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  1. #11
    Marco B's Avatar
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    Of course, there is another aspect we are forgetting. Assuming an average photo is "18% grey", and that that also translates in 18% silver left after fixing, the amount of silver of an 8x10 sheet might be somewhere in between about 15-40 mg...

    That would mean that the 0.5 g gold could go a very long way in toning 8x10s, if we also take in account that only a small portion of the silver is replaced by the gold based on Kirk's response. If we again, and this is completely guess work!, just for the sake of getting a feel, assume it's 20% percent replaced, than only 3-8 mg of silver needs to be replaced for a single sheet.

    If 3-8 mg of silver translates (and this is another blatant assumption!) in 3-8 mg of gold, than 500 mg gold toner might tone anywhere between 60-160 sheets (just a rough calculation)

    Marco
    My website

    "The nineteenth century began by believing that what was reasonable was true, and it wound up by believing that what it saw a photograph of, was true." - William M. Ivins Jr.

    "I don't know, maybe we should disinvent color, and we could just shoot Black & White." - David Burnett in 1978

    "Analog is chemistry + physics, digital is physics + math, which ones did you like most?"

  2. #12

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    I think that is what the link you posted was getting at, that capacity depends on print density...

    Many people like low key-
    I don't - but...
    as PE has mentioned, D-max is not strictly related to silver content.

    In any case,
    Tetenal's claims their toner should tone about 13 8x10's per liter.
    depending upon yes, how black the image is;

    High Key will give you more prints per Euro.

    How many prints you can do also depends on how other factors.

  3. #13
    Martin Aislabie's Avatar
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    I was trying to find out how much Silver was coated on a piece of virgin photographic paper.

    You have taken it through the next two steps of my thought process

    I am toning for the cold tones achievable with Gold.

    If the print has first been Selenium Toned - to the level where colour change is see in the high tones - what is the chemical action of the Gold Toner?

    This must also affect the Gold Toner baths life (for a given print density)

    Also, I don't know if it is significant but - Gold Toner is missing from both the Tetenal & Fotospeed Web Sites

    Martin

  4. #14

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    Do excuse the naive question please but why does gold toning give a bluish tint instead of a 'golden' tint?

  5. #15
    Marco B's Avatar
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    Quote Originally Posted by Martin Aislabie View Post
    If the print has first been Selenium Toned - to the level where colour change is see in the high tones - what is the chemical action of the Gold Toner?
    Maybe not much at all. If you have a clearly visible shift in tones, much of the available silver may already have reacted with the selenium. In general, I think it's more difficult to control or judge the extend to which selenium toning has taken place, than for example a bleach/tone toner like a thiourea based sepia toner.

    But of course Tim Rudman is the expert, maybe he can tell you something about split selenium and gold toning.

    Quote Originally Posted by hmho View Post
    Do excuse the naive question please but why does gold toning give a bluish tint instead of a 'golden' tint?
    In general, the color of any substance is determined by it's spectral reflectivity. If the reflected light happens to be mainly "blue-ish", as with the substances and complexes created by gold toning, it will look blue.
    My website

    "The nineteenth century began by believing that what was reasonable was true, and it wound up by believing that what it saw a photograph of, was true." - William M. Ivins Jr.

    "I don't know, maybe we should disinvent color, and we could just shoot Black & White." - David Burnett in 1978

    "Analog is chemistry + physics, digital is physics + math, which ones did you like most?"

  6. #16

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    This question is quite interesting and much could be written about it.
    Why indeed is silver black?
    Not long ago, it was debated and ideas put forth that the strands trapped the light... but what color are silver filaments that have been grown to vulgar sizes?!!

    Why are diamonds colorless, (some of them are blue) but graphite grey black and what are the different methods of color synthesis anyway? I asked S.G. to respond to this, because he seems to be the most fluent in this area, but I guess I asked too much... another understatement.

    But the very poorly answered basic question is that the image particle size and shape, (plus x,y and z), change the way we percieve the image's color.

    Buy why and how?

    What is "color" anyway?

  7. #17
    Photo Engineer's Avatar
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    Silver is not "black" in any form. It has some degree of color whether brown or blue. It can also be bright yellow, bright green and etc... Cary Lea Silver is bright yellow and very dense in absorption per unit of silver metal. About 10 mg/sq ft will give a density of 3.0.

    There is no simple rule on color and that is why silver metal step wedges are not used for critical sensitometric purposes. I discussed this in a previous post.

    PE

  8. #18

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    Quote Originally Posted by Ray Rogers View Post
    Buy why and how?

    What is "color" anyway?
    Oh man - there's whole books written on that subject!
    Kirk

    For up from the ashes, up from the ashes, grow the roses of success!

  9. #19

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    Quote Originally Posted by Photo Engineer View Post
    Silver is not "black" in any form.
    Thats why we call it "Black and White Photography"!


  10. #20

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    Quote Originally Posted by Ray Rogers View Post
    Why indeed is silver black?
    What is "color" anyway?
    Black image silver. It appears black because it
    absorbs all wave lengths of our visual spectrum.
    To know why it does that takes one into a study
    of the physics of light and the electromagnetic
    spectrum and their interaction with materials.

    A notable example is Global Warming. Carbon
    dioxide is unaffected by incoming wave lengths
    of the spectrum but absorbs out going heat wave
    lengths of the spectrum. So, the more CO2 the
    less out going energy. The greenhouse effect.
    BIG GREENHOUSE.

    The perception of color, as I understand it, is
    the result of eons of evolution. Not all seeing
    animals perceive color. Dan

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