Higher silver content.

[schyter]

Hello everyone ...

A higher silver content in the films (such as those of the 50s / 60s), made them qualitatively better?
What peculiar characteristics were due to more silver, compared to thin modern ones?

Many thanks.

 

[Vaughn]

No, I believe the differences are more subjective. Too many other factors, as companies looked for ways to reduce silver but increase desired qualities.

I read an interesting article decades ago that compared max black of photo papers and their silver content. No correlation.

 

[xkaes]

Check out Dr. Richard Henry's book, "Controls in Black and White Photography" where he examines the common belief in photography that more silver in photo paper produces blacker blacks. It doesn't -- so it won't in film either.

And more silver won't produce finer grain either. That depends on the size of the silver crystals.

There are a lot of beliefs in photography that are pure myth. Henry's book explores many of them, but there are still plenty of them left to go around. The point of his book is that you should run some simple tests yourself before accepting anything as photographic "gospel" -- even if it make superficial sense, such as more silver means blacker blacks.

 

[koraks]

And more silver won't produce finer grain either. That depends on the size of the silver crystals.

And their shape. Tabular grain comes to mind. Which BTW is also a very smart way of getting very good density without using much silver.

the common belief in photography that more silver in photo paper produces blacker blacks.

Which is all the more silly if you realize that the black parts of the print are in fact the thin parts in the negative, so those parts where only little silver remains after processing.
Also, it's surprising how little silver you actually need to produce very high density.

 

[faberryman]

Is there any historic and/or contemporary data as to the silver content of various films by which we can evaluate claims of "higher silver content"?

 

[Christiaan Phleger]

Hmm well you may not recall that the whole T-grain shift was in search of a lower silver content emulsions following the inflated silver market run by two brothers (look it up), but yes it was very good the concept of doing as much with less by managing the shape of the silver crystals. In general, the overall gains in emulsion control by the understanding and inclusion of T-grains also improved standard emulsions. As I've understood it. And in practical use in my case.

 

[xkaes]

Is there any historic and/or contemporary data as to the silver content of various films by which we can evaluate claims of "higher silver content"?

Since silver content is not relevant to anything, what would you gain from knowing this? If you want to repeat Henry's tests, just read his book. It tells you exactly how he did it -- that would be some historic data.

 

[BHuij]

A decade or so ago when I worked at a camera store, we had a guy come in all the time to develop fairly high volumes of 120 film. He was a great dude and a good photographer to boot, and always down for a chat about old cameras and whatnot. But the guy would not shut up about Polaroid type 55 film, and swore that the extra silver content gave it a look that no modern film could recreate. I personally have a hard time seeing the difference. *shrug* chalk it up to analog photographers being prone to ephemera.

 

[cullah]

Years ago I worked in a camera store. We were still selling/using Agfa Portriga Rapid paper. I noticed there were no expiration dates on the package. Kodak, et al, did have expiration dates. When I asked my boss why the Agfa didn't he told me it was because the Agfa had so much silver in the emulsion it was in no need of use by dates. Fast forward 45 years. I was exploring the local junk shop and came upon a beat up box of PORTRIGA RAPID. The box, though still light tight, was in pretty bad shape. I took it home and in my darkroom found there were about 10 sheets of paper. When I made a print with one of the sheets. I was astonished to find white highlights and the best black I have ever seen in photo paper. Go figure!

 

[BHuij]

That is absolutely fascinating. I would think that more silver in the emulsion would increase the chances of accidental oxidation (and presumably that would cause fogging?), rather than decreasing it.

 

[MattKing]

While I'm sure that reduced use of silver was a business advantage of the T-Max films, the quality improvements came from being able to make smaller, flatter silver grains (with less silver in them) respond as well or better to light.
Silver in so called "silver rich" emulsions tends to get in the way of itself, and just ends up being wasted.
In particular, films like the Vision series of motion picture films and the T-Max (and Delta, and Acros) black and white films are capable of much higher acutance than their forerunners - and thus are capable of higher sharpness.
Some of the historical attachment to the older "silver rich" emulsions ignores the fact that a lot of people's experience with those emulsions involved larger film formats.
A few people miss the older emulsions because they responded more to expansion and contraction development controls.
And as for older papers being longer lasting, that may very well be due to a combination of the banning of certain constituent agreements like cadmium and the fact that modern papers include trace amounts of chemicals designed to adjust them for contrast and speed consistency, batch to batch. Those trace chemicals sometimes affect longevity. Older papers had a tendency to vary between batches.
And "best before" dating is a function of both inventory control and the maintenance of ISO certification, and only tangentially a function of inherent longevity.

 

[xkaes]

If B&W film or paper are stored correctly, they last a LONG time.

 

[flavio81]

Hello everyone ...

A higher silver content in the films (such as those of the 50s / 60s), made them qualitatively better?
What peculiar characteristics were due to more silver, compared to thin modern ones?

Many thanks.

Search "Photo Engineer" (Ron Mowrey) posts on the subject.

 

[Vaughn]

A decade or so ago when I worked at a camera store, we had a guy come in all the time to develop fairly high volumes of 120 film. He was a great dude and a good photographer to boot, and always down for a chat about old cameras and whatnot. But the guy would not shut up about Polaroid type 55 film, and swore that the extra silver content gave it a look that no modern film could recreate. I personally have a hard time seeing the difference. *shrug* chalk it up to analog photographers being prone to ephemera.

The film for the Type 55 was supposively Panatomix-X, or at least until Kodak got sued by Polaroid for copyright infringment. Right after this I got several boxes of experimental Type 55 that no longer used Kodak's film. Seemed to work just fine, too. But the original film for the Type 55 was very sweet...good contrast in most conditions and a 'creaminess' in the tonality could be achieved. Mark Klett's work demonstrates this well.

 

[Don_ih]

Older b&w papers fared better the higher the contrast grade. If you find a box of 50-year-old grade 5 paper, it's probably pretty good. But 50-year-old grade 1 paper? Almost guaranteed to be useless.
Most Portriga Rapid I've handled lately is too age fogged to be useful.
As for silver content, ask Adox. They advertise a film as having the highest silver content and greatest range of tonality, don't they?

 

[laser]

I managed the design and manufacturing of T-MAX Films and also the film in POLAROID Type 55.

I read through the posts above and offer these comments:


The patent conflicts between Kodak and Polaroid had no influence on the business and technical discussions regarding Type 55. The instant issues were never mentioned to me by Kodak or Polaroid.

From 1981 (when I was made responsible for the Polaroid contract, a few percent of my job) until it was discontinued little change was made in the film Kodak made for Type 55. Polaroid may have looked at film from other sources but the demand was "smooth". We produced on a rolling horizon with slight adjustment to volume as required. The film may have started as a derivative of Panatomic-X in the distant past. There was little similarity between Pan-X and the Type 55 film in 1981 and later.

Silver-rich emulsions provide little value compared to modern emulsions technology.

The primary benefits of T-grains is reduced graininess at a given speed plus increased surface area to absorb chemicals. The disadvantages are physical sensitivity, developability, dye retention, spectral sensitivity, sensitivity during growth and finish etc.

Manufacturers may use improved technology that requires less silver. I was involved in silver reduction programs starting in 1978 on x-ray films. At Kodak were we never allowed to reduce product performance to achieve silver reduction. This required technology improvements that created silver grains with greater covering power and increase surface area. What counts is the resulting image not the amount of silver salt you drop in the emulsion-make kettle. Like taxes it isn't how much you make that counts, it is as how much you keep after taxes.

Silver coverage doesn't correlate with keeping-properties (long life).

Long-life is created by having stable materials in the emulsion: sensitizers etc. It is also helped by scavengers that neutralize materials that can damage the sensitometry. Long-life is designed and then confirmed by accelerated (hot and humid, 100F 85%) keeping tests. Kodak tried to sell only products that we stable under the recommended keeping conditions. Our horizon was 1 year after the "use by date" when kept under the recommended conditions. We paid NO attention to below-zero conditions or times greatly exceeding the use by date. The reason is that we didn't have the ability to predict more than a year beyond the use by date. 100F at a few weeks predicted a few years. 120F+ influenced emulsions in such a way that they were not predictive. Real-time keeping (testing 5-year old film that was kept as recommended) is of little value. After 5-years the formulation and the raw materials have changed so the data is of little value.

I hope this is useful.

Bob Shanebrook

www.makingKODAKfilm.com

 

[laser]

www.makingKODAKfilm.com

 

[cmacd123]

The primary benefits of T-grains is reduced graininess at a given speed plus increased surface area to absorb chemicals. The disadvantages are physical sensitivity, developability, dye retention, spectral sensitivity, sensitivity during growth and finish etc.

Is that why the T-Max B&W films seem to require extra Fixing and washing to get rid of the colour cast that sometimes remains. Also the mention in the data sheets that one should only use fresh fixer?

 

[gone]

Real-time keeping (testing 5-year old film that was kept as recommended) is of little value. After 5-years the formulation and the raw materials have changed so the data is of little value.

This was very valuable information, and something I never even considered. Probably because I don't buy expired film, and shoot up everything far before it's expiry date.

 

[AgX]

While I'm sure that reduced use of silver was a business advantage of the T-Max films, the quality improvements came from being able to make smaller, flatter silver grains (with less silver in them) respond as well or better to light.

One should not underestimate that "business advantage". The costs of silver were and are a major topic in film manufacture.

 

[koraks]

When I asked my boss why the Agfa didn't he told me it was because the Agfa had so much silver in the emulsion it was in no need of use by dates.

I think this is a nice example of how myths emerge. There are two parts to it: genesis and perpetuation.

Genesis: someone observe that (1) Agfa papers have a high silver content and (2) Agfa papers don't have expiration dates. They conclude that these characteristics are related. Note that no evidence is offered of this supposed causality, so we can't really assume it holds true.

Perpetuation: someone recounts something they've heard long ago. They may or may not have full recollection of all the relevant details, but the gist of the argument remains (at least, we assume it does...) Whether they themselves actually believe it or not, they offer the information they obtained in a matter-of-fact way: this is what I've heard, make of that what you will. Then, someone else comes along, remembers it and recounts it...etc.

Nobody in this chain is lying, purposefully trying to distort reality or otherwise play tricks on the rest of us. It's for all we know all in good faith, and why shouldn't it?

Before you know it, internet lore has it that silver-rich papers last longer. That silver-rich films have better tonality or somehow 'hold more tones' or whathaveyou.

Before you know it, people like Bob Shanebrook have gotten so scarce that nobody is in a position anymore to separate the wheat from the chaff.

PS: among amateur photographers I know, the story is that the longevity of papers like Portriga derives from the presence of cadmium. Make of that what you will. I don't know and have never looked into the matter, but I have no reason to doubt that cadmium was used in the manufacture of papers. AFAIK that's an established fact. What I do not know is why it was there, and I don't expect that it was included to make the paper last longer. I honestly don't know if it had that (unintended) effect.

 

[halfaman]

PE explained that high silver contents on 1950-1960's films were related to poor efficency of silver halides sensitization, as this process improved so the silver content decreased. Only slide film needs higher silver contents.

 

[schyter]

thank you all for the nice discussion full of information.
There remains only one question which is probably marginal and which perhaps will not have a scientifically accepted answer.
Technically, what could a film with more silver give back to negative film in general terms? (more/less sharpness, more/less soft, etc etc)
Ultimately ... could it generate old-style results?
Many thanks to all !

 

[koraks]

I don't think there's any one characteristic that would be influenced solely by silver content per surface area of film. It'll always be a combination of film properties that determine how it looks. You could make a film that looks old-fashioned in whatever way you define with a lower silver content and conversely, throwing more silver at the problem just by itself won't create an "old fashioned look" all by itself. I think the whole silver content issue is one that doesn't hold much water in the reality of film manufacturing. It's a bit like arguing that the rubber content of the tyres define the driving qualities of a car. It plays a role, somewhere, but as an isolated variable it doesn't make sense to focus on all by itself. Anyway, that's the way I see it, feel free to argue otherwise.

 

[AgX]

I think this is a nice example of how myths emerge. There are two parts to it: genesis and perpetuation.

Genesis: someone observe that (1) Agfa papers have a high silver content and (2) Agfa papers don't have expiration dates. They conclude that these characteristics are related. Note that no evidence is offered of this supposed causality, so we can't really assume it holds true.

If they even had high silver content...

I mean, manufacturer #2 of the western-world of course had a huge silver consumption, the same time a lot of R&D resources.
That such a manufacturer would be behind their competitors (as "high silver-content" in this context means just this) and loosing money by this, would be surprising.
Well, one then could argue that they lost money on an other activity, just to stay in that market and to feed the sale of their consumables, a activity thus cross-financed. But would then they willingly loose money on their main, consumables market?

You had it about myths. Well, part of the coming into life of a myth is unwillingness to question ideas. That questioning not necessarily then would yield truth, but at least would not let myths emerge.