strange fogging!

[neil ferguson]

Hello Gentlefolks!

I am a technician at a small rental house and we have been experiencing a strange problem with a shoot we are servicing. I am hoping someone has seen something similar and

arrived at an explanation. The show has been shooting with a pair of sr3s in super 16 using

3 of the new vision2 stocks. On approx. 30% of the rolls, shots they have a fog in one frame

or sometimes a slightly less dense "ghost" of the same fog in the frame next to it during the last take of the roll. it is always in the last 20 feet of the roll ( ie. 7 feet left or 11 feet ) it usually occurs once per roll, but it has happened that there was two. The fogging is a plus density that

travels through the frame horizontally from edge to edge of the film and covers approx 40% of the image, it is slightly more dense at perf side and is soft at the edges. along with this there

is 6 or 7 perfs along the edge ( behind ) that have the fogging along side the outside of each perf

( like a shadow of the perf) the light appears neutral suggesting white light, but the lab has informed me that in some of the manifestations there is a magenta hue. It has usually been on

400' rolls but apparently on a couple of instances the roll was cut part way through and the

fogging was there too ( again in the last 20'!) the problem happens during a take and there

is no other problem with the image, ie no focus change/exposure etc.

this has occured on both cameras and multiple mags and on three stocks and two

different labs. We are awaiting results of analysis of the neg from kodak, rochester but

in the meantime there is more than a few people pulling there hair out!

If anybody has seen anything like this.......help!

Thanks!!

:huh: :(

[Chance Shirley]

This is a total shot in the dark, but...

 

Is the same person loading and unloading each mag? Could the fogging be caused by something the loader is doing (bending the negative, handling the negative with dirty hands)?

 

- - - - -

 

Chance Shirley

Birmingham, Alabama

[Guest Andy Sparaco]

SR3's have end of roll warnings maybe a flash through the sync fogging lamp from that due to some crossed contacts in the various plugs. Are they using the new slating system that encodes slate info?

 

I have seen 11 pin plugs make Sr's do unexpected things because some set them up incorrectly

[neil ferguson]

Thanks for the response! Yes, Chance, the loader is one constant and I have already advised them to review their procedures, although its happening at just one spot ( usually) thats a little

weird! the crew is going to do a rough handling test to see if it is related. And Yes, Andy,

I've seen some weird stuff with srs, but all the lights in a sr are red to my knowledge, please correct me if i"m wrong, but this fogging seems to be a white light.

 

Cheers!

[Guest hoytevanhoytema]

i think I maight have experieced something simmilar... In our case it was called in dutch "druk sluier", which means something like "pressure fog". It was caused by mechanical pressure. Could be from dropped boxes... pressure applied by the development machine... something that can happen when a lab is starting to work with a new stock?... etc. Basically I believe that it was because the emulsion got somewhere along the way some reaction because of mechanical pressure... hope this could explain your problem

 

 

regards

Hoyte van Hoytema

[Olivier Egli]

I think to remember that in a few cases back here the static electricity of the neg during the processing caused some "sparks" to flash the film. This happens when the film is wound/ unwound too fast or if something is touching the film during this process. I hope I remember correctly...but it would kinda make sense imo.

 

good luck!

[Dominic Case]

IF you are doing tests, have a short roll rewound after you take it out of the camera but before sending it to the lab. If the mark still appears in the last 20 ft, you have a camera/magazine/(un)loader problem. If it is now in the first 20 ft, the lab has a problem.

 

Chance are that you won't see a fogging mark at all on that roll of course:-(

 

My guess would be that it is a lab processing machine problem: some machines have an end-of-roll brake that clamps the end of the film (which could be a few feet in, depending on the lace-up in the darkroom) to prevent a run-out. This has not been a problem traditionally, as (a) any such mark would normally only come into a shot if you run the camera right through to riun-out, and/or (B) because most stocks are unaffected by the clamp. One issue with the newer, faster emulsions is their increased sensitivity to pressure fogging of this type.

 

THe big clue is that you say 30% of the rolls are affected. Labs make up camera rolls into larger rolls for processing, 3 or 4 at a time: only the last camera roll in each group would be affected this way).

 

That's in line with Hoyte's theory too.

[John Sprung]

some machines have an end-of-roll brake that clamps the end of the film (

<{POST_SNAPBACK}>

I thought that labs made up their rolls with a piece of processing leader at the tail, to eliminate this kind of handling issue in splicing the next one on at the feed elevator. Or is that just something that an individual operator may or may not decide to do?

 

 

 

-- J.S.

[Dominic Case]

I thought that labs made up their rolls with a piece of processing leader at the tail

John, I know labs that DO do this :) but I can't speak for every operator on every machine in every lab everywhere. :unsure:

[neil ferguson]

Hello

Thank you guys for the response!, After the camera crew shot a " rough handling" test

and reported that the results were similar to the " problem" they, ( and the lab ) have reviewed

their procedures and along with the production insisting they change camera bodies, the problem

has dissappeared. whether the camera bodies switch has given a convenient out for someone else ,no one involved is stepping forward !

 

Cheers!

[Dominic Case]

the problem has dissappeared.

That's good news.

 

Though it's always frustrating from a diagnostics point of view when everything is changed at once. No-one will ever know where the problem was happening.

 

Next time you rent that camera body out, it will travel with a nagging doubt that maybe there's an obscure problem with it (since the problem went away when you changed it over!)

 

I'd still back my theory though!

[neil ferguson]

Hi Dominic,

So right you are! , but the "show must go on" and sometimes everybody is cagey with

the info they impart, in case they implicate their employer..... It wasn't the first time, and probably not the last time that the answer won't be found.......

But I would back your theory too!

 

thanks again!