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  1. #11
    Photo Engineer's Avatar
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    I don't disagree, provided the expense of ruined emulsion and coating does not bother you. All experimentation with emulsions costs you the cost of Silver content and the paper and gelatin used along with everything else. It is sad to see someone lose a batch of emulsion because a chemical has gone bad or did not respond the same as the last experiment.

    PE

  2. #12
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    That's certainly true. Riddle me this, would chlorophyll have any effect on standard b&w VC papers? I know it's hard to say w/o testing, but what do you think?

  3. #13
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    IDK. I've never tested it. And, if it fails, you have no way to tell if your chlorophyll was good and didn't work or bad from the start. Besides, for a reliable test you need a spectrosensitometer to test the coating just as I do. Or you need to give it pure red light exposures to test it.

    In addition, chlorophyll is not a "true" red sensitizer. A true red sensitizer is cyan in color and not chlorophyll green. This is just an approximation.

    PE

  4. #14
    Mustafa Umut Sarac's Avatar
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    Thank you Chris !

    You got the big award.

    Book says Chlorophyll could be coated to the dry emulsion plates for few seconds.

    I think this open the gates because it is difficult to process liquid emulsion at full dark and if I can do it to sprayed dried emulsion , everything becomes easier.

    Be sure , chlorophyll is one of the widest researched substance and you can find it from local university , biological medical distributor , lab or Sigma.

    May be excessive amount of yellow comes from this formula at some autochromes.

    May be Ron gives more detail.

  5. #15
    holmburgers's Avatar
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    But can other sensitizers be bought at remotely reasonable prices by a "civilian" individual?

    The Lumiere's emulsion was supposedly not truly red sensitive, or so I've read. Due to Umut's interest in unique colors and representations, I think it could be a viable avenue.

    But IDK either, I just enjoy giving a historical perspective, wherein old & forgotten methods might be resurrected.

  6. #16
    Mustafa Umut Sarac's Avatar
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    Ron ,

    I think You are right , living organisms are not predictable.
    What do you recomment to sensitize full spectrum ? To the dry plates .
    Chris visit H. W. Sands Corp , go to catalog and search sensitizers - if this is correct - in red.
    You can learn the nanometer from my french book scan post

  7. #17
    holmburgers's Avatar
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    I can't find sensitizers on their website for some reason. I recall that they are quite expensive, Ron would probably confirm that.

    What do you mean from your book scan? As in, by analyzing the red/orange particle in the scan? As close as you can get to the upper 600's will be your best bet.

  8. #18
    Mustafa Umut Sarac's Avatar
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  9. #19
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    Sensitizing dyes in general run about $100 USD / gram. But, since you only need a small quantity such as 10 - 100 mg / 109 g of Silver, this is quite a bit of dye to work with. For red sensitivity you need a dye that sensitizes in the region of 650 - 700 nm. If you go longer, then it is an IR dye.

    There are several dyes that I have posted here that can be bought at Sands. The red dye is a "J" aggregate former though and is only a red sensitizer on a Bromo-Iodide emulsion. It forms 2 layers that turn a green sensitizer into a red sensitizer. It is, in fact, the dye used in Kodachrome.

    PE

  10. #20
    Mustafa Umut Sarac's Avatar
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    Ron ,

    You are seeing the graphic hereabove.
    So please select the sensitizers which will work like above graphic minus liquid light graphic.
    I dont know the sensivity of liquid light but you guess in your mind one.

    Plus , at picture says that they did a spectrographic test to dyed starchs and
    violet UV to 500
    vertes 490 to 570
    and orange 570 to 580 found.

    Umut

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