Here's a gif file showing a detail of the pattern I used to design the square bellows. (Note the pattern is different for a conical bellows.)
layout pattern detail
Dimension "A" is the width of the fold. Dimension "B" is the length of the inside opening of the bellows and dimension "C" is "B" - 1/8". Stiffeners are illustrated in gray tone. You need to have a 1/8" gap between all stiffeners in order for the bellows to fold properly.
In this bellows the dimensions are:
A = 1.00" (= width of corner fold)
B = 9.25" (= inside dimension)
C = 9.125" (= rectangular stiffener length...width is A - 1/8"...trapezoidal stiffeners formed by adding a 45-degree right triangle to both ends of the rectangular stiffeners.)
exterior dimension = B + 2A =11.25"
maximum extension ~ 24"
minimum extension ~ 1.75"
There are 15 pairs of stiffeners (30 total inches) for each of the 4 sides. This gives a comfortable extension of about 24" and the bellows compresses to less than 2" minimum. I planned the extension based on a dimension to get a life-sized, 1:1 magnification with a normal lens (~10.75") for the full plate format (6.5" x 8.5"). Thus, I wanted at least 21.5" extension and figured I'd need about 30% more length to achieve the proper extension. So 21.5" x 1.3 = 27.95" and so I rounded it upward to an even 30" hence the fifteen 1" pairs of stiffeners per panel. There is also an extra 3" of material at top and bottom to allow for attaching the bellows to a bellows frame which is then screwed onto the camera front and rear boxes.
For this camera (under construction) the inside bellows opening was designed to allow the use of an 8.5" square #6 synched Packard Shutter mounted internally behind a large 8" lensboard. This shutter has a opening diameter of 5" and will allow the use of very large barrel portrait lenses (e.g., 18" f/4 Verito, 16" f/3.8 Vitax, etc.) on the camera. That's the reason a 9.25" inside square bellows was needed. It had to clear an 8.5" glass plate (horizontally and vertically) at the rear of the camera, and allow for the 8.5" square Packard Shutter and air fittings at the front.
More to come...
I've seen other bellows construction plans that look like a mess compared to yours. It looks like the folds and corners would like to get into place, compared wit Dough Bardell's method. I have already used the latter and experienced that it is almost impossible to get a (conical) bellows that is correct to the millimeter.
Using individual stiffeners seems to be the key to get perfect folds. The trick with the punched holes and cutting out the grooves (see DB's website) will never result in all stiffeners being of equal height (i.e. 1-3-5-7-9... and 2-4-6-8-...) and perfectly symetrical.
I don't know if your method (i.e. let the stiffeners run up into the corners) would work for a conical bellows. I'll give it a try next week. I've got a whole roll of brown wrapping paper to test.
I've finished a bellows as well a few days ago, for a 4x5" enlarger I'm building, and which is almost finished. I also found it very exciting and actually easy to fold it and see it come to life progressively!
I'm rather astounded by the price of your bellows ($60). Mine have costed 4 euros. That was the price of 45x100 cm of black and thick adhesive, the one you find in the wallpaper section of shops. The rest was just some cardboard and a matte black aerosol painting for the inside.
The size of the bellows : 16x13cm, and it extends from 6 to 35 cm.
I've followed an old article I've found on the web :
Skander, any chance of more information about building your 4 x 5 enlarger? Is this a build from square one or have you adapted an old camera?
I have always felt the problem with moving up to 4 x 5 was having to buy an enlarger as well as the camera. Somehow the idea of building a 4 x 5 enlarger seems less daunting than building the camera itself.
(Newcastle upon Tyne, England)
Actually, I've found an old Durst 805 6x9 enlarger. It lacked the condensers,
bulbs ... only the skeleton remained, with nice and sturdy column and baseboard.
The head was large enough to allow a hole to be made for a 4x5 neg carrier,
which I did.
It had no bellows but a large cylinder, at the end of which you put the lens,
and this cylinder screws into the head. Screwing or unscrewing moves the lens
nearer or further from the film plane, but it was not able to move far enough
for long focal lenses (135 or 150mm) to be used. I then made a bellows to be
placed between the cylinder and the head.
The main issue was, as always, the light source. As I don't have any condenser
nor the ability to build one, I first wanted to buy a 4x5 head, but it proved
rare and expensive, so I planned to put a garden halogen lamp over the head,
and diffuse the light with some ground glass. I placed aluminium sheet on the
inside sides of the head to reflect the light, but though there was a big fall-off
in the corners. I then changed the light source : I drilled 5 holes in a small
board, in which I placed five 60 W krypton bulbs. Four are placed in the corners,
the fifth in the center. Between the neg and these bulbs, I placed what I have
found to be the best diffuser screen, both for the homogeneity of the diffusion
and the little quantity of light it absorbs : a simple sheet of tracing paper.
The last problem was that it was far too hot with 300 W, and some plastic parts were melting. Hence
I placed two
computer fans : one vertical behind the neg carrier and the tracing paper which
blows air inside the head, and one horizontal over the bulbs, which pumps the
air from the head to the outside. It perfectly works : the bulbs can stay on as
long as I want.
It's nearly over : I thought it was but it remains to seal all the light leaks,
and to print the first tests! So far, I've only one concern : the fans induce
some vibrations, though they were fastened with flexible materials. It's hardly
noticeable, but I fear it might affect the sharpness of the print. I'll have to try, probably in a few days, to know.
I probably will post some photos and comment the results in a thread if all goes well...
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Thanks. Actually, when I tore apart the old conical Burke and James bellows I had, I saw the trapezoidal stiffeners ran into the corners. The difference was that an entire side panel would have pairs of trapezoids and the other two sides didn't extend into the corners. (The stiffeners on those two sides were also trapezoidal rather than rectangular but with angles more like 75+15+90 for the right triangle.) I could see why one wouldn't want the stiffeners to extend all the way into the corners for all four panels because the thickness of the corner folds would almost double in thickness as a result. However, I couldn't see any reason not to alternate the trapezoidal pairs with the rectangular pairs other than it took a bit longer to lay down the alternating pattern. I thought the alternation might add some additional stability for both the vertical and horizontal panels and also make the corners more stable. It may have added to the ease at which the folding occurred. I don't know this for sure since I've never made another bellows previous to this one where I could compare methods. I expected the folding to be the most difficult part based on what I've read, but I was surprised at what turned out to be the easiest part of the construction.
Originally Posted by argus
Well, let's double-check keeping in mind this bellows required about 2.5 times the surface area of yours:
Originally Posted by skander
~36" x 48" rubberized darkroom cloth @ ~$25
~36" x 48" liner material @ ~$8
1 can automotive headliner spray ~ $8
1 can automotive trim adhesive spray @ ~ $13 (I was surprised at this cost)
~ 500ml contact cement @ ~ $6 (IIRC...didn't use much of the can though)
4 sheets posterboard for stiffeners @ ~ $5
2 sheets black foamcore for the form @ ~$11 (didn't really need this but it was helpful.
That brings the cost to about $76 not counting various sundries like the fabric pencil, and masking tape and paper towels used to keep the glue off surfaces. IIRC, the last bellows I purchased was around $380 plus overseas shipping costs for one about 19" square x 52" long for an 11x14 camera. So, the material cost for a handbuilt one that size would quadruple, but still save me around $100. Not a great savings considering the time involved, but I'm enjoying the fact I made the bellows myself. Once I get the camera built and start pouring my own glass plates, I'll be as close to making a photograph from scratch as I can get without becoming a chemist. (And so much for the digital vs film debate as far as I'm concerned.)
For the next bellows, I think I'll use headliner spray exclusively since it seemed to bond better, was less expensive than the other spray, and easier to apply than the contact cement. The contact cement also soaked into the liner fabric which was more porous and required several coats and a longer time to cure.
So, you're basically saying that, once you've done one or two, you could (even accounting for cost of materials) make something like $40/hr making these things? Tell me more!!
Originally Posted by smieglitz
Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.
I bet the market isn't big enough to make a living out of it but it sure would pay for some film and chemicals.
Originally Posted by Donald Qualls
Originally Posted by Donald Qualls
I wouldn't quit my day job.
This took a lot of space and was pretty messy with some not-so-good-for-you adhesive fumes in the air. It might make a nice cottage industry if you had enough space and ventilation, assuming the demand was there.
And, although this one came out very nice, it isn't perfect and as good as it looks, it looks homemade. The bellows I ordered from Camera Bellows, Ltd. in England is absolutely perfect. It's like comparing anything handmade and crafted (woven rugs, ceramics, etc.) to something machine-made.
As Frank Zappa once crooned: "Is that a real poncho or is that a Sears poncho?"