Fogged edge on 4x5greenspun.com : LUSENET : Large format photography : One Thread
I have a question about edge fogging. I've put an image of the particular kind of fogging I got on line at:
http://www.uwgb.edu/galta/fog/fogged_edge.htm (underline between "fogged" and "edge".)
The fogging shows minute striations and occurs on the end of the film which is under the flap. It occured with a new holder. It doesn't seem as if it is a matter of the tape leaking light. In fact, examing the holder itself, it would seem to me that light leakage of that kind would be difficult because of the light traps built into the flap itself. The holder is a Fidelity elite, used only twice before this sheet of film. I recall that when I used to fumble around with loading 120 film into reels for developing that sometimes I'd get "half-moon" marks that fogged the film and resulted from mechanical creasing of the film. I did fumble around a bit loading this particular set of holders (new film Ilford Delta 100 seemed a little thinner than the Plus-X I was used to and I had a little trouble finding the holder's grooves the first time around). Can there be mechanical sources of fogging as well as light leaks? Any guesses as the source of this kind of fogging?
Fortunately, I work digitally after I develop the film, so I was able to clone over the damage on the image.
-- Tony Galt (firstname.lastname@example.org), February 24, 2002
I had a simlar problem years ago with Toyo holders but it turned out the problem was a defective batch of film. I realized this since I was using two different kinds of film in the same holders with the same loading and unloading technique. So I would recommend processing a sheet straight from the box without loading or exposing it to see whether the film is fogged out of the box.
-- Jeffrey Scott (email@example.com), February 24, 2002.
Other sheets from the same box of film do not show this fogging, so I don't think it is a defective batch.
-- Tony Galt (firstname.lastname@example.org), February 24, 2002.
"....occurs on the end of the film which is under the flap." - The film shouldn't be under the flap of a double darkslide. The film should rest in the holder just short of where the flap folds down. If you trap the film under the flap then the holder won't shut properly, and yes, it will leak light in that condition.
Make sure you push the film fully up into the holder before closing the flap.
-- Pete Andrews (email@example.com), February 25, 2002.
I don't know how you figure that. With the film slid all the way into the holder, the flap covers about 1/8 " of the film yielding the clear border at that end.
-- Tony Galt (firstname.lastname@example.org), February 25, 2002.
Tony: I agree with the last post. On the film holders I use (which is lots of different ones) the film when fully inserted is not under the flap. You can shake them all back and forth and hear the film to check and see if they're loaded. Couldn't do that with the film stuck under the flap. The light trap built into the flap won't work if film is in that space.
-- Kevin Crisp (KRCrisp@aol.com), February 26, 2002.
There must be two designs for holders then. On both the older Riteways I have, and the newer Fidelity Elite, when the film is fully inserted the notched edge is under the flap (there is clearance) and the flap closes so that it is flush with the rest of the holder frame and is, presumably, light tight. I still don't understand where my fogging came from. Maybe it was a fluke and won't occur again.
-- Tony Galt (email@example.com), February 26, 2002.