[pure-silver] Re: [OT] Filmholders, Septums, Total-Disasters

  • From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
  • To: <pure-silver@xxxxxxxxxxxxx>
  • Date: Wed, 23 Nov 2005 14:18:05 -0800


----- Original Message ----- From: "Michael Healy" <emjayhealy@xxxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Wednesday, November 23, 2005 7:04 AM
Subject: [pure-silver] [OT] Filmholders, Septums, Total-Disasters


So I'm trolling for a darkslide replacement the other day, and the house guru of the LF
department says, "Ho jees, not a Riteway, I absolutely refuse to carry those."

Fidelity, Riteway, and Lisco are currently made by the same outfit. The main difference is that the Riteway holder have locking darkslides, i.e., they are unlocked when the holder is placed in the camera.
I have all quite old holders. I've measured those I use with a depth micrometer and a reference place made of a sheet of aluminum thick enough so it won't bow with holes cut in it for the micrometer probe. I have probably fifty 4x5 Riteway holders, made by Graflex. Nearly all are well within tollerance although I've found a couple of bad ones. There is great variation in old wooden holders regardless of make. The best of them are the Kodak holders, also made by Graflex. The worst of the old holders are Lisco. Someone gave me about 25 of these, made in the 1950s, nearly all are out of spec on one or both sides.
I have fewer 8x10 holders, again the best of the bunch are the Kodak holders made by Graflex but I have a few newer ones made by Fidelity deluxe, these are well within spec. I've found the same pattern holds for other sizes. I have a number of 5x7 holders, all old wood ones, the best are the Kodak holders, the same for 2x3 size.
While the ANSI spec for the holders is written for no film film should be put in them for measurement. I chedk the depth at the center and at all four corners to check for warping. Its also a good idea to check the surfaces of the holder with a good straight edge for warping.
Its also a good idea to check the ground glass position. On most sheet film cameras its possible to remove the back or the ground glass panel for checking. Remember to subtract the thickness of the film when measuring. The same technique is used, a plate is fixed as a reference plane and a depth micrometer is used for the measurement.
I've found GG position is very close even in old cameras.

FWIW, here are the standards ANSI standards for holders:

ANSI Standards for film plane placement in sheet film cameras.
Size Location Tolerance + or -

4x5     0.197    0.007

5x7     0.228    0.010

8x10    0.260    0.016

Dimensions in inches.
Film thickness is 0.007 inch  The above does not include
film thickness.
Smaller formats than 4x5 are the same as for 4x5.

Remember that the film plane distance in a _camera_ is the above minus the 0.007" film thickness.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx




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