Brush Marks in Large Platinum Prints

Discussion in 'Alternative Processes' started by bill schwab, Mar 4, 2007.

  1. bill schwab

    bill schwab Advertiser Advertiser

    Messages:
    3,754
    Joined:
    Jun 16, 2003
    Location:
    Meeshagin
    Shooter:
    Multi Format
    Here's a question for you large PD/PT printers. I have been experimenting for awhile with 20 x 20 prints and having pretty good luck, except with images with large and very smooth tonal areas. I'm using a 4 inch richieson brush, but still having problems with brush marks in these areas. How do I go about getting a more smooth coating? I have read about Kerik's use of Everclear with his sensitizer... would this be a soulution? I have also tried double coating which helps, but it is still not satisfactoy. Is there some other trick I am missing?

    Thanks ahead of time for any suggestions.

    Bill
     
  2. Jeremy

    Jeremy Member

    Messages:
    2,767
    Joined:
    Oct 26, 2002
    Location:
    Denton, TX
    Shooter:
    Multi Format
    You can also try adding PVA to your coating mix as this will give you a bit more time before it sinks into the paper. Clay Harmon showed me this technique and he'd be the guy to inquire further about going this route.
     
  3. wm blunt

    wm blunt Member

    Messages:
    171
    Joined:
    Jul 13, 2003
    Location:
    Missouri
    Shooter:
    Large Format
    Stan Klimek writes in Dick Arentz's book about coating his prints over a light table with a low watt tungsten bulb to get a smooth even coating. A thought.
     
  4. Robert Hall

    Robert Hall Subscriber

    Messages:
    2,047
    Joined:
    Aug 18, 2004
    Location:
    Lehi, Utah
    Shooter:
    ULarge Format
    Why not try a glass rod?

    I know you dont get the cool brush edges, but man does it cover smoothly. I use a lot less solution as well, perhaps even 20% less than with a brush.

    I make mine out of 1/2 glass rods with a piece of glass epoxied to it as a handle. I can make them any size and a 20" wouldn't not be hard to handle.

    I coat on top of a piece of 3/8 safety glass that is 24x30. Easy to set perfectly flat so the solution flows well and doesnt flex at all.

    Best of luck Bill,
     
  5. Robert Hall

    Robert Hall Subscriber

    Messages:
    2,047
    Joined:
    Aug 18, 2004
    Location:
    Lehi, Utah
    Shooter:
    ULarge Format
    Oh, you might try some Tween 20 as well.

    See Bostick and Sullivan for that.
     
  6. photomc

    photomc Member

    Messages:
    3,575
    Joined:
    Jul 20, 2003
    Location:
    Texas
    Shooter:
    Multi Format
    Will 2nd the use of Tween 20 and Everclear (ETOH)...with a qualification on which paper you are using. Tween works great (for me) on FAEW and Arches Platine (COT320) but not on Carnes Cover Stock (aka Platinotype).

    In fact have been printing again this morning (just coated for a 5x7 and 8x10) and the other thing I found last weekend is that by increasing my drop count it helped the coating look better (think I was a little short). But then my temp/humidity would be different from yours - so best advice I can offer is to give each suggestion a try and see which one works for your way of working...BTW, just started masking those brush marks so that they do not show.
     
  7. sanking

    sanking Member

    Messages:
    4,813
    Joined:
    Mar 26, 2003
    Location:
    Greenville,
    Shooter:
    Large Format
    First, make sure you are using enough solution. Then, make sure you quit brushing before the sensitizer starts to dry. The idea is to brush the sensitizer on the paper very quickly, even it out so there are no puddles, and stop. If you use too little sensitizer the coating will dry out very quickly and you will get brush strokes. And if you use the right amount of sensitizer but brush too long you will get brush stroke.

    The additive may help in certain conditions but the key is to use the right amount of sensitzer, brush no more than necessary to even out the coating and remove puddling, and stop before the coating starts to dry. This is much easier to say or write than to do, of course.


    Sandy King
     
  8. bill schwab

    bill schwab Advertiser Advertiser

    Messages:
    3,754
    Joined:
    Jun 16, 2003
    Location:
    Meeshagin
    Shooter:
    Multi Format
    Thanks Sandy... and all. I was getting the feeling I was trying to be too sparing with the sensitizer. I think I have also been working it a little past drying time. I've had some real nice prints since upping my sensitizer, but you are right in saying it is easier said than done!

    Thanks for the help.

    Bill
     
  9. gwatson

    gwatson Member

    Messages:
    146
    Joined:
    Feb 2, 2005
    Location:
    Windsor, UK
    Shooter:
    Multi Format
    Hi Bill

    I sympathise. This has been an issue for me and not on the print sizes you are doing. Really just to reiterate the above advice: I always tended to over-brush. I now force myself to stop brushing when I think I can do one more sweep. I always have sensitiser left, but instead of trying to brush he last of it in, I stop and blot the edge. This means I probably blot 10-20% of the liquid, but it really works (for me at least). Also, I now use a very wet brush (9010) - if you are applying two coats, this is no problem (wash after each coat). Probably trying to teach you to suck eggs, but thought I'd butt in just in case.

    Cheers

    Geoff
     
  10. sanking

    sanking Member

    Messages:
    4,813
    Joined:
    Mar 26, 2003
    Location:
    Greenville,
    Shooter:
    Large Format
    Anothe comment about brushing.

    When you begin to coat you should apply enough pressure with your brush strokes to make sure that the emulsion is being spead to the paper over all of the area of the brush.

    At the end, you should apply little or no pressure, and just allow the brush to flow over the paper.

    Again, easier to describe than do, but the concept is important.

    Sandy