Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,535   Posts: 1,544,072   Online: 1110
      
Page 4 of 12 FirstFirst 12345678910 ... LastLast
Results 31 to 40 of 113
  1. #31
    RobertP's Avatar
    Join Date
    May 2006
    Shooter
    ULarge Format
    Posts
    1,130
    Images
    8
    PE, In some of the old literature it talks about using albumen to sub the entire plate. The formula for using albumen to sub the entire plate is: Two large egg whites to 1 liter of distilled water. This is poured on and flowed just like you would the collodion. It then could be cut to any size desired. We also could be comparing apples to oranges here. I'm talking about wet plate collodion and not dry plates. But you could flow albumen on a large plate and let it sit for days or longer before cutting to size and using it to flow your wet plates. I guess that would hold true for coating a dry plate emulsion also. Albumen plates should be used within a few days or stored properly because in hi humidity yeast in the air can react with the albumen and cause contamination spots.

  2. #32
    RobertP's Avatar
    Join Date
    May 2006
    Shooter
    ULarge Format
    Posts
    1,130
    Images
    8
    Also let me add before you do anything with the glass plates you must make sure they are extremely clean. I use to use "Glass Wax" but it is no longer available. Now I use a "Whiting" mixture which is nothing more than 40 grams of calcium carbonate mixed into 50 ml of distilled water and 10ml of 190 proof grain alcohol. Works great.

  3. #33
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,017
    Images
    65
    I am talking only about dry plates. They were not subbed AFAIK nor were the edges prepared in any way. The large 30x40 sheets were coated, dried and then cut into 4x5, 8x10 and etc. There were other large plate sizes besides 30x40.

    A special machine was manufactured that cut the coated dry plates, and also removed the glass dust. All of that technology has been essentially lost.

    I clean my plates with Potassium Dichromate-Sulfuric Acid grease removal solution after a good wash in detergent. I rinse in DW and let air dry before coating.

    PE

  4. #34

    Join Date
    Jun 2004
    Location
    Portland, OR
    Shooter
    4x5 Format
    Posts
    3,268
    Quote Originally Posted by Photo Engineer View Post
    Potassium Dichromate-Sulfuric Acid
    It's an excellent glass cleaner and I remember the days that it rule them all in chemistry labs.

    Now, it's considered environmentally hazardous and not used in most lab applications.
    Kirk

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

  5. #35

    Join Date
    Jun 2004
    Location
    Portland, OR
    Shooter
    4x5 Format
    Posts
    3,268
    Quote Originally Posted by Photo Engineer View Post
    I am talking only about dry plates.
    Do you know if the machines cut the gelatin as it scored the plates? It seems like you would have to do the scoring from the emulsion side to get it to work.
    Kirk

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

  6. #36

    Join Date
    Apr 2005
    Location
    San Bernardino, CA
    Shooter
    8x10 Format
    Posts
    734
    Quote Originally Posted by Kirk Keyes View Post
    It's an excellent glass cleaner and I remember the days that it rule them all in chemistry labs.

    Now, it's considered environmentally hazardous and not used in most lab applications.
    I have read that some people soak their glass plate in a fairly concentrated solution of NaOH. This puts a micro-tooth on the glass and creates a mono-molecular layer of sodium silicate. The later can benefit adhesion.
    Bill

  7. #37
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,017
    Images
    65
    I use so little Dichromate that it is not a problem. It can be reused over and over for this application. The Sodium Hydroxide should work, but IDK how fast it will react with various types of glass. It can make some glass translucent.

    PE

  8. #38

    Join Date
    Apr 2005
    Location
    San Bernardino, CA
    Shooter
    8x10 Format
    Posts
    734
    Hi,
    I would think that soaking the glass plates in NaOH would also serve to smooth out the edges without having to file the edges or sub the edges.
    Bill

  9. #39

    Join Date
    Oct 2008
    Shooter
    Medium Format
    Posts
    139

    Ajax and Green Scrubby

    When I pour my plates, I wash them with Ajax or Comet and scrub the heck out of the edges with a 3m green scrubby. The emulsion I did this with was always a knox-gelatin emulsion (but never again), and I never had any problems with adhesion, no hardener used. Stupid Knox Gelatin will melt right off the plate, though.

    To get an even coat, I put all my plates in the oven and heated them to about 120, just hot enough to where they are almost uncomfortable to hold, then keep them in a stack as I pour, so that the plates behind the ones I'm coating smooth out the temperature across the top plates and keep my fingers from causing thick spots. Unfortunately, the last one generally comes out uneven. If I were smart I'd have one extra glass plate that I didn't coat.

    I think for big plates, you could make a plywood jig to hold them with a tripod mount on the bottom, so you wouldn't have to hold the weight as you tilt it around, just swivel your tripod head. Several layers of warm glass under the top plate should keep it warm enough until the emulsion is completely coated. The only issue then would be to perfectly level the plate once it's been coated. this was the issue that i had, apparently there isn't a level surface anywhere in my house. Maybe a couple of spirit levels glued to the side of the jig would help.

    I'm no expert, just m 2 cents.

  10. #40

    Join Date
    Jun 2004
    Location
    Portland, OR
    Shooter
    4x5 Format
    Posts
    3,268
    Quote Originally Posted by totalamateur View Post
    Unfortunately, the last one generally comes out uneven. If I were smart I'd have one extra glass plate that I didn't coat.
    Get some ceramic floor tiles (they come 12x12 inches) and put them under your stack of glass plates. The ceramic tile should hold the heat for a while and help keep you glass plates warm longer.
    Kirk

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

Page 4 of 12 FirstFirst 12345678910 ... LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin