In last week's issue of the New Yorker, Rebecca Mead wrote:

The last facility that processed Kodachrome film, which many mid-century photographers used, ceased to do so in 2010. An undeveloped roll of Kodachrome found in a late photographer’s archive today could contain an unlocked masterpiece that may never be seen.

Is this true? If I understand correctly, Kodachrome can still be developed in black-and-white, so you could at least get a diminished version of the masterpiece.

But would it be possible, in principle, for a film format to be so thoroughly lost to history that you couldn't get any image out of the negatives whatsoever?

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    \$\begingroup\$ You might be interested in the Museum of Obsolete Media. The problem you describe affects all media types, not just film. \$\endgroup\$
    – Caleb
    May 22, 2017 at 16:34
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    \$\begingroup\$ I take exception to the phrase "get a diminished version"- an 'alternate' version would be more accurate. \$\endgroup\$
    – Alaska Man
    May 22, 2017 at 17:20
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    \$\begingroup\$ @Agent_L OS X doesn't use activation servers, and you can install a fully functional copy from install media with no help from Apple's servers. \$\endgroup\$
    – Mike Scott
    May 23, 2017 at 11:09
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    \$\begingroup\$ @HagenvonEitzen On the 2017 computer still extant in 2050 that was referred to in the comment to which I was replying. \$\endgroup\$
    – Mike Scott
    May 23, 2017 at 12:53
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    \$\begingroup\$ Just a point about the terminology of the question; "film format" usually applies to the physical dimensions of the film and its packaging, not the photosensitive emulsion on the film, such as Kodachrome. For example, the most common film format when Kodachrome ceased production was "135" which is a long-ish strip of 35mm film with perforations that was rolled into a particular canister. Many types of emulsions are still available in 135 format. And Kodachrome was available on many different film formats. \$\endgroup\$ May 23, 2017 at 13:13

5 Answers 5


It is highly unlikely for a format to be lost in a way you describe. All the standard processes were thoroughly documented, and good documentation will keep for longer than unprocessed film.

But home processing of some materials - such as mentioned Kodachrome (K-14 process) - is extremely impractical. Because of the iconic status of the process it has been tried and found next to impossible.

The K-14 process is additive (dyes are formed in processing), and thus very different from both E-6 (the "usual" transparencies) or C-41 (color reversal film).

There was a reason why the K-14 process was never done in more than a handful labs worldwide, while the C-41 and E-6 at their height could be processed in corner drugstores and even today are doable at home using standard kit chemistry.

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    \$\begingroup\$ "it has been tried" - and that would seem to have been "in a fully equip professional photographic lab"! \$\endgroup\$
    – MrWhite
    May 22, 2017 at 19:40
  • \$\begingroup\$ Would there be any reversable way to selectively bind an opaque substance to individual color layers, such that one could bind something to exposed molecules on the red-sensitive layer, take a monochrome photograph of that, remove that substance (preferably while leaving the red exposure intact), bind something to the blue layer, photograph that, etc.? \$\endgroup\$
    – supercat
    May 22, 2017 at 21:16
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    \$\begingroup\$ @supercat that's an incredibly hypothetical question \$\endgroup\$
    – James T
    May 23, 2017 at 8:21
  • \$\begingroup\$ @JamesTrotter: I've seen a service that would develop K14 as black and white, but I don't know whether it irreversibly converted exposed chemicals to elemental silver (as in conventional black and white processing) or whether it bound something to the chemicals. If film doesn't need to be "viewable" as film that would seem to open up possibilities. \$\endgroup\$
    – supercat
    May 23, 2017 at 14:16
  • \$\begingroup\$ I like this answer, though I wouldn't call it next to impossible. Someone with the right combination of resources (time, money and knowledge) could certainly bring it back. It's a practical limitation more than a technical one. Also, there is a more recent instance of someone processing Kodachrome with... results. See: apug.org/forum/index.php?threads/kodachrome.136992/… \$\endgroup\$
    – bvy
    May 24, 2017 at 12:08

It is indeed true, that unknown masterpieces can be lost because they are only kept on an undeveloped roll of film, but not likely because it is impossible to develop the film. Exposures on undeveloped films tend to fade much faster than development processes disappearing, so the image is likely gone even if the process is still available. If you happen to find a 40 years old exposed C41-film, I would not expect to find any usable images on it, even if it is developed in the still more or less readily available C41-process.

Even if an outdated process is not commercially available anymore, you are very likely to find processing instructions somewhere. It has never been common for producers of photographic material to keep the processes a secret and the Kodachrome K-14 process is for example described in detail in US patent 3,658,525. Even if the process is known, it is of course not practicable to do K-14 development at home in the bathroom. You will not only need a seemingly endless list of odd chemicals (the synthesis of the more stranger substances is described in the patent), but you will also need a specialized apparatus for the additional exposure. So after you have obtained sodium hexametaphosphate, sodium bromide, 5-nitrobenzimidazole nitrate, potassium iodide, sodium sulfite, sodium sulfate, sodium hydroxide, sodium thiocyanate, hydroxylamine sulfate, 4-amino-N-ethyl-N-β-hydroxyethyl-3-methyl aniline sulfate, 1-hydroxy-N-(2-acetamidophenetyl-)2-naphtamide, hexylene glycol, polyoxyethylene, N-benzyl-p-aminophenol, methanol, p-aminophenol and some distilled water just to make the cyan developer agent (that is one of seven baths), before you develop for 4:30 minutes at 27°C, you will have to flash the film with red light from the back, while making sure, that the front of the film is kept dark.

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    \$\begingroup\$ What causes the film itself to fade? Is it background radiation slowly fogging it like xray exposure, the photosensitive material on the film itself being unstable and slowly decaying chemically, or something else? \$\endgroup\$ May 22, 2017 at 18:48
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    \$\begingroup\$ @DanNeely - that right there is the makings of a an excellent new question! \$\endgroup\$
    – FreeMan
    May 22, 2017 at 19:54
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    \$\begingroup\$ Recognize some of these chemicals from my 10 years working at a 1-hour photo-shop and developing C41-film, and some of the others should be possible to get at a chemists... But yeah, the need to expose the film repeatedly would be a major drag. \$\endgroup\$ May 22, 2017 at 23:27
  • \$\begingroup\$ If you don't mind a follow-up... Is it the case that colour formats can involve complicated chemistry, but B&W processing is always relatively simple? Or can even B&W processing sometimes be as arcane as what you've described? \$\endgroup\$
    – Ned B
    May 23, 2017 at 7:49
  • \$\begingroup\$ @NedB B&W films have only a single "color" layer, with the image conveniently formed by metallic silver (except for chromogenic B&W, such as Ilford XP2). Colour films have at least three layers. So as a rule colour processing is more complicated. Not that B&W would be above using fancy chemistry - look at collodion users, who routinely work with cadmium salts at their homes :) \$\endgroup\$ May 23, 2017 at 8:32

But would it be possible, in principle, for a film format to be so thoroughly lost to history that you couldn't get any image out of the negatives whatsoever?

In principle, once the process is still known and documented fully somewhere, then someone could (in principle !) carry out that process assuming they're bloody-minded enough to see it through.

Even with most of a process, but not all, documented someone could in principle work out the missing steps and do it.

But beyond some threshold, the practicalities mean that once you don't have enough of the process documented to work out the full process, then that process is effectively gone for good.

The more elaborate or delicate the process, the less likely it is to survive commercially and the less attractive it is to try by hand.


Over the years, many film developing processes have come and gone. Under normal circumstances it would be impractical, but not impossible resuscitate these vintage processes. Using the same logic, will devices be available 100 years from now that will read, and display as well as print, our current digital media? I have a shoebox filled with 8 track music, if I lend you a few cassettes, can you play them?

Kodachrome can be developed as a black & white negative and someone has figured out how to develop to obtain colored slides. Sorry to report that the images obtained are only a shadow of this film's former glory.

Kodachrome is particularly difficult because this film needs three specialized color developers to cause it to develop and blossom to reveal magnificent color images. These are:

Kodak coupler C-16, (N-[o-acetamido phenethyl]-1-hydroxy-2-napthamide) (cyan)

Kodak coupler M-32, (1-phenyl-3-[3,4-dichlorobenamido]-5-pyrazolone) (Magenta)

Kodak coupler Y-54, (Alpha-benzoyl-o-methoxy acetanilide (Yellow)

These are now in the public domain, you can make them yourself. The rest of the processing chemicals are ordinary and customary to photo processing.


Almost all photographic films use the same basic proces - silver halide grains exposed to light are then developed in and aqueous alkaline solution containing developing agents that reduce the exposed silver salts to metallic siver, so the answer to the original question - "Do defunct films formats really mean the pictures can never be seen? " is no, its almost always possible to devlop some sort of image from films even if the original process is now defunct. Kodachrome of the K-14 process type (Kodachrome 40 and Kodachrome 25 for instance) can be processed as black and white negative or black and white reversal - I've done both with good results, including a cartridge of Super 8 film that sat in a camera for 18 years and wasn't stored in cool conditions. The oldest Kodachrome I've sucessfully reversal processed expired in 1968.

Black and white film is remarkably resilient (and colour film consists of 3 layers of B&W emulsion).

Its not impossible to hand process Kodachrome in colour either, if you read the Richard Bent / Rowland Mowrey patent its obvious that that the inventors actually developed the entire process using hand methods in a lab. The only major obstacle is the difficulty obtaining the couplers, and maybe CD-6 developer (used for the yellow developer, the rest of the chemicals are more readily available. However, there are alternative couplers commercially available, so obtaining a colour image formed by dyes is possible (I did it last week with 16mm K40 movie film), obtaining the wonderful results of the original K-Lab processing with the incorrect couplers * * not be possible.

  • \$\begingroup\$ The longevity of properly-processed Kodachrome is, alas, going to be hard to duplicate unless a person uses the exact correct process. Perhaps one day it will come back. \$\endgroup\$ Aug 23, 2018 at 20:09

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