Expired color film?

[Sirius Glass]

You crack yourself up.

So you understood it?

 

[mtjade2007]

These are two separate issues, though.
Processing C41 film at home to a decent quality level isn't very difficult. Many people do so, successfully. It doesn't take a Jobo ATL or similar, either.
The results with fresh film will generally be better than with expired film. There's no clear reason to associate fresh film with poor quality home processing and expired film with good processing. The only reason appears to be, is to somehow make expired film look more attractive than it really is. There's no point in doing this. Just tell a straight story to OP and let them decide.

Home processing C-41 is not difficult. This is true. But don't assume every DIYers can do it by following what should be followed precisely and consistently. Otherwise this forum would not have had so many questions asked by DIYers about processing failures. Chemical mixing alone could be very problematic. For example, trying to mix 500 ml working solution out of the concentrate of a 10 gallon kit. The accuracy of mixing, developer deterioration over time, film and film tank prewarm, development temperature stability, etc. are variables that any one of them could easily go wrong and cause processing failure.

JOBO ATL is not failure proof at all. The learning curve is significant and a bit technical and not covered by Kodak docs at all. An experienced operator could program a run to process a particular batch of films perfectly but this is not trivial for a beginner at all. Things could go wrong when a users gets into cost saving , such as reusing, replenishing, mixing partially out of a larger kit, chemical storage, etc. Yes, C-41 by an ATL machine should be easier but I can assure you it is not failur proof and the failure rate can be very high.

I started out with fresh films as a beginner and easily succeeded initially. But I have to admit I ran into all sorts of failure over time. Just imagine how a teenage beginner driver gets into trouble down the road before transforming into a mature driver.

 

[Sirius Glass]

Home processing C-41 is not difficult. This is true. But don't assume every DIYers can do it by following what should be followed precisely and consistently. Otherwise this forum would not have had so many questions asked by DIYers about processing failures. Chemical mixing alone could be very problematic. For example, trying to mix 500 ml working solution out of the concentrate of a 10 gallon kit. The accuracy of mixing, developer deterioration over time, film and film tank prewarm, development temperature stability, etc. are variables that any one of them could easily go wrong and cause processing failure.

JOBO ATL is not failure proof at all. The learning curve is significant and a bit technical and not covered by Kodak docs at all. An experienced operator could program a run to process a particular batch of films perfectly but this is not trivial for a beginner at all. Things could go wrong when a users gets into cost saving , such as reusing, replenishing, mixing partially out of a larger kit, chemical storage, etc. Yes, C-41 by an ATL machine should be easier but I can assure you it is not failur proof and the failure rate can be very high.

I started out with fresh films as a beginner and easily succeeded initially. But I have to admit I ran into all sorts of failure over time. Just imagine how a teenage beginner driver gets into trouble down the road before transforming into a mature driver.

I had not problems at all from the start with the Jobo CPP2 processor other than getting the film on the reel. Using the Jobo 3010 Expert Drum is a pleasure and problem free for 4"x5" sheet film, well worth the expense.

 

[koraks]

Home processing C-41 is not difficult. This is true. But don't assume every DIYers can do it by following what should be followed precisely and consistently

Be that as it may, the issur will still be the same with expired or fresh film. The only difference is that with expired film, you're never quite sure if the results are wonky (or creative, YMMV) due to processing problems or due to the film itself.

Btw, doing C41 in a Paterson tank with a water bath and a sous vide cooker is just as easy or difficult as with a Jobo. Just a whole lot cheaper. The savings can be used to buy fresh film

 

[mtjade2007]

Be that as it may, the issur will still be the same with expired or fresh film. The only difference is that with expired film, you're never quite sure if the results are wonky (or creative, YMMV) due to processing problems or due to the film itself.

Btw, doing C41 in a Paterson tank with a water bath and a sous vide cooker is just as easy or difficult as with a Jobo. Just a whole lot cheaper. The savings can be used to buy fresh film

My experience with expired films is if processed properly I did get very good results. This includes Kodak UC, VC and NC. I have done quite some expired Fuji NPS and Konica Centuria when I did it right. The words did it right is not as simple as it looks. It will happen when I used strictly fresh chemicals, temper the juice accurately and did it one shot. Once I started to get into replenishing, reusing or if the developer wasn't fresh then even fresh films got crossover fault witnessed by the difficulty in scanning. Film and drum/tank prewarn was also a big deal to me especially if I process multiple rolls such as 2 220 rolls at a time. Again, yes C-41 is easy. I knew very well about that. But think about why a teenager driver gets into trouble once he or she gets more miles on the odometer.

Time is expensive too. I am now used to press the start button on my ATL-2300 and walk away. I then pick up the film 30 minutes later. I do use fresh films when I get into important shoots. The only problem now is there is not a whole lot of selections available any more. By the way, I occasionally bought expired films but all from large stores. Freestyle in LA was one I bought expired film from. There were quite a few large film distributors in LA. I believe Freestyle got freshly expired films from those distributors cheap then sell from their store in retail. So their expired films were pretty good. My main source of expired films is from my own freezer. I over bought films from time to time. Maybe this is why I don't really have much problems with them.

 

[mtjade2007]

Be that as it may, the issur will still be the same with expired or fresh film. The only difference is that with expired film, you're never quite sure if the results are wonky (or creative, YMMV) due to processing problems or due to the film itself.

Btw, doing C41 in a Paterson tank with a water bath and a sous vide cooker is just as easy or difficult as with a Jobo. Just a whole lot cheaper. The savings can be used to buy fresh film

I agree completely. But keep in mind, depending on the storage condition not all expired films are junk. By saying expired films are inferior is not a proper implication. I recently gave a few expired Konica VX-100 rolls to a friend. He just emailed me asking if I have more to give. He told me he had received scans back from a lab and apparently he is very happy with it.

 

[koraks]

My experience with expired films is if processed properly I did get very good results.

I know. You said that before. I said before that my experience is different.

Once I started to get into replenishing, reusing or if the developer wasn't fresh

So lesson learned. My experiences with fresh, one-shot developer are good; you know what you get. It's not very difficult. It's just doing the same simple process the same way every time you do it. Things usually get difficult if you experiment and run into unforeseen problems. I know, because I experiment a lot, so I've run into many, many problems. Such problems generally stay away if your process is consistent. Which, again, isn't difficult. It's just a little tedious.

witnessed by the difficulty in scanning.

I'm very skeptical about using scanning as a quality check for color processing unless a calibrated scanning setup is used. Few amateurs use such a setup. Most people in fact scan with considerable automation in the scanning software enabled, which 'fixes' the colors - and totally throws off whatever original color balance there was.

The issues I've had with expired film manifested with darkroom printing, which contrary to scanning, is always pretty much the same as long as you don't touch the filter knobs. The slightest deviation in processing becomes visible (it's not always a problem - although with expired film, it mostly is).

Time is expensive too.

We all have different priorities and make different calls. I like the quick turnaround of home-processed film, but don't want to invest in a big Jobo like the ATL, which takes up space I don't want to sacrifice to it and that brings an eternal maintenance and repairs concern with it. They don't live forever, these big hulks. I gladly sacrifice the bit of time I spend on the manual operations of film development - only some of which are taken away by using an ATL, by the way. Mixing chemistry, filling up tanks (for the machine or to put into a water jacket), cleaning equipment, loading film, unloading and cutting film, archiving etc - they're all operations that are necessary whether you use a machine or not. In the end, what's saved is indeed up to half an hour for a roll, if that. For you, that may be worth it. For me, it isn't.

By saying expired films are inferior is not a proper implication.

On average, expired films are inferior to fresh films. I stand firm by that qualification. It's very nice your experience tilts the average a bit into a favorable direction.

He told me he had received scans back from a lab and apparently he is very happy with it.

There are many examples of people being happy with technically inferior results. I think about 80% (conservative estimate) of contemporary analog photography fits into that category. There's nothing wrong with it, but it doesn't change anything about the technical quality level.

 

[mtjade2007]

Here are two example of scans from expired (more than 20 years) Konica VX-100, These are my own images not from the friend. I am not an expert in scanning. These are unadjusted scans.

 

[mtjade2007]

It's commonly agreed that bad expired films will be grainy and foggy. I don't see that in my two images here. Does that tell the film despite being long expired is still decent? These were from about a month ago.

 

[koraks]

Does that tell the film despite being long expired is still decent?

No. It's impossible to judge on the basis of these images how well the film has fared since it expired. Try something with skin-tones or a more expanded color palette. Your flowers are pretty, but also form subject matter that is deceptive in the sense that things must be horribly wrong before colorful things like flowers start looking problematic. This is different with subject matter that we more easily recognize as accurate - skin tones, neutral greys, gradients from grey to white (e.g. cloud formations in daylight) etc.

For instance, the roses look nice and red, but is that the actual same red hue they had in reality? I'm virtually certain this is not the case, but I can't be sure since an absolute reference is lacking. However, if the red isn't accurate, try to fix it and the green will go wonky.
Interestingly, the roses are deeply saturated, while the other shot shows very muted colors. Part of this is due to lighting differences, but these don't explain everything - e.g. the yellows and violets in that particular flower at that stage of bloom tend to be more saturated. This suggests that in scanning, between these frames considerable differences exist. As a result, it's unclear what we're really looking at when we're judging color - the aptness of the scanning software in adjusting the colors, or some quality of the film? In case the latter, how come it's giving very high chroma results in one case and lower chroma output in another?

So no, this doesn't prove much, except maybe that flowers are pretty and you're evidently pleased with how they turned out. That's OK, but that's not a solid absolute benchmark to judge the performance of a photographic medium on.

It's commonly agreed that bad expired films will be grainy and foggy.

Foggy, yes. A grainy look is a consequence of printing or scanning through that additional density. However, the real problem is crossover. To an extent, this can be compensated for even by the scanning software itself, so film that has definitely gone wonky may still look (sort of) fine on your scans. It'll be impossible to print well optically. Moreover, differences tend to become painfully clear as soon as you compare expired film side by side under the same conditions with fresh film.
PS: I've said it before, but I've shot hundreds of rolls of expired Superia 200 and C200 that were quite badly age-fogged (stored refrigerated entire lifetime), but had not crossed over very badly. On the other hand, I've also shot many rolls of Portra 160 and 400 that were far less expired, far less foggy, but problematically crossed over. I might have photographed some pretty flowers with it and indeed, stuff like deep blue skies shot with a polarizer filter seemed to come out fine, but the rest of the colors in the same scene would be seriously compromised. Just to illustrate that fog and crossover are different things, although in expired color film, they tend to occur together and are indeed somewhat related.

 

[lamerko]

Something funny. Yesterday I found two exposed rolls in the fridge - from a few months ago. I had tested a slightly dated 50D and 500T (I had bought some short-end, with the seller claiming they were from 2018, no guarantee of how they were stored. 50D turned out to be manufactured in 2017 according to the marking). I developed the two rolls together using the standard procedure, only with a slightly increased development time. I take out the spindle and... one is black! I said, apparently someone looked at what was in the box before sending it. The second (50D) turned out to be good, but slightly scratched with some adhesives. Anyway, I had taken them for various tests, with almost no money. I had decided to throw away the developed 500T, but in the light I noticed that it was actually a massive fog - the captured footage was only slightly visible. In the end it turned out to be my mistake - I had mixed up the film boxes. Instead of the newer Vision3, I was taken from the old EXR 5296, which is approximately 30 years old. Unfortunately, the marking is not visible and it is not clear when it was manufactured, but I have an EXR 100T that is a respectable 30 years old - manufactured in 1993. Besides the massive fog, I had shot it at 320 ASA, which in this case was...too optimistic. I still decided to run it on the scanner - as it was without a final wash, with garbage (I had separated it for disposal). As a matter of fact, the scanner was able to pick up SOMETHING, even though the naked eye sees almost nothing on the film. I'll play with it. I wonder what I could squeeze out of it

 

[faberryman]

What were you testing with expired 50D and 500T?

 

[lamerko]

A few months ago I had gone for a walk when snowdrops and crocuses were in bloom in the forest. The light wasn't good - there was some sun peeking through the trees, but overall it was pretty dark, and my lens had a maximum aperture of 3.5. Focusing was a struggle, and the too-narrow DOF made it even more difficult. In general, the focus is not aimed at half the frames
Otherwise, I took these films for experiments with the chemistry that I mess up myself, as well as various attempts (reverse the film like a slide, etc.) without costing me much. I got these pieces about 200ft each for 30 euros or so

 

[mtjade2007]

Thank you Korak, for your in-depth input of this subject matter. I am not able to post any pics with people in them due to privacy issues. As far as skin tone goes in the digital approach there can be a huge room for tools such as Photoshop to tweak. There isn't a standard skin tone for reference either and everyone can be completely subjective. I usually don't judge an image only looking at the skin tones.

Don't over estimate how smart a film scanner or Photoshop is. There is no way a film scanner knows how a film's crossover error is and correct it properly. I don't believe a darkroom expert can tweak the dichroic filters to correct a film's crossover error either. I maybe wrong about Photoshop. I use a very old one and I only use it basically for adjusting density and contrast. I could use it to enhance or reduce saturation. But it can not correct crossover faults of images. I don't know if the latest Photoshop is much more magical or not.

I sometimes hate my film scanner because it will spit out bad scans if my film is too over or under exposed. It definitely will spit out crossover faults if a film is improperly processed and it is just impossible to make a decent correction. But it will produce beautiful scans if it is fed with fresh and expired films that are still decent provided they are all properly processed. You can easily see that by looking for crossover faults in the scan. Whenever I see crossover faults I basically give them up and do not attempt to color balance them because it simply will not succeed.

Expired films can be very decent despite the fact they will shift away from their original characteristics over time. That is not necessarily a bad thing. Just treat them as different films. When they reach a point that color crossover is significant enough or fog and grain are impacting the final images then pronounce them bad and toss them. If a photo shoot is work related then don't use them. Use fresh films and make sure to use a lab that can be trusted.

 

[mtjade2007]

I had not problems at all from the start with the Jobo CPP2 processor other than getting the film on the reel. Using the Jobo 3010 Expert Drum is a pleasure and problem free for 4"x5" sheet film, well worth the expense.

Most of my problems with my ATL machine was related to the quantity of film processed. I tend to over estimate the capacity of the developer and made the mistake of using less amount of juice required to process the amount of film I processed. Also prewarm multiple rolls of film and the drum was under looked. Foolish me. It took me a long time to get this right. I once processed a one foot stripe of film and when I saw how perfect it came out I finally woke up. The lesson: don't try to save. The developer is cheap and the prewarm is free.

 

[MattKing]

As far as skin tone goes in the digital approach there can be a huge room for tools such as Photoshop to tweak. There isn't a standard skin tone for reference either and everyone can be completely subjective. I usually don't judge an image only looking at the skin tones.

While this is correct, it is also true that many humans are particularly attuned to colour problems with skin tones.
And that seems to apply to a reasonably wide range of complexions and skin colours.
I have a feeling there is some evolutionary factors behind this.

 

[jeffreyg]

I was curious so I read these threads. I very rarely use color film and never processed any but recently ran across some old family photos that had faded with terrible colors as well. I don’t know who took them or anything else about them. I decided to scan them and converted them to black and white. Then made pretty decent corrections in Photoshop Colorized them with Photoshop nural filter and got surprisingly good results on most. I have no idea how it works but it could be worth a try if you don’t want to toss some of the film and like to experiment.

 

[koraks]

Don't over estimate how smart a film scanner or Photoshop is.

I don't. But I see a lot of scanners and software burp out results that look sort of OK from film that is decidedly not OK anymore. The color problems that do exist often go unnoticed by the users ("hey, the roses look pretty and red and aunt Edna's dress is green, all good!") or are simply accepted/embraced because it's the 'vintage film look'.

I don't believe a darkroom expert can tweak the dichroic filters to correct a film's crossover error either.

To an extent, but that's a different story. I think you and I agree that when there's crossover, it's a challenge that needs to be overcome if you're looking for natural color reproduction, and at that point, it's really frustrating to realize that the crossover results from the choice of using expired film while fresh film was available. It's fine of course if you want that 'vintage' look; in that case, expired film can be the surprise you're looking for. For the same reason we used to cross-process E6 and C41 back in the 1990s and early 2000s. I tried it back then, and never quite got the hang of it. For some reason, I found my slides (mostly did E6 in C41 processing) just horribly ugly. I guess others found their results 'creative' ('vintage' wasn't a fad back then; I think we mostly drew on a pop art-inspired rationale for this kind of experimentation).

 

[mtjade2007]

I don't. But I see a lot of scanners and software burp out results that look sort of OK from film that is decidedly not OK anymore. The color problems that do exist often go unnoticed by the users ("hey, the roses look pretty and red and aunt Edna's dress is green, all good!") or are simply accepted/embraced because it's the 'vintage film look'.

Your undersatnding of scanners is a reasonable one. But my experience with them, after scanning more than a couple foot pile of Print File pages of negatives, is different. There is definitely no AI involved in scanner hardware/software. They are really dummy devices. Think about it. They have to deal with all kinds of negatives each with possibly drastic different characteristics. The best they could possibly have is a set of ICC profiles each to deal with one brand/type of film but I doubt they do. They also have to deal with over and under exposure, various color temperature (morning, noon time and evening). I don't think they will do anything about color crossover faults. Judging from the byte size of my film scanner software of 6.7 mega bytes It is a dummy, not one that contains any tricky software burp. The reason they are not cheap is because they are precision optical machines. It would be the Photoshop or the like that may be magical in post processing of scanner output.

To an extent, but that's a different story. I think you and I agree that when there's crossover, it's a challenge that needs to be overcome if you're looking for natural color reproduction, and at that point, it's really frustrating to realize that the crossover results from the choice of using expired film while fresh film was available. It's fine of course if you want that 'vintage' look; in that case, expired film can be the surprise you're looking for. For the same reason we used to cross-process E6 and C41 back in the 1990s and early 2000s. I tried it back then, and never quite got the hang of it. For some reason, I found my slides (mostly did E6 in C41 processing) just horribly ugly. I guess others found their results 'creative' ('vintage' wasn't a fad back then; I think we mostly drew on a pop art-inspired rationale for this kind of experimentation).

Processing error creates crossover error, same does deteriorated expired films. But expired films don't fall off the cliff on the day of their expiration date. If kept in freezer they actually will last a very long time. I bought expired films mainly from FreeStyle in Los Angeles. Their expired films probably came from film/darkroon supply distributors in the area. The films were decent and the cost were much less. It's a good business for them so why not. The largest film/darkroom supply distributor in Los Angels back then was a Korean owned business. I am sure the name is still remembered but I don't. If Freestyle sourced their expired films from there they were definitely decent. I never heard anyone saying cold store special at Freestyle was bad.

Tweaking dichroic filters of a colorhead is really similar to what people do in Photoshop, except Photoshop might be able to do things beyond traditional wet darkroom people will accept. My experience with Photoshp is it is not able to correct color crossover of a scanner output. I might be wrong since my Photoshop is more than 20 years old. If the film is good and the processing is right the scanner will spit out a file that needs very little tweaking in Photoshop. That's what my experience with film scanner is.

It's a real pleasure discussing the subject matter with you, Korak. Thanks a lot.

 

[koraks]

But my experience with them, after scanning more than a couple foot pile of Print File pages of negatives

I can relate; I presently own two scanners, a 4990 and an equally old Scan Dual IV. Combined, they have processed many thousands of frames of 35mm up to 8x10" of B&W, C41, ECN2 and E6 - not to mention prints (the flatbed). So that's what I mostly base my comments on, plus a dash of some (mostly) amateur-level software and electronical engineering experience. Both my scanners especially in color negative mode will apply dramatic color adjustments that appear to be very non-linear. I never attempted to reverse engineer the algorithms involved, but they are there and exceed an invert-and-apply-default-linear-curve-adjustment.

Here's something you might try with any of your scanners: scan some color negatives (ECN2 or C41, doesn't matter) using the color negative setting in your preferred scanning software. Now scan the same frames using the slide/color positive setting. Attempt to adjust the positive scan to obtain the same result as the color negative scan you've just made. Note if the adjustment curves you need to apply involve only linear adjustments, and if the separate color curves need to cross over in order to obtain the same result. If you want to go further, try the same thing with a different film type - for instance do a scan with fresh Kodak film and one with very expired Konica film. Perform the same routine, and note if the exact same curve adjustments will give the results you produce by doing an 'automated' negative scan.

This gives you an impression of what's approximately going on 'under the hood' of your scanner. I suspect the results may surprise you as to how smart your apparently dumb scanner actually is.

Tweaking dichroic filters of a colorhead is really similar to what people do in Photoshop, except Photoshop might be able to do things beyond traditional wet darkroom people will accept. My experience with Photoshp is it is not able to correct color crossover of a scanner output. I might be wrong since my Photoshop is more than 20 years old.

The basic curve adjustment functionality of Photoshop, which to the best of my knowledge has not changed in the past two decades, is far more powerful than what you can do with just a dichroic head. Certain adjustments that take a few clicks in a few seconds in PS take hours or days of work with masking and many test prints. Sometimes you can luck out in the darkroom and get close by relatively simple things such as a little burning and dodging, or a color-adjusted pre- or post-flash exposure. But overall, the possibilities for corrections with just the most basic curves dialog n Photoshop are far more powerful and convenient than what's technically possible with an enlarger.

If the film is good and the processing is right the scanner will spit out a file that needs very little tweaking in Photoshop. That's what my experience with film scanner is.

Now figure what it takes for a scanner to do that regardless of what brand or age color negative film you feed it - just place two different brands and vintages color negative strips side by side and notice the difference in orange mask hue and density. Your scanner automatically corrects for this - and that's a lot more involved than it might seem at first glance, as it requires an adjustment of three separate curves and involves adjusting at least one point as well as the slope of each individual curve (and possibly also the curve shape as well as the start + end point).

It's a real pleasure discussing the subject matter with you, Korak. Thanks a lot.

Much appreciated, likewise!

 

[BrianShaw]

While this is correct, it is also true that many humans are particularly attuned to colour problems with skin tones.
And that seems to apply to a reasonably wide range of complexions and skin colours.
I have a feeling there is some evolutionary factors behind this.

“this” being correct - no standard, I assume or am I incorrect? So who was Shirley? LOL

The problems I’ve experienced with bad rendition of skin color often seems to be the separation between photographer and print finisher. The former can see reality while the latter has to guess and assume.

{Moderator's Edit: I tried to replace the Media link with a web address and image, because the "Cookies" approval box was driving me crazy - but had no success!}

 

[Prest_400]

PS: I've said it before, but I've shot hundreds of rolls of expired Superia 200 and C200 that were quite badly age-fogged (stored refrigerated entire lifetime), but had not crossed over very badly. On the other hand, I've also shot many rolls of Portra 160 and 400 that were far less expired, far less foggy, but problematically crossed over.

This is interesting. As my colour shooting is done in batches and pulses (given the logistics that I send out and have them lab processed) I have always frozen the unexposed film as well as refrigerating the exposed rolls waiting to be sent out.
Another factor has been discontinuations, increasing prices and availability.

Film that I bought fresh and just froze, I have Fuji 160NS 220 exp 2018, Provia exp 2020 and Portra 400 expired 2021. The Portra is fine but I am eyeing if it starts to exhibit some signs of age together with a couple of Xray passes on top of cosmic rays. But scanners are hiding this.

My best success was some 2006 Fuji Astia in both 135 and 120 and slide looked very good, without crossovers or fogging!

I don't. But I see a lot of scanners and software burp out results that look sort of OK from film that is decidedly not OK anymore. The color problems that do exist often go unnoticed by the users ("hey, the roses look pretty and red and aunt Edna's dress is green, all good!") or are simply accepted/embraced because it's the 'vintage film look'.

And that's a good point, it's even desirable by some photographers. I'm not really bothering with others' expired film because of the unpredictable results and from what I see the asking prices for old film are like for fresh films.

 

[MattKing]

“this” being correct - no standard, I assume or am I incorrect? So who was Shirley? LOL





The problems I’ve experienced with bad rendition of skin color often seems to be the separation between photographer and print finisher. The former can see reality while the latter has to guess and assume.

The legend is that "Shirley" was the name of one of the first Eastman Kodak employees that served as a model for these calibration standards.
When I worked as a colour printer, our customers were all professional photographers, and most of my work was wedding or portrait photography, with a smaller amount of commercial photography as well.
Many of our customers photographed weddings for members of the Chinese community in the area - many of whom were multi-generational, with the older generation having immigrated from Hong Kong (mainly) and the younger generation having been born in Canada.
Our customers - the photographers - frequently had to deal with an interesting sociological issue. Their older generation Chinese Canadian customers tended to prefer prints with skin tones that were more "Caucasian" and their younger, born in Canada Chinese Canadian customers tended to be happier with prints with skin tones that were more (Hong Kong) "Chinese". No doubt those preferences reflected the differing experiences of the different generations.
From time to time we redid prints that adjusted those skin tones to match one of those two preferences.
The various "Shirley" negatives and prints reflected the customer bases of the labs that used them - they differed around the world.
They no doubt lagged behind societal changes, even though over time they did respond to those changes.
FWIW, due to the distribution of the population in our area when I worked as a colour printer, I was much more attuned to "Caucasian" and (Hong Kong) "Chinese" skin tones, but I did have some experience and familiarity with skin tones from people with roots in the Punjab region of the Indian sub-content, so could work well with those.
I'm not sure how well I would have done back then with "Black" skin tones - the population around here was tiny at the time.
In any event, I'm much more able to pick up a colour cast on a skin tone than just about any other subject.
The other thing that I always find funny about references to "Shirley"s is that my mother's name was Shirley. In a youthful world where matters photographic were almost omnipresent, it always made me smile.

 

[BrianShaw]

You make a good point… in some communities especially, self-perception of skin color and desired rendition of skin color in photographs can be very different from either others perception or reality. That makes the challenge very challenging. If the challenge were only color cast it would be a lot easier.

I’m not sure what this has to do with expired film, though.

 

[MattKing]

I’m not sure what this has to do with expired film, though.

It relates to the "?" at the end of the thread title .
It is the "how can you reliably tell?" part of the issue.