"Silver Rich", the marketing buzzword

[WarEaglemtn]

I keep reading of the "silver rich" emulsions in paper. Many who have tested with densitometers have shown the amount of silver in a paper and the maximum density aren't necessarily the same thing. It is how it is formulated & made. Some papers with a lot of silver don't have the blacks of other papers with less silver.

Anyone with "silver rich" have any way of actually showing how much silver is in the paper? Something like 'grams per square meter' or something similar? Would be nice to know, rational or not, if the claims are anything more than marketing hype. Kind of like the old claim of "Bergger is just like SuperXX". Anything to sell a product.

 

[clay]

Some of the so-called silver-rich films can't build any decent density at all, and have trouble creating a transmission density in excess of 2.2-2.4, which is not enough for some non-silver work given a 0.3-0.4 B+F. Likewise, it has been shown over and over again by knowledgeable scientists that silver content is only correlated to reflection density in papers to some point, beyond which other factors become more important. I think the whole silver-rich myth appeals to the love of conspiracy theories that we all have. We would love to believe that the 'big guys' are screwing us over with substandard products just to save money on manufacturing costs.

But the fact is that you can prove that some of the T-grain films that use much less silver than some 'old style' emulsions are capable of providing a much more flexible range of contrasts along with potentially very high transmission densities (I'm talking in excess of 3.6 LogD). So this question occurs to me: If you can get all the transmission density you need with less silver and better manufacturing techniques, is it not ecologically unsound to knowingly use a film where the excess silver apparently does not provide any photographic benefit, and is in effect wasting a finite natural resource? And all to save a few dollars on a box of film?

 

[Aggie]

High silver content, and the term silver rich are the same thing, just a matter of symantics. Be careful WarEaglemtn. There was a big flame war that erupted here on apug over the use of the term silver rich. There are those who say that it is not a term/word that is in usage or to be found anywhere. Even though there are many places where the term is found.

 

[Flotsam]

A true silver rich film:

 

[Photo Engineer]

We used both words (High silver and Silver rich) to convey the same meaning. That meant a high amount of silver / unit area. We used mg/ft sq at EK, an interesting mix of English and Metric.

In any event, high silver is usually coated when the film or paper cannot reach the appropriate contrast or dmax with what would be a normal amount of silver for that product by a high end manufacturer. It is also used when the product needs it to attain the proper speed. (this assumes all silver is exposed and developed which is essentially the case in high end low silver products)

X-ray film is the most silver rich or high silver product on the market, and that is because it is needed to capture the exposure without huge doses of X-ray to the subject.

Emulsions often have an inherent low contrast, and this is often due to what we called 'dead grains' or grains with insufficient sensitiviity to be exposed or developed normally. Therefore, you can coat more silver to get more usable grains and let the dead grains remain dead. Major manufactureres have methods in place to activate these dead grains and this allows them to coat lower silver. These methods are very complex and involve lots of exotic organic chemicals or precious metal salts.

In my own emulsion making at home here, I am trying to create a hybrid that will allow moderate silver levels and a less complex method to making. If I tried to coat a low silver emulsion comparable to what EK coats, it would be too complex or too expensive for a hobbyist or artist.

This is why I'm trying to re-create the moderately silver rich coatings of the 40s - 60s.

PE

 

[jgjbowen]

Where do you purchase photosampan 25? It must be imported! Is it available in an asa 6400 speed?

 

[ann]

i do believe he is playing with us. check the name on the rebate and the compare to his on line name.

also, that appears to be a photo of silver bars, am i correct?

 

[Flotsam]

Hey, With 50 grams of 999.0 Silver per 24x36mm frame, FlotsamPan is a truly Silver rich film.

 

[PeterB]

X-ray film is the most silver rich or high silver product on the market, and that is because it is needed to capture the exposure without huge doses of X-ray to the subject.

PE, does this mean that higher speed B&W films (non X-ray film) have more silver ? I thought that (among other things) higher speed was achieved by having larger (rather than more) grains of AgX.

regards
Peter

 

[dancqu]

Anyone with "silver rich" have any way of actually
showing how much silver is in the paper? Something
like 'grams per square meter' or something similar?

I've read Kentmere's print paper PDF. Of the several papers
they describe in detail two were mentioned with their
silver content. One had 1.6 and the other 1.7 grams
per square meter. Very much in line with a source
posted by Helen B. some months ago.

I use 1.6 grams as an amount when calculating the
capacity of fixers, particularly with regard to
achieving archival results.

I've given some thought to a method of quantitatively
determining the amounts of silver in paper. I think
it might be done using S. thiosulfate along with
the ST-1 test. Dan

 

[eumenius]

Yeah, silver-richness just appeals to basic instincts of human (in some ways gold toning and the whole platinum process do, too ). Is TMax a silver-rich film? Why people often end with blocked highlights? Dmax and contrast of emulsion just are not related directly to silver content, so all this silver-rich buzz looks indeed a market trick. It's like selling some very very expensive skylight filters to people (d*&*^%l included), claiming that they would prevent any blue casts, and that's with modern color materials! ))))

 

[Photo Engineer]

PE, does this mean that higher speed B&W films (non X-ray film) have more silver ? I thought that (among other things) higher speed was achieved by having larger (rather than more) grains of AgX.

regards
Peter

For a given grain size, you can increase speed within certain limits just by increasing silver spread, but you also get more contrast and dmax which are on the minus side.

This is due to the 'capture' of photons by more silver.

To go to a truly higher speed, one must increase grain size.

In a given film though you can have two emulsions with the same grain size and different speeds through the use of iodide, dye, dopants and this is due to increases in efficiency.

So, there are many ways to get more speed. This is how todays films are higher speed and lower grain BTW, by higher efficiency at the same grain size. It is called the speed/grain ratio.

PE

 

[Photo Engineer]

I've read Kentmere's print paper PDF. Of the several papers
they describe in detail two were mentioned with their
silver content. One had 1.6 and the other 1.7 grams
per square meter. Very much in line with a source
posted by Helen B. some months ago.

I use 1.6 grams as an amount when calculating the
capacity of fixers, particularly with regard to
achieving archival results.

I've given some thought to a method of quantitatively
determining the amounts of silver in paper. I think
it might be done using S. thiosulfate along with
the ST-1 test. Dan

Silver spread is measured in g/meter sq or mg/ft sq. Your measure above of 1.6 grams per square meter is about 160 mg/ft sq in 'round numbers'. This is not unreasonable for a B&W paper. I have seen them as high as 250 - 500 mg/ft sq and as low as 50. It depends on how much silver develops and how dense the silver image is.

When processing film or paper, we used to assume that 30% of the silver was developed to a silver image and the other 60% was fixed out. This figure worked well for exhaustion calculations of developer and fix.

PE