Pulling & Pushing color films

[ZorkiKat]

I push Portra 160VC as a rule for my own work. One stop - it's exactly the look I want. I overexpose the negative by half a stop on top of that. For something like this, it's good to experiment for your own tastes because asking advice on forums has some limitations. But in short, yes, pushing and pulling does exist for color films.

But is the processing altered, or is it still standard?

You say that you "Push" Portra 160 VC. But then you add that you overexpose. When you plan to "push" (this happens in developing, not during exposure), you underexpose -and not overexpose- in the camera. The curtailed exposure is supposed to be compensated by extended (thus the "push") development.

However, when you intentionally overexpose, the corrective processing technique will call for reduced development, hence it's called a 'pull'.

A half-stop extra exposure with colour negative films, whose generous exposure latitudes will make serious overexposures still allow for acceptable negatives, does not really require any adjustment in processing.

A true push/pull application for colour film MUST involve some alteration in processing. Otherwise if the application just involves exposure alteration in the camera, it's just simply over or under exposure.

Colour negatives for the most part can't really be pushed by most labs because the typical processing machines (like the Noritsus) are designed to run at a fixed speed only. Sink-top processors or hand tanks may make C41 pushing possible, but usually this will adversely affect the dye densities in the negative.

Chrome films on the other hand do allow for pushing. That's because the first step, where corrective extended or attenuated development can be done, is in BW. Only silver densities form, and this determines how much is left in the film for subsequent colour dye development when the positive is formed.

...This is a set of photos I pushed one stop (160VC Portra) and shot rated at 200ASA:

VC 160 which is officially ISO 160 when pushed one stop should be rated at EI 320. 200 "ASA" is barely a 1/3 stop underexposure from the official 160. And that will hardly need a modification in processing - extended development- to make up for the rather slight underexposure.

 

[LeicaFoReVer]

Thanks Zorkicat for great explanations! yeah I think there is a misunderstanding/confusion btw people regarding push/pull over/under expose. I tried to explain in my previous posts but...your is much better

 

[umcelinho]

i've shot a portra vc 160 roll mistakenly as 400. developed accordingly at the lab, the higher contrast was very subtle and it looks nice, see pic below. i'll try to push portra nc 400 to 800 or 1600 sometime to see how it comes out.. curious

 

[Tim Gray]

Yes, the C-41 development step is 3:15 seconds, for ALL films, no matter what the speed. I can't tell you if the following is industry standard, but it's the times that Kodak gives. A one stop push (or push 1) gets 3:45 s in the dev, while a push 2 is 4:15 s. Many users tell you that a push 1 or 2 doesn't necessarily mean you should expose 1 (or 2) stops less. For example, I've read in several places recommendations for shooting Portra 800 at EI 2000 with push 2 development.

I think this is also how people in the movie industry do things, where pushing of color neg is more common. For example, getting a one stop push on some ISO 500 neg, but rating it at 800. But when you hand it over to the lab, you just ask for a one stop push.

 

[ZorkiKat]

Thanks for the comment Leicaforever

There are/were colour negative films which can be pushed- Fuji and Kodak made some of them. And their tech data indicated this. Usually these were the 'press' type negative films. They usually had lower inherent contrast- the dyes did not get as dense when subjected to extended development.

But some really can't. And extreme applications will likely turn out bad.

Here is an example of ISO 200 film which had been underexposed, not accidentally, but because of poor lighting conditions and the absence of slow shutter speeds in a Zorki camera. EI 800, I believe, and an extended development of about 6 minutes (slightly less than the rule of thumb for a 2X increase in developing time for a 2 stop underexposure) instead of the usual 3'15". I developed the film myself:

The colours shifted. And the negatives were really dense. Scanning does however allow for a greater degree of rectification, compared to optical printing. It even appears that an extra stop is gained when a negative is scanned, isntead of optically printed.

 

[lic4]

I'm sorry ZorkiKat, but I think we might be misunderstanding each other.

I'll be clearer, since I don't think my concept of pushing and subsequent overexposure is mistaken. I come from a cinema background, and we might talk about film (not for better or worse) a little differently than still photographers.

When I shoot 160VC at 200 and push one stop, it means that the lab processes the film as though it is 320ASA film, and on top of that, I rate the film for a 2/3 stop overexposure at 200ASA - I do not tell the lab to compensate for this overexposure. I work in a color darkroom from there, which means I print down this overexposure.

in other words:
1. use 160ASA film
2. shoot at 200ASA (which is 1/3 underexposure)
3. push in processing one stop, stock becomes 360ASA (*push is intentionally chosen for the effect on grain and contrast) 1/3 stop underexposure is now a 2/3 stop overexposure as a result of the push (*overexposed at 2/3 stop intentionally for color)
4. print down to compensate for the 2/3 stop overexposure

I'm not saying this is how it has to be done, but this is a way that one can both push process and rate film at a lower ASA. It's very common practice in cinematography, so I was surprised to read the skepticism. I'm friends with a pro photog here where I am who does a similar variation with his C41 negatives. Portra is a stock that holds up well to push or pull, and this is why I use it. I don't think Kodak Gold or consumer market Fuji stock will handle in the same way.

I know this is redundant, but:
-certain labs do offer push or pull processing of C41 film
-push or pull of C41 can be done intentionally for aesthetic effect, and not just to cover up a mistake in exposure
-intentional overexposure and printing down can be combined with a push or a pull, or it can be done on its own

But is the processing altered, or is it still standard?

You say that you "Push" Portra 160 VC. But then you add that you overexpose. When you plan to "push" (this happens in developing, not during exposure), you underexpose -and not overexpose- in the camera. The curtailed exposure is supposed to be compensated by extended (thus the "push") development.

VC 160 which is officially ISO 160 when pushed one stop should be rated at EI 320. 200 "ASA" is barely a 1/3 stop underexposure from the official 160. And that will hardly need a modification in processing - extended development- to make up for the rather slight underexposure.

 

[ZorkiKat]

I'm sorry ZorkiKat, but I think we might be misunderstanding each other.

I'll be clearer, since I don't think my concept of pushing and subsequent overexposure is mistaken at all. I come from a cinema background, and we might talk about film (not for better or worse) a little differently than still photographers.

<snip>n

That makes it clear now.

I have been reading this from a 'still' photography point of view, and in the context of correcting exposure mistakes, or else forcing the film to produce usable densities in instances where underexposure is inevitable.

I do understand the cinema exposure techniques that involve - and its subsequent pairing to various grading methods to get specific hue or tonal qualities in the print.

One must still consider the inherent differences in cinema colour stock vs the typical still colour film emulsion. Cinema stock can tolerate processing variations, and the processors used to develop negative stock can be varied in terms of processing rate or even output, including the use of modified chemistries to suit the altered effect.

Cine camera stock tends to have a lower contrast index as well- so it's quite well suited for push processing. Its emulsion layers may have been formulated so that they can yield a more balance density in all layers even when subjected to non-standard processing.

Some still camera emulsions- particularly the Press types- do have the ability to be pushed built in.

My points have been:

Push processing not a standard offering by most labs- a typical 1 hour lab catering to Kodacolors and Fujicolors will not do it. A special lab which will do it has to be found.

The typical common Kodacolor, Fujicolor won't usually like it too. When I used to do colour printing in the darkroom, an overdeveloped (pushed) C41 neg would often have serious cross over problems that neutral or fully balanced prints were impossible to do.

And with home-scanning, most scanners don't like overdeveloped negatives too. The dense dyes promote the formation of noise.