What casued the 'insect' spot on this negative?

I'm new to large format camera, have a Zone VI 4x5 and am trying to get used to the movements and sheet film handling. I shot and processed this negative the other day. The film is Arista.EDU 100 processed in R09 1+100 in a Jobo 2520 tank using inversions rather than continuous agitation on a roller. There's this spot(?) on the left side (as you look at it) of the negative. Static discharge? Is there a way to tell if it was before exposure (in loading the holder) or after (loading the tank)?

It looks like static electricity to me. I don't know how to tell what caused it.

+1 for static electricity. If you're working in cold weather, load film slowly into the holders and remove/replace dark slides slowly as well.

Vincent and AJG, thanks for the replies. I've only noticed this on 3 sheets and just in the last week during the cold spell we've had. I'm using plastic holders, are these more prone to this than the older wooden holders? Also, there is a very thin straight line on the right side of the negative. I've seen this in several sheets from several (all the same type) holders. It's straight, sharp, and parallel to the edge of the sheet, so I'm thinking it's not a light leak. Any ideas?

From the print-through number system, you're using some new-fangled type of DDS holder?

 

I've only ever used plain-vanilla Toyo holders, or Fidelities if I have to. I have never had a single instance of static discharge on the negative. Nor any strange lines on the film (which should be outside of the viewing/focussing screen area anyway).

 

Maybe it's worth looking at the clothing you're wearing, or what your changing bag is made of, how you store your darkslides etc. Nylon or other synthetics will encourage static build up.

 

WRT wood. I'm of the opinion that it can't be made with the same accuracy as plastic, nor kept as clean. And anyway, the holder material may have nothing to do with the static discharge. It may be coming from your fingers as you remove the film from its black plastic bag.

 

A quick 'huff' of humid breath can dissipate static charge from a plastic bag or suchlike.

Edited February 3, 2019 by rodeo_joe|1

From the print-through number system, you're using some new-fangled type of DDS holder?

 

I've only ever used plain-vanilla Toyo holders, or Fidelities if I have to. I have never had a single instance of static discharge on the negative. Nor any strange lines on the film (which should be outside of the viewing/focussing screen area anyway).

 

Maybe it's worth looking at the clothing you're wearing, or what your changing bag is made of, how you store your darkslides etc. Nylon or other synthetics will encourage static build up.

 

WRT wood. I'm of the opinion that it can't be made with the same accuracy as plastic, nor kept as clean. And anyway, the holder material may have nothing to do with the static discharge. It may be coming from your fingers as you remove the film from its black plastic bag.

 

A quick 'huff' of humid breath can dissipate static charge from a plastic bag or suchlike.

 

The holders are Riteway plastic holders that I received with the camera. I particularly like the numbers in the holders; handy for associating the exposure details of each sheet after they come out of the developer when still experimenting/learning. I'll look at the materials of the camera bag. I don't use a changing bag, just do the loading/unloading in the darkroom.

WRT the white line on the right--it is possible that one sheet of film was touching another during developing in your JOBO tank. As far as keeping track of which sheet got which exposure, etc., I numbered all of my holders and dark slides and shoot them in numerical sequence. I also use a JOBO 2500 tank with 2 reels for a total of 12 sheets at a time, and am careful to load them in order so that I know which sheet it was and also which holder it was in the event of problems with light leaks, scratching, etc. For cleaning holders, I have found that a cordless vacuum cleaner works the best to prevent dust spots. Compressed air can blow dirt into light traps only to have it reappear when dark slides are inserted or retracted.

A pair of very small triangular and circular files can be used in various combinations on the flaps on each side of film holders to make notches of different combinations to mark on the edge of each sheet of film to identify which sheet was exposed on which side of each holder. Similar to the numbering friskit Linhof used on their sheet film and their glass plate/sheet film holders.

+1 on static discharge. However I've never had a problem with plastic holders. It usually occurs when you separate sheets of raw film from the stack before loading. This is consistent with the fact it appears near the edge with the notches. It is extended because that action involves peeling the layers apart. Plastic holders still have metal clips and base plates, which dissipate static. Static is generated when you rub or separate two dielectrics, e.g., sheets of film.

+1 on static discharge. However I've never had a problem with plastic holders. It usually occurs when you separate sheets of raw film from the stack before loading. This is consistent with the fact it appears near the edge with the notches. It is extended because that action involves peeling the layers apart. Plastic holders still have metal clips and base plates, which dissipate static. Static is generated when you rub or separate two dielectrics, e.g., sheets of film.

Ed,

During the separation of sheets for loading does sound good. I always fiddle with making sure I get only one sheet. I'll try to be more careful. Thanks.

Jim