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Hi Bob,
The sheen on this material
is sort of like what you would see on a typical windbreaker , parka
, or coat , only a little duller.. I was hoping to just get it dead flat
with out a lot of hassle.. I think I just may spray it lightly with some sort of
flat black urethane product and call it a day.. I personally think
it is not that critical as all the folds will act as baffles.
On my Toyo bellows the sheen is much greater on the original bellows, but I also
have a light problem.. ... The replacement is flat black..I guess I will paint
it only after some tests to see if it is even
necessary...
----- Original Message -----
Sent: Friday, November 29, 2002 7:49
AM
Subject: Re: [Cameramakers] bellows liner
sheen
Regarding the suggestion below, maybe the textured surface
could be fine sandpaper sprayed with some non-stick coating or else PE sheet
with the impression of sandpaper to roughen up the surface. Perhaps a
coat of wax will doe the job of separation agent..
Another hard- to-
stick- to surface is polypropylene. It is sometimes used as sewer pipe
(we get it in gray color). If you nicely sand the surface it will
become quite matt, eventually. Try rolling the coated cloth onto
that.
Please make a little trial piece before taking on the whole
bellows-sized piece.
Incidentally, one reason I tilt toward the
silicone is its stability and consequent long lifetime. It remains
elastic instead of melting to a paste (like some polyurethane), turning
brittle like rubber, bleeding plastisizer like PVC, and so on.
Bob
At 11:54 29.11.02 +0100, you wrote:
I am not sure this is possible
but you can coat the stuff with thin layer of silicone of the sort used for
sealing bathtubs, aquariums and....... You can thin it with a
considerable amount of mineral spirits (it takes a lot if you want to brush
the result). Add enough carbon black (I had success with about 10 %
printers ink) to make thin layers quite dense. This will fill the
"pores" and also increase the resistance to some kinds of damage (and could
be used to bond the fabric to the next layer). If you now uniformly
press this mess onto a suitable sheet of polyethylene or other non-stick
material which has the surface appearance you desire, you will copy the
surface in the silicone! The real problem is finding a non-stick layer
of something having the correct surface. Much polyethylene is too
shiny and the end result would be worse than you now have! Still, if
you can locate the correct stuff, I am quite sure the process will
work.
There is a second point of view; I cannot think of any
reason to worry about the shiny appearance! Yes, it reflects in a
specular way, but if the source makes a broad beam, the specular reflection
of that beam will be no less well spread out. The main source of light
is what bounces back from the film or film holder. Certainly the film
scatters light well and probably the black film holder is not too bad
either. It can easily be that a flat black surface reflects
considerably more total light than your shiny
one.
It is hard to produce truly "dead"
black. Light traps offer the best hope and flocking is one way to
reach this goal. I have seen a bellows with partially flocked inner
surface. If you are good, maybe you can fl�ocking to adhere to the
silicone (but hurry, before a skin develops!)
Bob
At
08:39 26.11.02 -0500, you wrote:
Hi,
I am in the
process of building a 24x24 camera bellows and I found this
wonderful material called "Emphatex." . It is a 2 ply
coated breathable nylon material used to make sports gear......It is
extremely thin , light and subtle and is almost 100 percent light tight by
itself, however it does pass a very little light.. ... With two
layers I am sure it will be completely opaque.. The question or
concern I have is that the material has a slight or dull
sheen to it and I was wondering how critical do you think it is to
have a liner in the bellows that is dead flat
black?
If it is critical does
anyone have any suggestions to dull the sheen..
Also is there any
recommendations for liners that are dead flat black..
Thanks,
John
Cremati
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