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  1. #131
    holmburgers's Avatar
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    And presumably it's a red sensitizer, right? Are all cyanines gonna be on the red end of things? I guess that would make sense... hence cyan!

    I think it'd be really great to get a big list of sensitizers, complete with references outlining where it's mentioned, by whom, when, etc. Then as we learn things about them we can fill in the rest of the information.

    Unless I'm just missing something really obvious, I don't think a comprehensive sensitizer survey exists. Something to strive for at least.
    If you are the big tree, we are the small axe

  2. #132

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    Do not automaticaly exclude all green sensitizing dyes from the red sensitizing list. When I started working with green sensitive SDE3008, I got very frustrated when my "green sensitized" emulsions, with only SDE3008 kept turning bright violet. I, in fact, had a panchro emulsion and did not know it. It did not seam funny at the time. But I was shure I had not made an adition mistake. Yet the evidence said I had. Or so I thought.
    As it is turning out, I do not need a second dye, SDA3057, for red sensitzation.
    Bill

  3. #133

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    Quote Originally Posted by holmburgers View Post
    I think it'd be really great to get a big list of sensitizers,
    Perhaps these dyes (www.few.de/English/index.htm) will be part of that list as well.

  4. #134
    Photo Engineer's Avatar
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    Excellent list of dyes at Few Chemicals. Kodak is using water soluble dyes in some of their current products.

    PE

  5. #135
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    Quote Originally Posted by holmburgers View Post
    Ok, update to an old(ish) thread.

    This dye, Erythrosine B (CAS: 54530) or Acid Red 51, is available here on eBay for chump change. This dye is in the Kodak list above.

    I'm really interested in finding cheap sensitizing dyes for spectral sensitizing, and not necessarily because I am going to try to make a color-sensitive film tomorrow, but to put the possibilities forth so that anyone making emulsions might be inclined to experiment with this stuff down the road.

    Sure they might not be the best or most efficient, but they will work, no?

    Also, to make panchromatic dichromated gelatin for holograms they use methylene blue as a red sensitizer and Rhodamine G6 for blue/green. Do these dyes have any effect on silver-halides?
    Hi All,

    I'm bumping Chris's comment to the front of the line with an example of how effective the older (cheaper and available) sensitizers can be. I'm using erythrosin in my current favorite emulsion. The ASA (old term for old emulsion ) is hitting around 125 at high summer, sea level, on the 45th. Higher in the mountains. The red food dye is what makes this possible. Right now, I have the first of my attempts with pinacyanol chloride and pinaflavol drying in the darkroom. It would take the wildest of luck to make the first experiment successful, but I'm sure it will get there --- because it got there before. That's the beauty of this. Pan (or even near-pan) emulsions open up a world of possibilities, most notably color -- my Holy Grail. But, also hopefully, these kinds of film speeds even in the winter.

    Anyway, all this was mostly an excuse to share a video from my part of planet. http://video.msnbc.msn.com/rock-cent...7076/#48007076 and my take on the event: http://www.thelightfarm.com/cgi-bin/...tent=27Jun2012.

    Best of weekends with lots of photography -- whatever your camera.
    d
    www.thelightfarm.com
    Dedicated to Handmade Silver Gelatin Paper, Film, and Dry Plates.

  6. #136
    holmburgers's Avatar
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    Hi Denise,

    I'm very interested to know how it's going with your pan sensitizing. According to your most recent post on TLF it sounds like things are going very well (??). Your ortho emulsions are looking really great too!

    Yeah, even near-pan is something exciting. Afterall, Autochromes weren't really sensitive to deep red if I understand correctly; mostly orange.

    Bi-packs, tri-packs, screen-plates; I think things are moving in this direction... and it's very exciting.
    If you are the big tree, we are the small axe

  7. #137

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    Hi All,
    Just to let you all know that I ain't dead, I will write of my current status with regard to emulsions.
    I have decided to suspend my own work on finding a panchromatic (set) of sensitizing dye(s). Due to my growing impatience to get back to making art, I will settle for my existing system which uses Sands SDE3008 as my sole sensitizing dye. At least in my system this dye sensytizes evenly across the visible spectrum in open daylight. At least as I can judge from a Kodak Color Card and actual photographs. This Dye is ridiculusly expensive. So I will be watching this forum and Denise's TLF for "pointers". But I fear that I am geting, temperarily I hope, burned out with research.
    I am now making my own AgNO3 to save in costs. A little risky, but worthwhile from a cost standpoint.
    My first atemps at "real art" using my emulsion will be with tri-color Carbon Transfer, using my existing emulsion to make in-camera color seps. Then I intend to use the emulsion itself , pigmented, in place of gelatin in the actual Carbon Print.
    For now,though, I will just be a "lurker" on this forum.
    Cheers,
    Bill

  8. #138
    kb3lms's Avatar
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    A referece work

    IDK if this has been posted before, but download a copy of this excellent reference, "Photography, It's Materials and Processes" and read the chapter entitled "Color Sensitizing of Photographic Emulsions." Very good explanation.

    http://archive.org/details/photographyitsma001646mbp

    According to archive.org this book is out of copyright and is publicly available. Haven't read the rest of the book yet, but I imagine it is just as good.
    Last edited by kb3lms; 07-05-2012 at 12:19 PM. Click to view previous post history. Reason: Fixed link
    All this has happened before, and all this will happen again.

  9. #139

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    Your link seems to be bad.

  10. #140
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    Sorry, the link is fixed now. Jason
    All this has happened before, and all this will happen again.



 

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