I have never regretted not resisting temptation. Where's the fun in that? Life is short. Play with silver.
Possibly. One major role of excess silver in printing out processes is that it is used as a halogen acceptor. If you can find another suitable agent for this role (besides addition of alpha-hydroxy polycarboxylic acids that are commonly used anyway), I think there is good chance that it can be done. However, there is little modern research on this kind of stuff for printing out materials.
Originally Posted by Jerevan
Tri-X has more than that. 1.5g per square meter is more like for modern microfilms, copy films, lith films, etc. and modern printing papers.
A standard (old technology such as say, Tri-X) film has, as far as I get it, a silver content of 1,5g per square meter. The same content of silver could also coat the same amount of paper. I am not sure of the Ag content of T-grain films but I believe it is lower due to some manufacturing differences.
First of all, there are lots of films that use 3g or more. But in light of post-1950 emulsion technology (it doesn't have to be state-of-the-art or anything) silver content is merely a marketing hype that is used by some authors and retailers these days. And I don't even think the authors or retailers know the actual silver content of the materials they are talking about. Plus, older emulsions contain a lot of crystals that are not even sensitive enough and they just consumed silver and processing capacity of the chemicals. So, even if a product is indeed silver-rich, it just means technology-poor.
What I am really trying to figure is this idea of "silver-rich" materials. Let's say one makes a film with 3g silver per square meter. Apart from the obvious rise in costs, does it make any sense altering the levels of silver - and is there any limit to how much you can use in an emulsion?
You can put more silver in the emulsion if you want. But only the crystals near the surface get exposed and the bottom ones won't even get exposed enough. Also, if you put too many crystals, they increase light scattering and decrease resolution. Modern tabular grain technology and double layer coating allow a much better tradeoff of these competing factors.
In paper emulsions, the resolution is inherently low and also irrelevant, so you can add more silver with relatively little harm but it is still unwise for the same reasons.
True: I can resist anything but temptation, as Oscar Wilde wrote. I just need to get down to buying a balance to measure things with and I'll be making some basic emulsion in the near future.
Originally Posted by dwross
thanks for the information on the silver content. A few more pieces to the puzzle...
“Do your work, then step back. The only path to serenity.” - Lao Tzu
Jerevan: Excellent. You'll have a great time! Winter is a wonderful time to have an intellectual and artistic puzzle to play with. Right now, a Pacific storm is beating again my windows, and I get to go into a warm, dry, cozy darkroom. Nirvana. Best of luck to you.
I hope you enjoy your winter making emulsions and I wish you success.
It is true, as I have posted before here on APUG and PN that silver rich is a myth. It is not needed to get good quality. But, the myth arose because the old silver rich films had very good quality. We see that in the nostalgia over some of the older products such as Super XX. Even today, some manufacturers advertize silver rich products which have good quality.
We, working at home, cannot easily make double coated film or make t-grain emulsions. They are much more complex than simpler emulsion from this earlier era and the earlier emulsions, while 'silver rich' also can be 'image rich' if I may coin a term here.
Denise has commented on how rich the blacks look in her hand coatings from the Azo type emulsion formula that she is making. This coating is silver rich but is also beautiful to behold. A typical coating contains about 250 mg/square foot or about 1.9 grams per square meter. You typically coat 12 ml per square foot or about 100 ml / square meter. (These will not match exactly as I'm doing the conversion in my head here between English and Metric but that is ball park. I hope I didn't slip a decimal.)
That is about double the level of silver current enlarging paper level, but it works and give such a nice look I just could not resist the result myself. I could lower the silver content with appropriate addenda, but chose not to due to the appearance. This particular formula is also slightly softer in the toe than the Azo formulation and therefore gives better detail in the highlights with less need for dodging.
The matte blacks look like black velvet.
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