band across neg/tpgreenspun.com : LUSENET : Large format photography : One Thread
hi folks i've run into something of a wierd problem that i've been unable to diagnose. on some of my negatives/transparencies, i often find a band of slightly different density running along one side. my first guess was that it was a light leak but it's got to be something else. I say that because 1/ the band has a fairly definite edge and 2/ more importantly, it has a lower density i.e., it has received less exposure (whereas a light leak/fogging should add density to this area)- almost like there was a shadow falling on that part of the film. The band appears as a strip on the opposite side to the dark slide opening i.e., near the film loading side of the sheet film holder. Also I only get this problem sometimes, many other pictures turn out fine. I'm unable to figure if it is a particular holder which is defective in some funny way (though i would love to know how) or whether it is some screw up on technique (if in some way i'm casting a shadow onto that part of the film or something). would greatly appreciate any comments/suggestions/help? thanks, dj.
-- Dhananjay (firstname.lastname@example.org), March 04, 1999
Not an answer, just questions, sorry:
How wide is the band? Is the thickness consistent? Only one lens, or all? Different thicknesses for different lenses?
Do you entirely remove the darkslide? If not, that's my best guess.
-- Alan Gibson (Alan.Gibson@technologist.com), March 04, 1999.
I too have noticed a band across some 8x10 negatives. Mine are horizontal, about an inch across the top. I suspect either uneven agitation or insufficient amount of developer (I use trays) because this problem occurs in the skies of landscapes I've shot with a red filter with exposures designated for less than normal development. Maybe I've been trying to process too many negs at once, as many as 7 or 8, emulsion side up.
-- Bruce Schultz (email@example.com), March 04, 1999.
It's possible you are not seating your film all the way down against the stop at the bottom of the holder and the band of less density is really just less exposure from light getting where it wouldn't if it was seated properly.Make sure it is in properly and when you turn it over to make the next exposure, lightly tap it on the palm of your hand to seat it down the other way. It is probably one or two holders. Number the holders and keep accurate records.
-- james (firstname.lastname@example.org), March 05, 1999.
Yes I know this problem, although I see it only rarely. Always occurs across the notched end of the film - do you agree? Don't think any of the previous answers have it nailed. Best as I can tell after careful inspection, the band is lighter than the adjacent area. But this is not because it received less exposure than it should have. Rather the darker area has gotten extra exposure than it should have. I'm pretty certain this is because of fogging. My first thoughts were that it was because the dark slide wasn't pushed fully home at some point, or that the film holder was somehow improperly seated. However, after carefully looking at the seating of a film holder and at the mechanics of the dark slide I'm not satisfied with my explanation.
Hope this adds something and someone out there can solve this darn thing.
-- David Lewis (email@example.com), March 05, 1999.