Basic developing questions - not again!!!

[Phantomas]

Hi people, got some silly development questions to ask. Tried to search them here, to no avail, probably because they're to silly. I've been developing myself a few months and always had these on my mind, afraid to ask, so here we go, go easy on me 🙂


- What's the effect of developing slightly longer than recommended times? Do final results look underexposed or overexposed? I tend to think underexposed, as the scans appear darker in my case. But on paper it sounds like they should be overexposed. Would overdeveloping film rated at it's speed be pushing or pulling? My head hurts.

- Is there such thing as "overfixing"? How much harm is there in fixing let's say 30% longer than recommended time (ignore film-leader test here) just to make sure the film is fixed? I believe and I read that there's no harm unless one goes way overboard. So, is it OK to overfix to be on the safe side or is there any benefit to sticking as close as possible to actual (necessary) times?


The first question especially hurts my head. I use a lot of expired film and have a habit of rating it at a step lower speed (fresh film often rated at native speed). Taking that and developing times is confusing me at the moment because I'm not thinking clearly right now, haven't slept much past few nights, shaking developing tank catching up on a huge backlog.
Thanks for any advice.


PS: Oh, and while I'm at it, where can I find some rules of thumb on "stand-developing"? You know, recommended times for particular films in particular chemicals? I find a lot of fragmented (and often conflicting) info, but no concise list with at least basic selection of popular film/developer combination.

 

[Al Kaplan]

Developing longer increases contrast by increasing density mostly in the highlights. It does very little in the shadows. Often called "pushing", it can give you a useable negative in dismal light.

Film doesn't just roll over and die on the expiration date, nor lose half of its speed either. B&W film should be OK for a year or two past date, and even more if stored in the fridge or freezer. If you have bunches of one type and age of film just run some tests.

I'll let somebody else tackle stand development.

FIXING can be over done. There's no need for it and fixer will disolve a bit of the image after a long enough time. At "twice the time to clear" your film IS FIXED.

 

[bojanfurst]

Okay here is a part of the answer to your question: http://www.digitaltruth.com/devchart.php

Now take that as a guide, of course 🙂

If you expose and develop film at the higher ISO rating than the nominal speed (e.g. 400 film at 1600) you are pushing the film. Do it the other way and you are pulling 🙂

Yes, you can 'overfix'. The film is not completely 'fixed' until it is properly washed. No harm done if it stays in a few extra minutes, but don't overdo it. However, keep in mind that if you are reusing fix, you do need to add extra time with each usage.

Hope that helps...

Bojan

 

[rxmd]

- What's the effect of developing slightly longer than recommended times? Do final results look underexposed or overexposed? I tend to think underexposed, as the scans appear darker in my case. But on paper it sounds like they should be overexposed. Would overdeveloping film rated at it's speed be pushing or pulling? My head hurts.

It's very easy. You have a film rated at a certain sensitivity, the speed it says on the box. With your developer you have a certain development time that it takes to produce this speed.

If you spend more time developing, you're allowing the developer to work longer and more aggressively. Effectively, you're producing more contrast. The effect is that you are developing the film at a higher sensitivity than what is written on the box. This is called "pushing".

If you spend less time developing, you're not allowing the developer to work to the end. Effectively, you're producing less contrast. The effect is that you are developing the film at a lower sensitivity than what is written on the box. This is called "pulling".

Now if you have old film, the difference is that the film has lost sensitivity, so that it no longer has the speed it says on the box to begin with. So your 100 ASA film is now only a 50 ASA film, for example. If you spend the time listed in your development chart, you now only get 50 ASA out of it, and if you exposed it at 100 ASA it will be underexposed. In order to get 100 ASA out of it, you now have to push it and spend more time developing.

- Is there such thing as "overfixing"? How much harm is there in fixing let's say 30% longer than recommended time (ignore film-leader test here) just to make sure the film is fixed? I believe and I read that there's no harm unless one goes way overboard.

Exactly. If you leave your film in the fixer for two weeks you can expect trouble, but 30% or so or 100 or 200% are no problem whatsoever.

 

[Phantomas]

Couple of years? I'm shooting Isopan from 1969 🙂 (Great results by the way).
I understand the mechanics of pushing the film when it was rated at higher speed in the camera, was just confused about overdeveloping it when rated at native speed.

 

[ed1k]

Well, push processing is technically over development when you rated film at higher ISO than it actually is, so you compensate for low negative densities because of the lack of light went to film. Just over development when you rated film at nominal ISO, so the film got exact amount of light as it should, gives you dense (dark) negatives with increased contrast; and it is considered a fault in processing. The overdeveloped negatives might look as overexposed, however it is not completely similar. The resulting contrast is different despite they both might have lack of details in highlights.