The same time we here at Apug are offering for free a whole lot of information. Outside this internet thing people would have to pay money for such tutorials.
Originally Posted by ParkerSmithPhoto
And many of us paid a lot of money to gain that knowledge (trainings, books etc.)
The figures in the op equate to about 109 grams / 1600 sq ft or about 68 mg / square foot of silver (109 g/1600 square ft = 0.068 g/sq ft). Since B&W film averages more than that per square foot, and color film averages much more than that (about 3X that of B&W), I have to discount the OPs original assumption and what he is trying to say via his expert.
Rare organic and heavy metal compounds (including silver) come in second.
And, labor is the highest cost in the entire equation and that is why Kodak tried for years to speed up and automate production. Which is what put them in a dilemma now.
PE, what is the average g/sqft of modern emulsions?
I found the source. Haist Vol. 2, p. 297, in discussion of the creation of a film with incorporated developers: "A fine grain silver bromoiodide emulsion...was coated on paper base at a coverage of 1900 sqft per mole of silver."
So, I flipped the 9 upside down.
When I heard this figure I was surprised how far a mole can go.
Gerald, I think it's too much to ask everyone to know all the specific jargon of every discipline. Isn't that why there are standard units in the first place? So that scientists can communicate across disciplines and, believe it or not, laypersons can understand and make use of scientific discoveries--if scientists are generous enough to parse them out.
Is there really 3x more silver in C41 than in B&W film? My impression was that with the final density being due to dyes no silver and the overall CI generally being lower, the quantity of silver was generally lower in C41 film. And that C41 fixer seems to be more-dilute than B&W fixer.
Originally Posted by Photo Engineer
As to the OP, the breakdown depends heavily on which manufacturer's film you buy and from which retailer:
- Kodak has HUGE plant, arguably much too large for current market conditions, so capital costs will be significant and likely problematic for them,
- Ilford seems to have more-appropriately-sized plant but it's probably more labour-intensive to run,
- Efke while they existed had a tiny ancient coater and such small runs that they were probably paying more for materials;
- if you buy from B&H or Freestyle, the price is similar to what the manufacturer is selling it for
- if you buy it from a storefront in Australia, the price is 3x as high so 2/3 of the cost is going to distribution & retail
The silver has two functions in chromogenic films: light-sensitivity and image-forming. To a certain extent those functions must be kept apart.
Originally Posted by polyglot
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That was going to be my guess -- a layer for each color (3) and each layer its own silver content.
Originally Posted by AgX
At least with LF landscape, a bad day of photography can be a good day of exercise.
B&W paper materials have no real burden in terms of grain and sharpness for a variety of reasons, and therefore silver laydown is in the range of 50 - 150 mg of Silver / sq. ft. Some papers go as high as 300 using the same units. These so-called silver rich papers waste silver because the technology to get high density from low silver is difficult. Color paper runs in the same range.
B&W films need speed, grain and sharpness and these require lots of Silver! So, they use about 150 to 300 mg / ft sq. Color films may use 300 - 900 depending on these factors.
The density formed depends on the following reactions:
4 Ag + 1 coupler = 1 dye (4 equivalent coupler)
2 Aa + 1 coupler = 1 dye (2 equivalent coupler) < these are mainly in use today!
To go one step further though, the dye has an extinction coefficient or in simple terms, how much bang for the buck! How many moles of dye are needed to get to a given density. The lower the "E" (actually it is Epsilon), the more silver and coupler needed to get a given density. These must be calculated for every coupller / developer pair.
So there, something new for today. You see what a little reading can lead to? You can end up making the wrong statement. Sorry. Please do not equate paper coatings with film coatings ever! Same goes for paper vs film emulsions. These are different areas entirely. And, BTW, I worked with Grant on these types of coatings.
Originally Posted by madgardener
I do use a digital device in my photographic pursuits when necessary.
When someone rags on me for using film, I use a middle digit, upraised.
Film really isn't very expensive. Just use it and don't worry about it. Labor and overhead is where the costs are. Doing my own processing, which is one of my main interests anyway (sure as hell isn't art - lol), I can buy and shoot a half dozen rolls of film and print 8x10's of ALL of it (which I wouldn't) for less than it costs to re-ink the the inkjet printer and buy one box of a decent quality photo paper to print upon, not to mention the extra time / aggravation spent in front of the computer.
Delta 100 in 120 off of Amazon is $4.19. Big deal.
All this has happened before, and all this will happen again.
Exactly most people do not know what mole means. This effectively isolates them from the discussion. Since moles really has no bearing in your argument why mention it at all.
Originally Posted by silvergrahm
Last edited by Gerald C Koch; 01-18-2013 at 01:07 AM. Click to view previous post history.
A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.
~Antoine de Saint-Exupery