Edge flash on S16

Jeff Clegg · February 4, 2007

I recently shot a project on an Aaton LTR 7 and had some odd flashes come up on the right side of the screen, rythmically flashing and disappearing. They happened only in one setup, and then didn't happen again on the next setup (same roll). I am trying to track down what it might be to make sure it doesn't happen again. I've included a link to a short clip.

Link to video clip: http://www.thejlnc.com/WD%20Edge%20flash1Mbps_Stream.mov

Thanks,

Jeff Clegg

DP

NH

Edited February 4, 2007 by Jeff Clegg

K Borowski · February 5, 2007

Well, it's obvioulsy fog of some sort. Of the experience I've had with Auricon mags, which are the dual chamber rather than single chamber, edge fog from light isn't as rhythmic, it's regular. Did you talk with the lab? It might be pressure fog people sometimes complain about. Did you have all of the magazines checked out before commencing your shoot? I see that you're shooting at night. I would not use that mag in the daytime for sure, as light fog can show up little to not at all in dark conditions, indoors or outdoors at night, but become VERY SERIOUS in brighter environments. One way of testing the mag is just to tape a piece of unexposed film in there, attach it to the camera, tape it as normal, and shine light on it that is of roughly the same duration and intensity as you'd get shooting outdoors in daylight or indoors under bright studio lights (in other words not super super close light right by the magazine, something comparable to what you'd expect during a shoot). Give it as close an exposure as possible to what you'd see under actual shooting conditions, then process for fog, maybe the lab'll do it for free, or you can do it with just B&W developer, as you're going to get hopefully blank film if there's not a problem. You can get a package of Dektol and a some stop bath for under $20 if you want to do the test yourself. You can just develop in a cup and turn the lights after 30 seconds of stop bath. Another test you could do would be with a piece of polaroid film if you have access to a polaroid back that'd fit in the mag. Run the same procedure and then just unload the back in the dark and pull the film through the roller to start the processing. Test with a comparable speed film, I think they have a 400 speed color. Really anything's fine except that 4000 speed they have.

Regards,

~Karl Borowski

Jeff Clegg · February 6, 2007

Thanks, some very useful tips there. I am curious about pressure fogging as I dont think I have heard too much about that. I shot a light leak test and am having it processed now. Just very confused as to why it would happen on only part of the roll.

Thanks,

Jeff clegg

K Borowski · February 6, 2007

Thanks, some very useful tips there. I am curious about pressure fogging as I dont think I have heard too much about that. I shot a light leak test and am having it processed now. Just very confused as to why it would happen on only part of the roll.

Thanks,

Jeff clegg

I haven't heard much about it either. I've never seen it, but I haven't shot voluminous amounts of motion picture film either. It has something to do with the film being pressed too tightly between the rollers (I think) which causes some sort of fog in the emulsion.

It'd be best if someone on this forum like Dominic Case could address the issue, as he runs a lab and is probably the resident expert on actual processing issues.

My guess, if it is just light fog and not another variety, is that there was a beam of light that hit the magazine at the right angle to cause fog. I've had a few problems with light leaks with wedding photography (very luckily nothing that wasn't covered by the main camera), and there's a tremendous variation between the amount of fog you get outdoors, indoors well-lit, and indoors dark. Shooting indoors in a dance hall, there was almost no fog, as opposed to the fog outdoorsin bright sunlight.

Another possibility is that, when the film was stopped between shots, the section showing the fog received enough exposure to cause noticeable fog, whereas the rest of the film passed through the affected area quickly enouth not to suffer any ill effects.

~Karl Borowski