Masking/Cropping Prints

Discussion in 'Alternative Processes' started by Ian Leake, Jun 19, 2009.

  1. Ian Leake

    Ian Leake Subscriber

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    I'm experimenting with making prints with cropping masks. So far I've tried masking the negative with rubilith tape (which didn't block UV very well) and with sheets of film (which blocked the UV but left me with poor contact between the negative and the paper surface). I've also tried masking the paper before coating with mixed results.

    Does anyone have any tips for masking negatives for UV exposure processes? Or has anyone got a reliable technique for masking the paper before coating?

    Thanks in advance.
     
  2. payral

    payral Member

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  3. colrehogan

    colrehogan Member

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    I'm glad I saw this thread as I am also planning to experiment with masking on my pt/pd prints. :D
     
  4. Ian Grant

    Ian Grant Subscriber

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    When I did a lot of graphics work back in the 70's/80's combining negatives with text etc we always made masks from lith film. This is easy and cheap.

    Ian
     
  5. Ian Leake

    Ian Leake Subscriber

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    Thanks for your fast replies... A couple of follow up questions though...

    My French is pretty bad... Is this the thin medical tape that's very thin, almost like thick tissue?

    I've never seen this done. Can you explain a bit how you did it?

    Thanks again.
     
  6. payral

    payral Member

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    My French is pretty bad... Is this the thin medical tape that's very thin, almost like thick tissue?

    yes it's used to apply a dressing and it's very thin. Coating doesn't go through.
    Boarder is very clean, I take it off just before drying the coating.
     
  7. gwatson

    gwatson Member

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    Hi Ian

    I might be able to expand a little on the method Ian G suggests, since this sounds like the method I use.

    Ruby lith film is basically a sheet of mylar with a clingfilm-like layer of lith film. You score your mask on the film side and peel away the red film. The mylar sheet can then go between the neg and light source (film-side down). I have only found the film on *bay in the UK, but I'm sure you can get it elsewhere.

    Cheers

    Geoff

    PS: Sorry to Ian G if this is not the method he suggests.
     
  8. Akki14

    Akki14 Member

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    Drafting tape for masking before coating. Make sure you rub it down on the edge.
     
  9. Ian Grant

    Ian Grant Subscriber

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    Quite different, we used to make a photographic mask often from a drawn piece of artwork on lith/line film, processed in Formalith developer, (AN79/D85) these developers give good sharply defined edges. Often we'd make a 5x4 positive and then enlarge it to make a larger negative.

    Ian
     
  10. gwatson

    gwatson Member

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    Hmm. Yes, quite different. Sorry: didn't read your response correctly and assumed you were referring to Rubylith film.

    Geoff
     
  11. wlambert

    wlambert Member

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    I make palladium prints from 8 x 10 negatives and most of my negatives are cropped at least slightly. Arentz, 2nd edition, p. 92, recommends Rubylith masking paper, but my attempts at mask cutting using Rubylith were not successful. Perhaps I did not have the correct type of Rubylith, but I found it very difficult to measure and cut straight lines in the very curly material which an art store sold me. I kept hearing of golden rod paper as a good masking material. When I asked a knowledgeable salesperson at Xpedx paper company (www.xpedx.com) about golden rod paper for masking 8 x 10 negatives he suggested I use 11 1/8 x 18 5/8 inch AB Dick 360 SC Pre-Ruled masking sheets (Colorlok Precision Pre-Press Products), available in boxes of 100 sheets. They work perfectly for me. (Interestingly, the masking material shown in Arentz's Fig. 10.1 appears identical to the AB Dick sheet, not Rubylith, at least not the Rubylith I had tried to use.)

    Briefly, here is how I make cropping masks for my negatives. (In the end an 8 x 10 negative will be taped over a retangular hole in an 11 x 14 masking sheet. I use a Bostick & Sullivan 11 x 14 inch printing frame for printing under UV bulbs.) First I trim the masking sheet to ca. 11 x 14 inches by cutting 4 inches off the end with the catalog number and 3/4 inch off the other end. After trimming, the line labeled "7" becomes the center of the sheet, and I measure out from it in both directions 1/2 the dimensions of the mask opening. Measuring in this fashion guarantees that the mask opening will be centered in the middle of the sheet. Mark each side of the to-be-cut mask opening with a short pencil mark. You do not have to draw the entire outline of the mask opening.

    Place the masking sheet on a cutting mat. (I use Light Impressions No. 20198 cutting mat, 24 x 18 inches.) Lay a steel straight edge on a pencil mark and align it parallel to the closest grid line. Cut the masking paper by drawing an Exacto knife along the steel straight edge. I have found that the Exacto No. 16 blade works well and does not wobble like the No. 11 sharply pointed blade. Overcut the corners about 1/4 inch. Repeat for the other three sides of the opening. After cutting the opening, turn the sheet over and cover the overcuts with a piece of 3/8 inch Rubylith tape. One short piece of tape will cover both cuts if placed diagonally at the exact tip of the corner. Overcutting and taping guarantees sharp 90 degree corners. After taping the overcuts, turn the sheet back over and tape the negative to the front (lettering side) of the sheet (non-emulsion side touching the paper) using several short (1-2 inch) pieces of 3/8 inch Rubylith tape---I keep the tape in the clear film edge and don't let it stick onto the image area. It is best to do the taping on a light table so you can position the mask opening exactly (as shown in Arentz, Fig. 10.1.) For printing, place the masked negative in the printing frame emulsion side up and place the coated paper on top ---paper coating against negative emulsion. I leave the negative permanently taped to the masking sheet which makes it convenient for reprinting.

    This system works well for me. I get straight sharp edges and perfect corners. For negatives larger than 8 x 10 larger masking sheets would be needed. I haven't had occasion to check with Xpedx to see if larger sheets are available.
    Wayne Lambert
     
  12. Mateo

    Mateo Subscriber

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    [​IMG]

    this is how I do it, the masking sheet is for a heidelberg gto 52. they come in 16x20 sheets. if you're printing pt/pd and your exposures are less than 10 min they mask perfectly. if your negs are real heavy some lines will show in the masked area.

    http://www.apug.org/gallery/showphoto.php?photo=44570&ppuser=62
     
  13. Ian Leake

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  14. wlambert

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    I had it in my notes but forgot to mention Stan Klimek's masking discussion in Arentz, 2nd edition, p. 215. He describes the advantage of overcutting the corners and also has instructions for using Rubylith D3R as the masking material.
    "Arentz," of course, refers to Arentz, Dick, 2005, Platinum & Palladium Printing, 2nd edition: Elsevier/Focal Press.
    Wayne Lambert
     
  15. Rick A

    Rick A Subscriber

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    There is a liquid masking emulsion that silk screen printers use, I've forgotten what it is called(its been years since I've done any silk screening)That is just for blocking UV during exposure, and if I remember correctly, it washes off with water. You could check with a graphic arts supply for some.
    Rick