a lot of questionable film

[Charles MacDonald]

Does hi-con non-standard processing like ENR or cross-processing negate much of the issue with base-level fogging?

probably makes it worse!

 

Hi-Con implies entending the development which in turn will bring up the fog level. Cross processing just adds another variable into the stew.

 

Now while we are at it, We have a guideline of .10 above "normal" being a guideline for film that can be condsidered reduced in Quality. IS their a guidling for what is "normal" and does it vary by Film?

[Paul Bruening]

Hey Dominic,

 

Does DI allow more room for fixing occaisional, dubious rolls of stock?

[John Pytlak RIP]

Hey Dominic,

 

Does DI allow more room for fixing occaisional, dubious rolls of stock?

 

DI and telecine offer the opportunity to tweak tone scale, which can help somewhat with fogged film. But any degraining of the increased grain level of fogged film will usually have compromises.

[Dominic Case]

Now while we are at it, We have a guideline of .10 above "normal" being a guideline for film that can be condsidered reduced in Quality.

Where does this guideline appear, Charles? It certainly isn't what I said. Read my post again.

[Charles MacDonald]

Where does this guideline appear, Charles? It certainly isn't what I said. Read my post again.

 

{Within 0.10 on all colours should be OK unless you are particularly critical and you are looking at shaodw detail on a thin negative. Outside 0.10 you are on your own.}

 

 

Sorry if I am interpreting you wrong Dominic! :(

 

I said {We have a guideline of .10 above "normal" being a guideline for film that can be considered reduced in Quality.}

 

I was interpeting your post to mean that within 0.10 away from the original value you should be OK to use the film and still be able to correct to a profesionaly useable result, very much more than that and you risk your project looking like a Music Video where you did not internd it to have that look :P

 

Where did I go wrong?

 

I am seriously curious as the local suplier of ends makes a big deal of giving the reading of their tests right on the can label. which is nice, but I would feel better if that were to tell me something I could relate to.

[Luke Prendergast]

probably makes it worse!

 

But in ENR or bleach-bypass isn't the retained silver going to obscure the fogging to some degree?

[K Borowski]

OK, I've made the point, I think.

 

However, ome labs might use a tolerance of +0.10 on any colour as a "rule of thumb" cut-off. The example quoted was +0.13, +0.16, +0.20, which is clearly way above that level.

 

That's not to say it's necessarily unuseable: it might be OK for some situations, totally unacceptable for others, or to other people.

 

Within 0.10 on all colours should be OK unless you are particularly critical and you are looking at shaodw detail on a thin negative. Outside 0.10 you are on your own.

 

Sorry to highjack this thread a bit folks, but how would fog levels affect reversal films, such as K-14, VNF-1, or E-6 process compared to the somewhat "acceptable" .10 tolerance that you describe? Dominic, in your expert opinion, how many tenths can reversal take before it becomes muddy? Also, if fog is uneven across the three different layers, would this necessitate filtration with reversal process films?

 

Regards.

 

Karl Borowski

[Dominic Case]

By now it should be clear that anyone who actually knows how this stuff works avoids committing to a"cut-off" density.

 

Why would that be?

 

Because we all know that so much depends on the way in which the stock in question is used, that any ruling of "OK" or "not OK" is dangerous. It's been said time and again, even in this thread.

 

I said that some labs might use a guideline of 0.10 above the d-min of new stock, saying that below that figure should be OK.

 

I didn't say that above that figure the film was automatically dodgy.

 

I did suggest that a long way above that figure might still be OK, and might not. Depends on how you expose it, and what sort of scene.

 

There is a crucial difference between saying something is OK on one side of a line, and saying it is not OK on the other side of the line.

[Dominic Case]

OK, now the thread has managed to embroil old and questionable stock, bleach bypass, and reversal all together. Oh boy :blink:

 

Bleach bypass leads to retained silver most predominantly in the HIGHLIGHTS. Age fogging leads to lower contrast in the SHADOWS. Having both together would result in greater highlight contrast and less shadow contrast than normal. Since the highlight end of the range is denser, you still need to decrease exposure (especially if you are going to print). And if you decrease exposure, you are driving the shadows deeper into the fogged part of the curve.

 

"Worse if anything" is about right.

 

The retained silver won't "obscure" the fogging.

 

ENR is a print process. It has nothing to do with the negative. However, in theory, if you expose age-fogged negative so that the shadows are soupy and grainy, then make a print using ENR or some other silver retention process, it's true that you would increase shadow contrast. But in the same way as trying to fix up anything that is underexposed, if you boost the contrast in the print you will also boost the noise, and the (already increased) grain.

 

All that is hypothetical of course. I can't say I've ever deliberately tried this combination of ways to screw up.

 

Finally, reversal. If that is age-fogged, of course it is once again the shadows that are affected, but they are indicated by the d-max of the stock after processing,not the d-min.

 

Since reversal has much less useful exposure range (less latitude) than negative, and therefore little or no tolerance for under or over-exposure, I would say that there is also less tolerance to age fogging.

 

And post-finally, if the colour dye layers are affected unequally in the age fogging, filtering won't help. Filters affect colour right through the tonal range, fogging only affects the shadows. In particular, the totally unexposed areas of the film are most subject to colour shift: and no amount of filtering can change the unexposed areas - think about it!

 

Now - that's answered. Let's hope it stays answered :ph34r: . . . B)

[John Pytlak RIP]

Food for thought:

 

On page 14 of the H-24.01 Process Control Manual, Kodak suggests control limits for laboratories running the ECN-2, ECP-2D, and VNF-1 processes:

 

http://www.kodak.com/US/plugins/acrobat/en.../h241/h2401.pdf

 

For the ECN-2 process, the suggested tolerance for D-min (fog level) is an Action Limit of +0.03 and a Control Limit of +0.05. The processing manual then says:

 

If the photographic effects that are associated with

the plotted control values are not significant, the process can

be considered in control. As the variations become larger,

some limit (action limit) will be reached, at which time you

should take corrective action. If the deviations increase to a

wider limit (control limit) where photographic results fail to

meet your quality standards, suspend film processing until

you can confidently determine the precise cause of the

off-standard process deviation.

 

In other words, if the D-min is only 0.03 density high, the lab should try to correct it. If the D-min increases by more than 0.05 density, the lab may actually stop processing film until the problem is solved.

 

So if a good lab is willing to shut down a processing machine until they can identify why the D-min increases by +0.05, shouldn't you have some concern when your old recan or short-end film has a much greater increase in fog level?