Re: Square bellows?

Wayde Allen (allen@boulder.nist.gov)
Thu, 20 Nov 1997 13:07:01 -0700 (MST)

On Thu, 20 Nov 1997, Bob Szabo wrote:

> Ive read a lot of great info about bellows from all the info here my thanks
> to all who have contributed. However my interest is in wetplate cameras and
> would like to make square bellows. Were they folded differently. Is there a
> source for pre 1880 style bellows making? I have not examined a lot of
> originals but understand that not only do they not taper but the corners are
> different too. Am I correct in this? Any help will be appreciated.

I have an article on bellows making that was Xeroxed from an old book.
I'd have to check, but I think it may be from around this point in time.
The information is similar to what you'd get from the View Camera magazine
article or Doug Bardell's web site. It does have a nice, but fairly
tedious method for laying out the fold lines using geometric construction
with a compass.

Fundamentally there is no real difference between a straight walled and
tapered walled bellows. The construction method is basically the same and
the folding is the same. In either case, the valley of one side is the
peak in an adjacent side. The difference is that for a tapered bellows
the rising half of the fold is shorter than the decending half. In a
straight walled bellows both sides have the same dimension, and as a
consequence these are a bit easier to make. I'll try to give you an ASCII
diagram. Hopefully our mail systems won't shift the characters and
screw up their relationships.

Straight Wall Bellows (side cross section):

\ /\ /\
\ / \ / \
\ / \ / \
\/ \/ \ NOTE: four units both down and up

Tapered Wall Bellows (side cross section):

\
\ /\
\ / \ /\
\/ \ / \
\/ \
\ NOTE: four units down for every three up

If you notice the fold "panels" on the straight walled bellows are all
four slashes in length. In the tapered bellows the rising distance from
the bottom of the trough to the top of the next fold is shorter than the
decending distance from the top of the fold to the bottom of the next
trough. In this diagram you go down four slashes and only up three. This
is in fact the reason that it tapers. The fold corners are fundamentally
the same.

- Wayde
(wallen@boulder.nist.gov)