push/pull vs rating stock

[allnetfilms]

I am a newby to using film. When I derate or uprate a stock say I rate 500t as 320t or go the opposite direction. I'm trying to understand what happens when the negative gets processed. I'm also trying to understand what happens when I request push and pull processing. Is it effectively the same thing? Not knowing any better I'd say yes but I see people combine the two frequently. I just need a concise article or some insight from one of you gurus about how this works. it gets processed. and trying to get used to rating stock differently and understanding what the lab does if you tell them to rate the stock differently vs push/pull. The guy at the desk at Fotokem had no clue.

 

Thanks!

 

-D

[Dan Salzmann]

This topic has been extensively covered on this forum-a little research is called for.

[David Mullen ASC]

Exposure and processing are DIFFERENT things. You under or overexpose a stock whatever way you want and you can get it processed normally, or push or pulled.

 

MOST people who rate a 500 ASA stock at 320 ASA do so for the extra density (overexposure) so they want the film developed normally, so in this case, the resulting negative will be 2/3's of a stop too dense. Then in printing or telecine transfer, they correct this to normal brightness.

 

But one could overexpose by one stop (rate 500 ASA film at 250 ASA) and then ask the lab for a one-stop pull-process, resulting in a final negative density that is normal, not one stop too dense.

 

You can do any combination of exposures and processing. You could expose normally but ask for pull or push processing.

 

The lab just wants to know if you want the film developed normally, or if not, how many stops you want to pull or push process it. How you exposed the film in relation to that processing request is your business. They don't care if you shot on '18 instead of '17 and whether you rated 500 ASA at 320 ASA. There's just one process for all the color negative stocks -- ECN2 -- and they can do it normal, push, or pull (not including the special processes like skip-bleach.)

 

It helps to shoot a gray card or scale at the head of the roll at the ASA rating you are using, so if the negative ends up deliberately overexposed but you want the image to be brought down to a normal brightness in printing or telecine, if the timer or colorist corrects the overexposed gray scale to look correct, the the following scene will also look correct.

[allnetfilms]

I know this topic has been covered but from various angles. But I needed a declarative statement. Your answer was succinct and complete. Thanks so much David!

[allnetfilms]

But one could overexpose by one stop (rate 500 ASA film at 250 ASA) and then ask the lab for a one-stop pull-process, resulting in a final negative density that is normal, not one stop too dense.

 

<{POST_SNAPBACK}>

 

 

I know the effect of changing the rating and the effect of pulling or pushing. But would what's described here have no effect ultimately?

[David Mullen ASC]

I know the effect of changing the rating and the effect of pulling or pushing.  But would what's described here have no effect ultimately?

<{POST_SNAPBACK}>

 

Overexposure by one stop & pull-processing by one stop, ending up with normal density, will lower contrast, reduce graininess, and make the colors a little more pastel. You will lose a little overexposure detail but gain more shadow detail.

 

Overexposure by one stop & normal processing, ending up with one stop extra density, will require higher printing lights to return the image to normal brightness in the print; you will get deeper blacks and thus slightly more contrast, richer colors, less graininess. But this is all related to how it will look printed. For telecine only, there is less benefit to overexposure other than some grain reduction and improvement in shadow detail.