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  1. #31
    Ole
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    Speaking as a moderator, a digital representation of an analog product is - well, what APUG is about, really!

    A picture in a thread to explain what the blades look like is not only acceptable, it's most appropriate.

    Besides, I want to see what it looks like
    -- Ole Tjugen, Luddite Elitist
    Norway

  2. #32
    Photo Engineer's Avatar
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    Prototype Film blade

    Ok then, here are two pictures of a prototype film blade. It makes 2 4x5 coated areas on one piece of 5" x 12" film and uses 6 ml of solution to coat that area when gapped at 5 mil.

    This is the first anyone on the internet is seeing these.

    Sorry for the flare from the flash, but it is rather dark here and the blades are highly polished.

    PE
    Attached Thumbnails Attached Thumbnails filmblade1.jpg   filmblade2.jpg  

  3. #33

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    Quote Originally Posted by Photo Engineer
    I coat from .002" to 0.010" with no problem. The pictures I have posted here were coated at 0.005" (5 mil). At 5mil, the average 8x10 requires 12 ml of total solution, but the active ingredients may be adusted based on desired dmax and contrast.PE
    Ok, I'm pretty new to this alternative process stuff. Well, actually, really new compared to most of you. So these may be really stupid questions. But I find that I've been using about 2-ml (maybe a skosh more or less) of sensitizer solution per coat on 8x10 VDBs, using Arches Platine (I've just did a few on Rising Stonehenge today, it's a lot more absorbent than Platine). I've been wondering about my Dmax as I print mostly on Azo which has very good Dmax and very rich blacks. So far I'm not close, but given that these VDBs are mat finish I'm not expecting similar (is that a correct expectation?). My prints do have a lot of scale, but it's shifted up more than I'm use to. I would like more Dmax, but I'm already getting some small pooling of solution at the edge of the print after 4 to 5 passes with a glass rod, so more solution doesn't seem to the answer. How does Photo Engineer use 12ml per 8x10? Should I be using much "thicker" coatings? I thought thin was better. What's more dominant in getting more Dmax (while retaining highlight detail), more coating, more print exposure, or higher contrast negatives?

    Thanks. This is much more fun than using Ctrl-Print (but what about using giclee printing method for coating sensitizer, eh?)

  4. #34
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    Quote Originally Posted by TheFlyingCamera
    at least get yourself a nice but inexpensive Hake brush
    If you want to use a Hake brush spend the money to get a good one.

    Connoisseur brand hake brushs are the creme de la creme of hake brushs. From the first time to the last time you use one they won't shed - ever! They are soft and don't clump when wet. This is the only brand of hake brushes that I've used that isn't a piece of crap except for Winsor Newton brand which I think maybe the same brush.

    I use my Connoisseur to coat cyanotype and gum only but you could use them for other processes. But they do come with a price, IOW they aren't inexpensive.


    Check here for sizes and pricing.

    http://www.c2f.com/html/productlist....goryID=P-79318

    The best glass rods are the ones sold by Bostick and Sullivan, simply because the handles give excellent control of the rod allowing light pressure to be used, resulting in strait coating passes.

    For ferric salt based processes the magic brush can't be beaten.
    Don Bryant

  5. #35
    Photo Engineer's Avatar
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    Quote Originally Posted by middlecalf
    Ok, I'm pretty new to this alternative process stuff. Well, actually, really new compared to most of you. So these may be really stupid questions. But I find that I've been using about 2-ml (maybe a skosh more or less) of sensitizer solution per coat on 8x10 VDBs, using Arches Platine (I've just did a few on Rising Stonehenge today, it's a lot more absorbent than Platine). I've been wondering about my Dmax as I print mostly on Azo which has very good Dmax and very rich blacks. So far I'm not close, but given that these VDBs are mat finish I'm not expecting similar (is that a correct expectation?). My prints do have a lot of scale, but it's shifted up more than I'm use to. I would like more Dmax, but I'm already getting some small pooling of solution at the edge of the print after 4 to 5 passes with a glass rod, so more solution doesn't seem to the answer. How does Photo Engineer use 12ml per 8x10? Should I be using much "thicker" coatings? I thought thin was better. What's more dominant in getting more Dmax (while retaining highlight detail), more coating, more print exposure, or higher contrast negatives?

    Thanks. This is much more fun than using Ctrl-Print (but what about using giclee printing method for coating sensitizer, eh?)

    Well, I've coated VDB with these blades and they work well, but you have to have something to thicken the material as this relies on viscosity for proper spreading on the paper or film.

    With this method, you can precisely control the amount of chemistry on each square meter of paper as well.

    Glicee is a digital technique which is beyond the scope of this forum.

    PE

  6. #36

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    Quote Originally Posted by middlecalf
    How does Photo Engineer use 12ml per 8x10? Should I be using much "thicker" coatings? I thought thin was better. What's more dominant in getting more Dmax (while retaining highlight detail), more coating, more print exposure, or higher contrast negatives?
    The only way to get 12ml of solution on a piece of 8X10 paper is to use some additive that will increase its viscosity, gum or gelatin for example. Of course, this will make it more difficult to get a smooth coating.

    You will not be able to get Dmax with Pt./Pd. as high as AZO with normal methods of printing. About the best anyone can do is a reflective density of around log 1.60, and that is not easy to achieve. Printing several layers might get the DMax up to 1.8, but for more than that I think you wil need to apply the sensitizer in a gelatin or gum emulsion that keeps the solution on the surface of the paper and gives it gloss. But that would significantly change the character of a Pt./Pd. print, when what many people really like is the flat matte look.

    Sandy

  7. #37
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    Sandy;

    By varying the paper surface type and the amount of gelatin / chemistry in my mix, I can get surfaces varying from high gloss to matte. I have also made coatings on canvas, vellum and watercolor papers with good results.

    The final result in my case depends more on ratio of binder to chemistry and to the paper surface.

    PE

  8. #38
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    The comment on giclee sparked a thought PE, have you ever tried spreading emulsion using a silkscreen? I'd think a polyester 300 mesh using a soft squeeegee might give a fairly even coat and is low tech enough for most folks to try for grins and giggles. The texture from the mesh would smooth down a bit on standing after application if the emulsion flows enough.
    Gary Beasley

  9. #39
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    Gary;

    I did silk screen printing back in HS. Yes, it works. You don't get the option to control the spread of chemistry, but it works.

    BTW, the coating blades are now posted for sale on the Formulary web site.

    PE

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