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Thread: Glass plates

  1. #11
    DKT
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    well, old glass plates can have alot of problems like the glass becomes brittle, or the emulsions flake off. There's a term for that, I can't remember it now, but there's a pattern of decay with glass plates where the emulsion basically falls off the plate due to temp & rh amongst other things. They require different types of environmental conditions than regular film storage as well, so it's not really an incredibly stable media to begin with....

    Like I said, I've never done them before. I'm sorta curious about them though. I was surprised , from talking with one of these guys, how short some of the exposures were. I was always under the impression they would be rather long, but he was shooting at fairly short exposures, although for the life of me I can't recall the exact times right now. It was a pretty bright day though....you certainly didn't need a neck brace or anything for the subjects. Apparently the wet coated plates will have the characteristics of unevenness on the edges, and you'll see a little spot in the corner of the plate where the person's fingers would have been. They hold it by an edge and sort of move the plate around to get the emulsion to spread across it. One guy showed us how to tell the difference between a dry plate and a wet plate based on this sign of where the finger marks were. I'm trying to remember all this now, so I hope I'm getting this right, but the thing about the tintypes was that the iron plate (note: "ferrotypes"--this is the correct term) needs to be varnished for the emulsion. I don't know if you've ever seen an old tintype that has been bent or chipped up? Where the iron has been exposed & has begun to rust? They call that prep work japaned, it's like a lacquer coat almost....so there's more prep work in making tintypes as I understand it than making an ambrotype, which is just the emulsion coated onto the glass, which is sandwiched emulsion side down to another sheet of glass, with black backing to it. It could be flocking material or some sort of paint....they used canadian balsam to hold the plates together , and the whole thing was assembled into a "union case"--I'm sure you've seen old daguerrotypes in those ornate cases? Ambrotypes and sometimes tintypes were assembled this way as well.....so you can make an ambrotype and if you didn't case it up, it would be a negative....the cased ambrotypes are often (not always) reversed to protect the emulsion, but a daguerrotype is always reversed and a different beast altogether.....they're not all monochromatic either--some of them will be handcolored or tinted in various ways. Of the modern ones I've seen, few look like the actual artifacts I'm used to seeing. I don't know if they're "too perfect" or what, but they do look quite real in a way too....

    I'm no expert on this either, but we have alot of these older types of photographs in our collection. Oh well, enough rambling....

  2. #12

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    I know that one of the appeals of the ferrotype was that the exposure times were very short. From what I understand all it is, is a negative that is underexposed with a black backing. This gives the positive effect. Plus they were cheap to make. No printing needed and all you do is develop the origional. This made them very popular apparently. You could set your gear up on a boardwalk very easily and didn't need the headbraces and all that. At the time it was the equivelant of the guy with the polaroid and the colorful parrots at the beach. If you know what I mean.

    I'd imagine too that ferrotypes require less precision in coating than a glass plate. It would seem to me that the glass would show any uneveness in the emulsion far more readily than the ferrotype since the black backing would help hide a multitude of sins.
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  3. #13
    DKT
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    actually it's the same type of emulsion as an ambrotype. It's just coated onto the iron plate that has been lacquered black--japanned--or some later ones were brown as well. An ambrotype is the collodion coated onto glass, and looks like a positive because the negative image is sandwiched with a black backing material of some sort. The tintype has the wet collodion coated onto the black lacquered plate--this makes it appear as a positive in the same way the black backing of the ambrotype makes it appear as a positive. The negative is not as dense as a modern neg--it's thin. As I understand it, the wet plates were faster than they would have been if that emulsion had dried. They coated them, shot them wet & processed them. I've heard it said that the reason why tintypes prevailed, besides the economy of them, was that they were more durable than the others.....the daugerrotypes and the ambrotypes were more fragile, so they were cased up to survive. Tintypes were coated with varnish in the end to protect the emulsion and often just packed into paper folders....we do have some in our collection that are in very ornate cases, with gilded frames and leather casing--these look similar to ambrotypes. Because of that black lacquer though, the tones are really sorta muddy in a way. But I have copied tons of tintypes onto 4x5 film and they hold *alot* of detail, they can be very crisp images, and some of them quite large as well. I've seen them as big as 8x10s....it's just a different tonality.

    Daugerrotypes and ambrotypes are one-of-a-kinds, but I believe tintypes could be repro'd as copyshots (more tintypes) as well. sometimes you can read the little adverts for this work on the back of the folders or later on the backs of CDVs and cabinet cards.....

    KT

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  4. #14

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    Well Jay, you got me curious so I did a search. Here you go, how to make dry plates.


    http://www.edinphoto.org.uk/1/1_early_phot...ino_bromide.htm


  5. #15

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    So where is this liquid gelatine you are talking about?

    BTW in the article they mention add the silver nitrate to the potasium bromide and iodide, remember to do this under a safe light (red) as the film becomes sensitized when you add the silver nitrate.

  6. #16

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    Jay, thanks for the links. Either puerto Vallarta or Mazatlán are good choices. I am more partial to Mazatlán, but really there is not much difference. Enjoy and have a nice trip. Hope next time you get to visit with us.

    PS. Does Dr. Leubner have a web site? or anywhere I can see what he is up to.
    Controling crystal size and growth is not an easy thing to do, and it might be you need a lab with gizmos worth way too much money for the hobbiest to use. When I studies solid state chemistry, most of the stuff required a lot of controls and a thorough knowledge of physical chemistry, at this stage I just want to take pictures and not worry about such things.

  7. #17

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    I understand that Bergger is contemplating bringing a contact paper to market sometime in the future. For those who have not tried Azo with Amidol it has the capabilities to produce incredible prints. The nearest tonal range to Pt-Pd. I know that we who are interested in contact printing on silver should pay heed to the need to support this product. Michael Smith has went out on the limb a long way to keep this excellent product in Kodak's line for the time being. For those who have not done so, I encourage visiting www.michaelandpaula.com.
    This is an excellent site devoted entirely to supporting those who contact print on Azo. My soap box just collapsed, so I'm off to the next street corner. Good luck.

    Regards,
    Donald Miller
    Art is a step from what is obvious and well-known toward what is arcane and concealed.

    Visit my website at http://www.donaldmillerphotography.com

  8. #18

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    uh, Donald I think you want the Azo thread......not glass plates.

    Jay, I checked some of the sites with Dr. Leubner's abstracts and they would seem to be very complicated topics. Anyhow, I am sure with the info you have you can get good results. E bay sometimes has glass plate holders.

  9. #19

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    Sorry, I was responding to the preceding comment about another good contact paper being in order. My point being that we already have one. My apologies again. I'm off to another street corner...Whistling.....
    Art is a step from what is obvious and well-known toward what is arcane and concealed.

    Visit my website at http://www.donaldmillerphotography.com

  10. #20
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