B&W films capacity to retain its latent image over time.

[Samuel Hotton]

Does anyone know of a chart or table showing different B&W films ability to retain a latent image over extended times? Sort of a question for those that keep exposed film in their camera for several months before having a chance to process it, or while traveling without a place to process it. For example, I feel that Ilford Pan f plus does not retain its latent image as long as Plus x.
With thanks,
Sam Hotton

 

[cliveh]

The ability of films to retain latent image over time is usually pretty good.

 

[clayne]

I'm still interested in a source on this PanF thing. Noone has ever provided anything substantial other than hearsay.

I do believe there is some studied data out there on latent image keeping of silver halide films - but one would probably have to hunt around for it.

 

[Lowly]

I had some film I hadn't developed in a few years - shot at the same time and kept in the same conditions (a drawer in the house). Finally developed them - Tri-x turned out fine, Pan-F not so much. That's my experience, and since this is the internet, I guess it's hearsay

 

[polyglot]

I've personally had the Pan-F issues.

Here's Simon Galley's (of Ilford) (there was a url link here which no longer exists) in a previous thread.

 

[Samuel Hotton]

Simon Galleys "Ilfords" response seems to bear out what I have experienced over the past ten years.
Sam H.

 

[darkosaric]

I have found old film in agfa isolette that I bought - I think film was minimum 20-30 years old: it developed without any problem (see attach). Some base fog because I used Rodinal semistand method, but if I had used HC110 dilution B - I belive it would be even better.

 

[GRHazelton]

I remember finding some exposed Plus X that had ended up in my attic. I processed it but only got faint, ghostly hints of images. Stored at normal room temperature it might have been okay. I've no idea how old it might have been.

 

[Moopheus]

The longest I've personally experienced was a roll of Tri-X that was left in a drawer for almost 30 years, and was still pretty good when processed. I don't recommend leaving film for 30 years, but a few months should be okay. I should say, I've left color film that long without issues.

 

[mnemosyne]

There was some rather general but still helpful information posted by Ilford's Simon R Galley a couple of years ago in this forum. IIRC, firstly, the slower the speed, the worse are the latent image keeping abilities and secondly, modern tabular grain films like Delta or Tmax have better latent image keeping abilities than classic emulsions. If it takes you a very long time to fill a roll of film, your best bet would be Tmax 400 or Delta 400 and you should avoid films like Pan F.

 

[ROL]

Noone has ever provided anything substantial other than hearsay.

Noone's "facts", substantial or otherwise, have long been the subject of reasoned debate. Noone should be taken lightly. Noone can be trusted.

 

[clayne]

I was meaning some kind of scientific explanation...

 

[Samuel Hotton]

I was hoping Photo Engineer might be able to shed some light on this topic. Surprising that the manufacturers have not the tested Latent image retention, much as the testing of Reciprocity failure and then publishing the results.
Sam H.

 

[cliveh]

As you can’t see a latent image, you can only test for its existence by development. But it may be here at one minute and gone the next. It has in fact a quite magical quality.

 

[john_s]

There was some rather general but still helpful information posted by Ilford's Simon R Galley a couple of years ago in this forum. IIRC, firstly, the slower the speed, the worse are the latent image keeping abilities and secondly, modern tabular grain films like Delta or Tmax have better latent image keeping abilities than classic emulsions. If it takes you a very long time to fill a roll of film, your best bet would be Tmax 400 or Delta 400 and you should avoid films like Pan F.

I have developed Tri-X something like 5 or 6 years after exposure and it looked good. It might have been a bit better had I developed it earlier, of course. I have some 4x5 sheets of APX25 exposed 4 years ago. I'm gong to develop them in the next few weeks, so i'll post back. (The film was already 10 years after use by date when exposed. I was relying on the long life of slow films, pre-exposure life that is)

 

[Moopheus]

I was hoping Photo Engineer might be able to shed some light on this topic. Surprising that the manufacturers have not the tested Latent image retention, much as the testing of Reciprocity failure and then publishing the results.

Presumably they have done the tests (Mr. Galley says they have), but they're not going to encourage users to try storing exposed film for long periods of time. I mean, when they stamp a date on a box, it means, this is the time we guarantee the film will meet these specs, not, this is the time you might still get some usable image if you want to chance it.

 

[Samuel Hotton]

I think some empirical testing is in order here. To expose several types of film with 36 identical and controlled exposures, use my processing and over a period of extended time, process segments of these films. This way I will be able to actually see if and how much the image degrades visually in real life with the different films.
Sam H.

 

[clayne]

(there was a url link here which no longer exists)
(there was a url link here which no longer exists)
http://www.google.com/patents/EP0488030B1?cl=en
http://www.google.com/patents/EP0698814A2?cl=en
http://books.google.com/books?id=3sMfJ-CMm0wC&pg=PA94

I don't think anyone actually knows the exact answer to this.

 

[StoneNYC]

(there was a url link here which no longer exists)
(there was a url link here which no longer exists)
http://www.google.com/patents/EP0488030B1?cl=en
http://www.google.com/patents/EP0698814A2?cl=en
http://books.google.com/books?id=3sMfJ-CMm0wC&pg=PA94

I don't think anyone actually knows the exact answer to this.

I suspect that the reason no one knows is they don't know how exactly Ilford makes their PanF+ as its a proprietary info thing... The reason for the image failure is tied to how they make the PanF+ that they don't want to share with other film companies...

Just know it happens and you're safe the first 3 months...


~Stone | Sent w/ iPhone using Tapatalk