Pushing a film...results?

[isfint]

Hi everybody,

Beginners thread....

What is this thing called "pushing a film"?
Does it mean that you take a 800 ISO en set your meter on 1600?
Why should you do that? And when do you know that you have to set it on ISO x?


I got a Leica M4 with the MR-4 meter (summicron DR 50mm F2). Yesterday I loaded my M4 with a T-max 3200. I use my lightmeter for aperture and shutter speed readings. So, why and when should I set the MR-4 meter to, for example 1600?
As I just got this camera I have never developed a film. I'm waiting to buy some darkroom stuff.

THX

Olivier

PS This may be a stupid thread, but hey, I'm a newbie 😉

 

[Goodyear]

(This is the unscientific version - search for Roger Hicks' old thread pointing out that what is commonly referred to as a puch or a pull technically isn't. Here we go for the popular usage.)

What you can do (with B&W, or to a lesser extent E6) is either under expose a film and over develop it to compensate ("push" it), or overexpose it and under develop it to compensate ("pull" it).

So if I had a roll of Neopan 1600 (this is one I use in this way quite often) that wasn't proving fast enough for me, I could pretend (to myself and my meter) that it's actually a 3200 speed film, so it's getting udnerexposed by a stop. Then, when developing, I increase developing time to compensate for this.

Of course, there are trade offs. The Neopan gains much greater contrast and greater grain (common results of pushing), but I actually really like the look from this (here's an example).

Pulling is more commonly used to obtain a certain look from a certain film, becasue it's rare to actually desperately need less speed in the same way you might require more. I've never done it.

 

[kaiyen]

To add to Mark's post...

1 - you can't actually increase film speed, in any given developer. Film speed is defined by shadow detail; no matter how long you leave it in the developer, a film (say, Tri-X) in a particular developer (say, Rodinal) will always have the same speed*.

2 - However, what you can do is to overdevelop enough so that your midtones come out right. In other words, you aren't actually making a 1600 speed film into a 3200 speed one. Rather, you are pulling the midtones and highlights up such that you can get a usable negaive/image.

3 - Therefore, what you're really doing when push processing is increasing contrast. You're making the whites whiter, and the mid greys brighter greys, which helps with critical midtones such as skin. You're technically making the blacks blacker, too, but since you've lost so much shadow detail already from lack of exposure there isn't much of a difference.

4 - Conversely, when you pull film, you're reducing contrast. If I shot Tri-X at, say, 200 and developed accordingly in a developer that usually gives me 400, I'd have reduced the contrast of the resulting negative considerably.

I think I've flown off into needlessly-technical land. If so, just ignore me.

allan

* - I realize that technically shadow density does go up a bit as you overdevelop.

 

[Jamie123]

what if one doesn't develop the negs by oneself? are there labs that will push a film upon request?

 

[kaiyen]

Good labs will do that, sure. But you need to make sure they're using a developer suited for it. Some labs will just use a color machine but with a really active developer in it. You can't do controlled pushing with that.

allan

 

[ruben]

And worst BW commercial labs will prepare a mix with different films at different ISO rating and "average" the soup resulting in bad processing for all.

Cheers,

Ruben

 

[Graybeard]

Most film and developer manufacturer;s data sheets will provide time/temperature data for processing films at different "effective" film speeds. Kodak has a really extensive listing for Xtol (film developer) which is the one I use.

It has been my experience that Tri-X can be pushed one stop (to ASA800) with little evident loss in shadow detail - that extra stop can be really handy to allow shooting at a shutter speed where camera shake isn't a problem. I understand that Fuji Neopan 400 can be readily pulled to ASA200 to improve shadow detail and the grey scale range - haven't tried this myself.

You'll really want to do your own processing if you'd like to explore the possibilities of manipulating apparent film speed or experimenting with B&W developers other than D-76 (it is unlikely that a commercial processor uses anything else, if he does B&W at all).

 

[Frank Granovski]

Ilford HP5+ (400 asa) pushes well 1 stop (800 asa). With Delta 3200, I usually pull it back 2 stops (800 asa), but I like the HP5+ results better.

 

[isfint]

Film

Film

Hey guys,

Thx for the tips! I'll do some test in the near future!

Olli