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  1. #21

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    David, while everyone may be right here is what I understand your question to be and maybe some idea of what the different types of B&W prints are:

    Silver Gelatin - which would include silver bromide, silver chloride and chloro-bromide.

    Albumen - made with protein substrate - like egg whites.

    Ambrotype - older process like albumen, I think image was on glass

    Tin Type - like the name says, was in a way the first widely produce image type I think

    There are others, I would suggest a visit to library or search on the net to find some of the others and new definitions (which you could post here for new discussions - only kidding). Hope this helps.
    Mike C

    Rambles

  2. #22
    clay's Avatar
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    Read your own definition more carefully:

    2 a : a substance that consists of particles dispersed throughout another substance which are too small for resolution with an ordinary light microscope but are INCAPABLE of passing through a semipermeable membrane

    BTW, its syllogisms, not syllagisms, and FWIW, they only work if your premises are correct, otherwise....

  3. #23

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    The term emulsion is incorrectly applied to photographic papers. An emulsion occurs when two inmiscible solutions with a definite phase separation are shaken until drops are dispersed in one of the solutions but still have a complete phase separation, as is the case of oil in water.

    A colloid can be thought as an emulsion but in this case the particles are small enough that surface effects become an important part of their behavior and they still have phase separation.An example would be milk of magnesia.

    A solution is made of two or more miscible components with no phase separation, as is the case of sugar in water. Pt/pd, Van Dyke brown and silver salts in liquid gelatin are nothing more than solutions, they are NOT colloids or emulsions. Once they have gone through a chemical reaction they simply become solids embedded in other solids as is the case of silver papers, or they become solids deposited on other solids as is the case of pt/pd or VDB.

    Furthermore the exclusionary condition of a semi permeable membrane is erroneous and misleading, ionic material in SOLUTION can and will be rejected by a semi permeable membrane depending on the size of the atom, type of membrane and physical conditions applied to the separation technique. This is best exemplified by the water purification technique of Reverse Osmosis.

    Webster might know English, but it knows little about chemistry.

  4. #24
    David Ruby's Avatar
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    I'll search the archives but...

    what is a platinum print?

    Palladium?

    Carbon?

    where do you go to search the archives by the way?

  5. #25

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    David, use search from the main page it will return hits for the different topics.

    Platinum Prints are paper coated with Platinum or a Platinum/Palladium mix (these are had coated papers - done by mixing up plt/pd and then spreading the coating onto paper - see Bostick and Sullivan for supplies)

    Palladium like Platinum, except using only Palladium

    Carbon, I do not have any experience with these - see B&S site for info.
    Mike C

    Rambles

  6. #26
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    Wow, I'm sure glad you don't have to know all this stuff to be able to work with it.

    I'd be screwed.

    The bliss of ignorance.



    Michael McBlane

  7. #27
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    I have a hard time calling RC paper Silver gelatin. I figure they are for "proofing" - for evaluating a negative before you put it on good (real) paper. Kind of like the stuff color photos from Walmart come on.

    glitche is INK JET - like that fade fast stuff that spills out of the ol'HP

    Real Silver Gelatin - good old fiber paper with a meaningful byarta layer on it. Preferably silver chloride (best possible monochrome imagees) but if the camera weighs less than 20lbs it will be silver bromide.

    Van Dyke, Kallitype - Silver iron right on the paper - kinda like great great grandmother used to make - really good stuff but not super hi res. Kalitypes that have been selenium toned are almost 3d - also pretty easy

    Cyanotype - iron cyanide right on the paper - beautiful blue - you have to try this one - cheap- easy and too cool to miss

    Aubumen - like silver gelatin except egg whites instead of animal gelatin - glossy hi-res creamy looking images - very cool.

    Platinum/Paladium - like Kallitype except too expensive for me - Supposed to be the best of the best but a good selenium toned kalitype is pretty close.

    There a bunch of other "types" some old and some modern -ziatype is modern. One noteworthy difference is tin type and duerruagge (ok I kant spell it) these metal processes are direct image onto polished metal in the camera with black paint or tar as the black area - no negatives were used the silver area became a very light grey brown. Lots of interesting gasses and poisons and lots of polish. - Kind of like an early polaroid!

    Then there is digitype - an image consisting of zillions of bits that can be used for anything not worthy of keeping past a year or two. These devices can leak in which case you use a "bit-Bucket" to catch the bits as they roll out. Some distortion can occur as can be seen in glitche prints when one ink cartrige gets low or the power goes off in the middle of a 13x19 Pictorico White glossy film. One redeeming thing though - the digitype can be converted into a big negative and then made into a kalitype in which case the 700 hours of learning and 4000 of good printers hard drives monitors and stuff will sort of pay off ... or you can get that 20 lb camera. I have done both and the big heavy camera makes my arms and shoulders big where the digi-type makes my butt big.


    Now you have way too much information
    My photos are always without all that distracting color ...

  8. #28
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    Quote Originally Posted by Jorge
    cut
    A colloid can be thought as an emulsion but in this case the particles are small enough that surface effects become an important part of their behavior and they still have phase separation.An example would be milk of magnesia.

    A solution is made of two or more miscible components with no phase separation, as is the case of sugar in water. Pt/pd, Van Dyke brown and silver salts in liquid gelatin are nothing more than solutions, they are NOT colloids or emulsions. Once they have gone through a chemical reaction they simply become solids embedded in other solids as is the case of silver papers, or they become solids deposited on other solids as is the case of pt/pd or VDB.

    Furthermore the exclusionary condition of a semi permeable membrane is erroneous and misleading, ionic material in SOLUTION can and will be rejected by a semi permeable membrane depending on the size of the atom, type of membrane and physical conditions applied to the separation technique. This is best exemplified by the water purification technique of Reverse Osmosis.
    Quite accurate, Jorge. In addition, we should mention that the active layer on film and paper is technically a suspension. Also there is, as you pointed out, a differeince between a semi-permeable membrane (ro) and an ion exchange membrane (water conditioning et c.) which _will_ transfer ionic material (along with some non-ionic stuff).

    Your acumen, as usual, is appreciated, dr bob.
    I love the smell of fixer in the morning. It smells like...creativity!
    Truly, dr bob.

  9. #29

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    Ah, suspension! that is the word I was looking for. Thanks Bob.

  10. #30

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    At my age, I can use all the suspension I can get!
    Do not question what you have not done, question what you will not try.

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