Beating a dead horse?

[nealjpage]

I've looked through the archieves to find the answer, but I couldn't find it. So I'm going to ask a question that I'm sure has been asked a billion times. *takes a deep breath* What is the process for "pushing" film? I understand that you trick, for lack of a better word, the film into thinking it's faster then it really is, right? So how do I do it?

Pretend I'm at a concert and I've got a fresh roll of Neopan 400 to load into my K1000. It's kinda dark and smokey in the bar and the lights from the stage don't really help me out much. With the camera set at 400, the shutter speed slowed way down, and the apeture all the way open, the light meter barely moves. What do I do? Do I set the camera's film speed selector to 400 or do I set it to something higher, like 1600? This is the part that I just can't wrap my head around.:greenpbl: At least not yet.

From there, I think I got it. I look up the time and temp for Neopan 1600 and develop like it's 1600 speed film, right? Or is that wrong?

Thanks for listening to my question. I suppose I should take a class or buy a book, but I haven't. I just know that my film is capable of doing more and I'd like to take every advantage of it. So any advice I could get on the issue would be greatly appreciated.

 

[Hertz van Rental]

Pushing a film is just treating the film as if it has a higher ISO than it is rated at.
You do it by changing the ISO on the meter.
What this does is to under-expose the film.
A 400ISO film pushed to 800ISO is under-exposed 1 stop.
A 400ISO film pushed to 1600ISO is under-exposed 2 stops.
If you process normally then they will come out as under-exposed so you have to compensate by increasing the development time.
For most B&W film/dev combinations try 20% increase in dev time per stop.
Fast B&W films can be pushed more with better success than slow films, primarily because the grain in fast films is bigger and so has a better chance of being hit by light.
The whole process of pushing is just exploiting the latitude of the film. It will, however, affect contrast and increase grain size.
C41 can be pushed a stop or two with varying degrees of success.
It is best not to push E6 - but you can get away with 1 stop increase.

 

[nealjpage]

Cool. I'll give 'er a shot this weekend as I've got a concert to go to.

 

[nealjpage]

Well, update time. I took about three rolls of ISO 400 film and exposed it as 1600. Took my first roll to school to develop and was dissapointed with the results. Film was Agfapan 400 and I developed for 20 minutes at 68 degrees. Images were very faint, in fact several frames were non existant. Did I do something wrong with development time or fixing? Or is Agfa not good film to pull?

 

[Hertz van Rental]

What was the recommended time for your developer with the film at it's 400ISO rating?
And what agitation did you use (amount and timing)?
Also need to know the ambient temperature of the room you processed in.

 

[nealjpage]

Recommended time was between 11 and 14 minutes at 68 deg. After filling, I agitated for 15 seconds or so while tapping tank on sink to dislodge air bubbles. After that, I agitated every 30 seconds and inverted tank every minute, which is what I do when developing at ISO 400. I'm not sure about the ambient temperature down there; room is in the basement so I would guess temp is about 65 or so.

 

[Hertz van Rental]

20 minutes would be about right.
Agitation should be for the first 30 seconds then agitate for 5 secs every 30 secs.
Ambient temperature dictates how quickly the dev tank cools. As the developer gets cooler the developer works slower. But if it's not far off the dev temp then it shouldn't be causing a noticebale problem.

Have a look at the rebate markings on the neg (frame numbers and film code down the edges).
If they look thin then it is an under-development problem so something else is wrong.
If they look reasonably dark - darker than the negs themselves - then it's an exposure problem and not processing.

 

[nealjpage]

So it looks like it's not processing--rebate markings are nice and dark and clear. I must not be using the camera correctly. Hmmm...

 

[Hertz van Rental]

Might be that you aren't metering properly. But the first thing to check is the meter battery. Should be replaced at least once a year. Make sure the contacts are clean too.
From the description og the negs and rebates sounds like you are about 2 stops underexposed (for 1600ISO).
Whenever you get a problem like this you just go through the list in a logical fashion and eliminate until you isolate what has gone wrong.

 

[nealjpage]

Meter is working fine, or so it seems. Set ISO at 1600 then adjusted aperture and shutter speed accordingly. I guess at this point it doesn't make any difference, does it? I've got two more rolls that I used through the same camera in the same way. Is there something I can do to salvage the two remaing rolls? They've got some good pictures on them...

 

[Hertz van Rental]

Do a clip. You'll loose a couple but you should salvage most.
Bad news is they'll be somewhat grainier and the contrast will be off but it's better than nothing.
Clip some of the film off one roll so you've got 4-6 frames on the strip.
Do a modified process.
Adjust for an extra 2 stops under so I reckon 28 minutes is a good starting point.
Evaluate the negs and then process the rest accordingly.

 

[nealjpage]

Well, did it for 30 min at 68 degree. Pretty much the same. Oh well. Live and learn, i guess. Any idea what I might've done wrong?

 

[Hertz van Rental]

I don't have the sensitometric data for Agfa films - it's almost impossible to find - so I can't really be sure. It could be that you have under-exposed too much and exceeded the latitude of the film.
Pushing film just utilises the latitude that is built in - but there are limits.

 

[nealjpage]

I got the same result from two rolls of Ilford, too. Maybe it it the meter in the camera...

 

[Hertz van Rental]

I'd try putting in a new battery for a start. You should change meter batteries at least once a year. You don't always notice that they are going at first unless you can do a visual exposure assesment. Check it against another camera or a hand-held.