpose next time.
- 1" wide masking tape
- paper toweling
- fabric pencil for drawing the bellows pattern on the fabric
- sewing scissors
- large carpenters' square, t-square, yardstick or meterstick for layout
- 12 small A-clamps, large paper binder clips, or alligator clothespins
- rotary paper trimmer and drafting 45-degree right triangle (both optional)