Wednesday, February 11, 2009

Photopolymer prints

I am posting a few recent prints to illustrate what is currently being printed or has already been created in my studio of recent.
These images are from a larger body of works revolving around the theme Wilderness .

The goal is to create a number of prints for display in a solo show based on the theme.

The series will utilize a variety of printmaking techniques that include serigraphy (silkscreen), block relief surface, intaglio (etching and drypoint) and photographic image etchings using polymer plate technology (a new safe etching process).




Black Fox Lake
polymer plate print with hand colouring

This print started out as a photo taken with my digital camera while on a wilderness excursion in Northern Ontario in late September of 2008. I you scroll down there is a fairly detailed description of the process I use to create these types of prints.
Black Fox Lake is a variable edition of 20 hand tinted photopolymer intaglio prints on Stonehenge 90 lb. acid free white paper.

Fig. 2 shows a mixture of prussian blue and black ink



Fig.2

Process description: Photo polymer plate printing




In this demonstration a photo is printed out as a high resolution grayscale positive on a transparency sheet using a good high resolution dot inkjet printer (like Epson). This is exposed to a UV light source (either natural sunlight or an artificial source) onto the surface of a light sensitive thin polymer coated metal plate. To help create areas in the polymer that will hold more ink for dark shading and also for good tonal variations in the image the process involves first exposing the plate surface to a fine dot aquatint screen. This is followed by exposure of the positive. This is called a double exposure technique.

Note: If using sunlight for exposing of plates the process works best on a clear day with no or little clouds. Generally best results are achieved using mid day direct sunlight. UV rays can vary depending in which part of the world you reside and also the time of year. For example where I live in the Northern Hemisphere the UV light during the winter months would be greatly reduced in comparison to the summer season, so exposure using this method would require a greater increase in exposure time.

You could make a single exposure of the artwork but really that works best for achieving high contrast images and prints where tonal variation is not an issue.

It all begins by make sure your artwork is properly set flush against the plate surface. For this one must use a flat even piece of board, set a piece of foam or black felt on top of this, then the plate. The opaque artwork can be on a surface that will allow light through such as a transparency, acetate, frosted drafting film, glass, etc...). This is then set on top of the plate and a piece of clean glass is spring clamped to the board to create a tight bond for exposure purposes. Once an exposure is made the plate is developed by immersing into lukewarm water and gently scrubbing away the polymer with a soft bristle brush. Only the areas that were opaque will wash out leaving open channels in the polymer surface in which ink can be contained. The plate is then blotted dry and exposed as is one more time to UV light to harden (cure) the polymer. Ink can then be applied and wiped to the surface in the same manner as a traditional acid bit plate that would inked. The plate is then ready to have a sheet of damp printmaking paper plus three layers of wood felt blankets placed over top and passed through the rollers of an etching press, thereby transferring the inked plate impression into the paper.






photo 1




Photo 2



Photo #1 shows my home-made UV exposure box. It is composed of 4 banks of blue bulb blacklights and reflector ballasts (photo #3). These were purchased from Walmart for around $65 CDN. The wood and screws plus the power bar ran me around another $25 CDN so was able to build the entire unit for well under $100. To purchase a premade unit from Dick Blick or Solarplate.com will run you around $350 USD plus your shipping.



My home made exposure box will allow for plate size up to 28 cm x 35.5 cm (11 x 14 inches). So far my exposures have been very good using it. No more waiting for sunny days outdoors.
This unit seems to work quite well and the bulbs emit the proper wave length of UV (around 360 nm) which is comprable to natural sunlight UV spectrum.

In photo #2 you will notice that holes have been drilled in the lid on one end to allow for the power cords from each unit.
Each ballast is suspended (secured with wood screws) to the underside of the lid (photo #3). The box itself sits on four wooden tea boxes for corner legs about 7.6 cm (3 inches) above the table surface. This combined with the distance of the bulbs underneath the box will give a height ratio of maybe 11 - 12.5 cm (4.5 - 5 inches ) above the plate when it is exposing. I generally set a piece black paper underneath the unit first and then tape sections of black blockout paper (bristol board) around the perimeter of the unit when I expose a plate.




photo 3




A plate is usually exposed for 3 - 4 minutes each for the aquatint screen and positive and then developed in the water tray.


Photo #4 shows the plate being cured after the washout developing of the image. Notice how the UV causes the orange polymer to glow like gold. This thin polymer surface is fused onto a support base of thin steel. The plate can be cut to different sizes by using a sharp paper cutter blade or by running several passes of a sharp utility knife blade along the edge of a cork backed metal ruler. You cut through the coating and into the metal and then snap the plate off by bending it down and up using the edge of a counter or tabletop.




photo 4



Here is a colour digital photo I took of a section of fallen old growth white pine. (photo #5)


photo 5
Photo #6 shows the result of the exposure of the grayscale transparency version of this photo with an aquatint. The plate was exposed using the double exposure technique at 4 min for the aquatint screen and 4 min for the positive. Then it was immersed and scrubbed in water, dried with warm air and cured with an additonal 10 min. UV exposure.



photo 6

Photo #7 shows a print on paper (in sepia) taken off the plate after it has ink wiped into the recessed line and the surface polished with tissue paper.





photo 7




Photo #8 is another example of a photo image exposed onto a solar plate.



photo 8




Photo #9 is the resulting print on paper from that plate.






photo 9

10 comments:

  1. Cool stuff.

    Does the plate need to be uncovered in a dark room in order to prevent a premature and muddying UV exposure?

    Nice web site.

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  2. very good thanks for showing I wonder about your exposure times are they a good average?

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  3. In the case of pre-exposure I prepare the positive and aquatint on the plates under LED light (puck type) as this doesn't emit any UV.
    You don't want to expose it to direct UV sources such as sunlight, incandescent bulbs or compact flourescent light.
    I have found that best results are produced between 3 to 4 minutes for length of exposure in the home made unit. This may also be due to the small plate size and the distance of UV emitting bulbs in relation to the plate.

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  4. Hi. Lovely, lovely work. If I want to just produce a relief block, how long should I expose the photopolymer plate to my acetate positive for? I have access to a UV exposure unit.

    If i do not need the aquatint screen, would I just expose the psotive and plate for 10 mins and then wash..... etc....

    I would like the maximum sharpness I can get...... think of very graphic bold lines like 60s pop art, but not the really fine lines, much more geometric. etc etc. ANy help would be fantastic!

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  5. you won't require an aquatint screen to create a relief plate. I usually expose mine for 3.5 to 4 min duration and get very crisp line and good washout of (non-printing surface) negative area down to the plate surface.

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  6. What a great post! I am also looking into this. Less expensive than solar plates or relief polymer plates, may be to make a plate with dry photopolymer film as is used for etching electronic circuit boards. The film is very inexpensive, and can also adhere to a steel plate, and be etched with CuSo4 or NaCl solutions. A cold rolled 16gauge steel relief plate may allow for less cost, longer plate life, a deeper bite, limited embossing, faster inking. I think relief printing affords easier registration with dry, or near dry printing paper. Low cost and easier registration means it is easier to make larger multiple colored plates, and also use better registered stencils.
    Also, if one can not afford a high priced aquatint screen, it may be able to make one with a simple airbrush or two on acetate or Mylar film..experiment by spraying from a distance a mist of fine opaque dots on the film.
    Thanks again for making such a great post.

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  7. Thanks for all the good information! Do you think a 300W sunlamp would work with solar plates? Your images turned out beautifully, and wanted to let you know that if you print on dry Arches 88 archival printmaking paper, you get stunning images.

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    1. thanks for tip about Arches 88. I have used this paper for screen and relief printing. Unfortunately if I were to print solar plate onto it I don't think I would be able to add watercolour. I remember experimenting with this once before (watercolour addition) and it was immediately absorbed by the paper and bled out. However if I carefully wiped colour etching ink on the plate that would probably work well.

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  8. Thanks for all this very good information. Do you think a 300W sunlamp would work as a uv source? What kind of a brush are you using for the water wash? Also, printing on dry Arches 88 paper produces great prints.

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    Replies
    1. sorry took a long time to respond to your question here. Perhaps you have already figured out a system but I believe you need a wide area of UV light exposure for best results. If your positive and plate are small you could try the 300 W lamp...however I have only ever used black light and natural sunlight for my exposures. I use a soft bristle toothbrush for the scrub process during the water wash. I also found blotting quickly with newsprint and then a quick blast of warm air really helps dry the plate evenly with no water spot damage. I have used Arches 88 for single monochromatic prints or if one is using dry media to apply hand colouring

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