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Why does unexposed film get fogged with age?

Let's see:
2038 - 2009 = 29 years.
Y2K - 29 years = 1971.

I wonder how many computers running in 1971 were still running in Y2K?
 
Will there be any software or hardware in use now that will be compatable with what will be used 30 years from now?LOL!

Given this, perhaps you guys should think of getting a big liquid nitrogen dewer and start getting liquid nitrogen deliveries twice a week. Just remember to not drop the rolls while the film is still cold or it will shatter.
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Kirk
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I love telling new students after they dropped their roll of film on the floor, "Oh, no! Now all the silver on your film got moved around and your negatives will be blurry!"

Vaughn
 
Please see the A in APUG......This talk is making me ill.
 

By the way...you may be the only APUG member who actually knows what my user name means! I wonder if you caught it...

Even if our beloved fast film was surrounded with only a single tenth thickness of combined shielding, it would make the film last ten times as long (assuming gammas are the most penetrating of all film-fogging rays present here on Earth). I am thinking a steel and ice layered box (lead = too heavy and too expensive), stored in a large commercial top-load freezer. Additional shielding outside of the freezer would be fairly easy to implement (though gammas are squirrely little buggers and will find any flaw they can in a shield, so it would have to be of reasonable construction quality).
 
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There are two issues with it:

1) The desktop is not the only computer, there are industrial computers all over the place, some of which are in utility vaults and other places where they have never been updated, even though they have been running and working since the 1970's.

2) There are many places where they use future dates, where they may run into issues much sooner then 2038, for example a railway car put into service today has a life span of at least 30 years, so the projected rebuild or retirement date will be 2040, an issue for 2 years already.

I think a bigger issue today is the fact that we will probably be dealing with a severe oil shortage by then, so computers dependant on oil fired generating stations, will be a bigger problem, long term.

Not that this has much to do with film, I think we will still be souping black and white film in 2038, I may not be, I'll be 77 if still around then, although there are guys in their 80's still doing it today, so it is a possibility. I do need to pick up a bottle of HC110 to soup a roll of FP4 that is here.....
 
Kirk Keyes said:
Let's see:
2038 - 2009 = 29 years.
Y2K - 29 years = 1971.

I wonder how many computers running in 1971 were still running in Y2K?
Click to expand...

You need to define computer, there are computers everywhere,
many of these don't look like computers, but are computers none the less, most are not on a continuous upgrade cycle, either. They get replaced for other reasons, like parts not being available, although if you have 2 old units break down, you decommission one and use parts from it to fix the other. You keep doing this, until you run our of units to decommission.

For example telephone switching equipment, some of that certainly lasts 30 years, probably much longer, considering that tone dialing has been around since the 1960's a switch that uses Unix time stamps could easily have been built in 1971 and still be in service. No reason it will not still be in service in 2038 either. Although that could be dealt with the same way a lot of software deals with Y2K, the billing system simply converts the 32bit int into a 64 bit int and adds a certain value to it that represents a specific date. Much like a lot of todays software assumes a year less then 50 is assumed after 2000 while a year greater then 50 assumes a year before 2000.

I expect this to be a bigger issue for digital cameras then film cameras though, not sure the date format used in digital file formats.
 

We are already way off topic, most digital cameras use the FAT file system which uses a different coding for dates.

Many Computers used to control stuff don't need the know the current date.

Data bases may not use the time_t as their representation, if for no other reason than it does not handle dates before 1970.

Any other discussion of date codes in APUG should probably be confined to interpreting the X dot X or Dot Square Triangle code on the edge of an old strip of negative film.
 
BetterSense said:
I have heard and experienced that old film becomes fogged with age.
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Part of age fog is just random. If I remember correctly, free floating interstitial ions in the silver halide crystal will randomly attach to sensitivity specks. Generally, the electron won't remain for long, but if a certain number are attracted, then it will form a stable latent image. Since the process is random, the fogging will be even throughout the film. It's a part of the Gurney-Mott hypothesis for latent image formation if you're interested in looking into it further.
 

time_t is a signed integer, so December 31, 1969 at 23:59:59 is -1, so it can handle any date back to about 1901. Sufficient for most purposes.

While FAT does use a different format, what is the internal date/time representation within say a JPEG file? If it uses time_t then it becomes an issue in 2038. If it doesn't it does not matter.

Funny thing is, my Konica FC-1 (35mm SLR) had no problem with Y2K and I doubt that 2038 will cause it grief either. I fully expect the FC-1 to still be in service in 2038.

The time_t date/time process was adopted widely because it's a simple counter, most computers use an ADAC timer chip that advances the counter once per second, as a memory address. When you need a date and/or time software reads that address and simply converts it into a real date/time for display purposes, I would expect a lot of digital cameras do use it. I don't expect that any digital camera currently being used will still be in use in 2038 though (including my Canon Digital Rebel), so the point may be moot.

It would be nice to be able to figure out the type and age of some of my negative strips though that have the silly bar code thing along the bottom. While I do know how old most of them are due to my filing system, not so sure about the manufacturer and model for the colour stuff. The B&W I have mostly figured out, it helps that the film rebates today are largely the same as they were 30 years ago, when I started.
 

wogster, on a related note, I've been hoping for an nstime_t for a while now. Purely nanoseconds since the epoch (let's say 2000:0101:0000). An 8 byte would give us huge amounts of range, even with nanoseconds (I think it was 500+ years or so). Would be nice not having to then monkey around with struct timeval/timespec, etc. and just use a flat nanosecond counter.
 

The information on the other edge may be more useful, although it does vary by maker. There are charts which explain that bar code, which if I have read correctly contains a code for the film type, and also the frame number.

US Patent 5,164,574 has some of the details.


As afr as the Time_t, see the wikipedia entry, behaviour for negative time is system specific. http://en.wikipedia.org/wiki/Time_t
 

Not that any of this has anything to do with analog photography what so ever, so we should stop now.....:rolleyes:
 

I have some colour films that have a simple code like 54F2 and SA47, no manufacturer, no model number, nothing. Was hoping the bar code would be some help in figuring out what they were..... Mind you a few stored in good conditions are now so faded as to be pretty much useless, but.....

At least Kodak had a couple of codes for Tri-X and a couple others for Plus-X, that were relatively well documented. Ilford was more helpful, FP4 simply said FP4, HP5 would say HP5. Some of the newer colour films do that now, as well. I don't shoot much colour film anymore, but am returning to shooting B&W again.....
 

Kodak did use the film code number for a while "Kodak 5031 film" but they usualy used the name or an abbreviation . The dot in the word "sa'fety" or "Ko'dak" indicated where the film was made - or at least packaged.

If it is Back and white film, most have at least the name and or type shown somewhere in the edge code. It may be the brand name or just the speed particularly if you are dealing with private label stock. Fuji private label stock has something like 400-36 in small dot matrix type on both their color and black and white private label.

AGFA for the last several years had a BIG edge print, which is now showing up on some Ilford stock as Harmon apparently bought one of AGFA's packaging lines out of the liquidation. the private label Agfa just had the speed (400/27) for example. (although I recall buying some COSTCO private Label AGFA which had the costco brand on the edge.

If you are looking at colour film, the makers would put coloured bars in the perforation area to indicate what version so that the negative could be printed on the right settings. Ferrania went as far as symbols in that area.

Forte put the emulsion number in the space between the perfs on the lower edge of the film, where you will see it on Classic Pan, Forte, or Arista edu Value Line.

Once you identify one makers way - you can often spot it an other rolls. (but watch for things like the packing line changing hands.)
 

Great information. I think I might be inclined to create a page with pictures of roll marker codes so that we can have more to correlate from. I'd figure all it will take are just scans or digital shots of a few frames from a strip along with the manufacturer/emulsion type.
 

I don't know why if it's Fujifilm Superia 200 that they can't put that in the upper rebate which is often empty or just has some goofy numbers in it (too short for an emulsion number) that mean nothing to anyone other then the film's maker. Ilford has managed to put FP4/HP5/PanF/XP2 in the rebate forever.

If it's a model number, why can't companies publish the numbers and what they correlate to? About the only way to do it, is to write down what the film is when you send it off, and then check the rebate on return and match things up, doesn't help if you took the photos in 1989 though....
 

Fuji Puts the speed and # of exposures in the edge print ie 100-24, 100-36, 200-24 etc.

They do this even with "private label" film which of course they don't want to put their name on. Film sold under their own brand does say FUJI every few frames. They also put the emulsion number on the film.

BTW1

I just got a roll of Fomapan 100 bulk, and it has no edge print that I could detect.

BTW2

I noticed that the Legacy Pro 100 film looks to be Fuji made , (same cans, printing of expiry date on box, same general edge print) but the film base seems to be a different colour My darkroom work is not scientific enough to be able to spot other differences.
 

Aside from any minor base differences (why the sadness?), LP100 is *definitely* ACROS100.
 
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