Flashing film question

[Chris Keth]

So in some of my reading for class (I'm taking the first class in film production with sync sound) I ran across some information regarding flashing film. So a 100% flash could be found by taking a perfectly white surface and evenly lighting it. You'd take an indicent reading of the surface and then open up by one stop and shoot it. 50% flash would be the same at one stop down, 25% the same at 2 stops down, right?

 

 

I realize this wpould require tests but what would be a normal starting point to find a flash amount that would desaturate colors in a nice way?

 

Anyone have good links to reliable information about it?

[David Mullen ASC]

What a certain percentage of flashing does varies from lab to lab, so while you may decide what a "20% flash" means, it really doesn't mean someone else will do it the same way.

 

So you MUST test to determine what flash percentage you like using the same stocks for negative and printing you plan on using.

 

How the image will be printed affects how heavy the flash looks. A more contrasty printing process will hide or bury more of the flash effect. And how you expose the image over the flash (or vice-versa) matters. If you flash by 20% but underexpose the shot accidentally by a half-stop, then that 20% flash will look heavier. Also a low-con stock will need less flashing to match the flash on a normal-con stock.

 

In general, a 5% to 10% flash is the heaviest you want to go if you are doing normal printing on standard print stock (like Vision 2383.) "Little Princess" for example was all flashed 10% by Lubetski. Any higher than 10% and the image is definitely milky. At 10% and lower, the flash softens the look nicely, lowers the contrast and mutes the colors, without looking too milky. 15% is OK but starts to be a little hazy with normal printing (however, you could use Vision Premier print stock to knock down the flash again but what's the point? It starts to look normal. On the other hand, a mild silver retention is a nice combo with a 15% flash, like a 30 IR or 50 IR level of ENR processing.) I ended up using a 10% to 15% flash on "Twin Falls Idaho" with a 50 IR level of ACE at Deluxe (same as ENR at Technicolor.)

 

I found on "Northfork" when using a skip-bleach printing process, I could get away with flashing the negative by 20% (using a Panaflasher). Any higher and the image definitely looked "flashed" and the blacks were definitely not black.

[Dominic Case]

As David says, the percentage measure for flashing is used in different ways by different people.

 

One measure is the exposure: if as you say, you meter a uniform card, and expose according to that, then you will get a mid-grey on your negative. Every stop you cut the exposure by would be half the percentage exposure: so 3 stops down would be a 12% flash etc.

 

Another measure is the density of the flashed area of negative with no image exposure on it. Either quoted as the percentage of d-max, or as the actual density above the normal unflashed d-min. (Not a percentage, but sloppily quoted as such).

 

It turns out that you normally need to work in the range of 5% to 15% whichver measure you adopt, even though they all measure different things.

 

You need to test not just the exposure to get the right density, but also the effect it will have on the image you will shoot. As well as desaturation, shadow contrast is reduced, so blacks will go to dark greys etc.

[Jonathan Bruno]

David,

 

I'm helping a professor of mine shoot a series of processing tests for his Cine II class at Chapman University. We are shooting six different processes int. day/night and ext. day/ night. He wants to show them the generic effects of flashing the film. What percentage would you suggest for this test, and how would that translate to shooting the grey card, seeing that we don't have a panaflasher system.

 

Thanks,

 

Jon Bruno

[David Mullen ASC]

You'll see the flashing effect the most in blacks, so shoot a shot with some contrast and shadows, plus the greyscale. Most people never flash more than 20% -- talk to your lab about having them flash different percentages and how they do that, do they need every version on separate rolls, etc. Otherwise, see if you can scrounge up an Arri VariCon device, or do the flashing yourself using double-exposures.