Sunday, August 30, 2009

Making Multicolored Prints with a Thermofax Screen

One of the most interesting ways that I've found to use a thermofax screen is to make multicolored images using water-soluble crayons, such as Caran D'Ache. I find these colorful one-of-a-kind prints both versatile and appealing, whether used on their own or in combination with other screen-printed fabrics. The pomegranate above is a simple example of the technique -- with both the red fruit and the green leaves printed at the same time.

The process depends on using a polymer based medium to carry the water-soluble pigment onto the fabric and, in drying, to bind the image to the cloth surface -- after appropriate heat- or time-setting. I've used various kinds of polymer media with the process -- transparent fabric screen ink "extender," Golden® or other brands of gel medium, both glossy and matt, and the newer Golden® open medium, which does not dry as quickly in the screen as the straight acrylic mediums do.

Essentially, one colors the open areas of the thermofax (this works with traditional screens, as well) with the water soluble crayons, coat the screen with a generous portion of medium, letting it sit a SHORT time, then screen-printing as usual (a plastic scraper works better, I think, than a foam roller). The first print is often partial or broken in line, since the crayon can act as a partial resist in the screen, the second and third are usually quite interesting; the color starts to fade and blend with the subsequent prints. I often recolor the screen without cleaning it, working quickly to beat the drying process, and that can lead to interesting results, as well.

Because you are using a relatively heavy medium, this process is best for substantial fabrics and for usages where some change of hand won't be disturbing or distracting to your end result. It doesn't work well on silk scarves for example, but is great for art quilt and mixed media work.

Coming up this fall, I'll be teaching a full-day workshop on this technique at the International Quilt Festival in Houston, Thursday, Oct. 15 in the Mixed Media classroom and I'll be demonstrating the process at one of the Mixed Media Miscellany samplers, Saturday, 10-noon. There will be lots of different polymer media to try out, some different kinds of crayons to test, hints for the best designs and lots of demo and hands-on explorations. For more information, see

Monday, August 24, 2009


The problem with having plastic not completely removed by toner can be caused by the toner
on the photocopy not being fused completely enough to the paper. The plastic bonds to the
toner but the plastic can pull the toner off onto the screen if there is too dark a copy or if the
paper is not dry enough. In the future, you may find you get better results making lighter
copies, although this seems counter intuitive. I found many posts about this on the print
gocco yahoo list, which uses the same process with flash bulbs and 100 mesh. There is
a Riso product called "clean up paper" that is recommended to solve this. (I have not seen
clean up paper in the Welsh catalog but perhaps they know about it. The info about it was
posted by Simon, a Riso distributor in AU)

It is even more important not to clog mesh and to cut a clean screen with the fine 100 mesh
print gocco screens. I found I got better results after I realized what was happening. I made
sure to dry the paper well with hairdryer or iron, and on very dark copies, I ironed them from
the back on another piece of bond to make sure any toner that was left was well bonded to
my copy I planned to run through the thermofax, leaving any excess toner on the blotter sheet.
Repeat with clean paper until your blotter sheet is clean.
(I replied to Caryl's inquiry on dyerslist but I hope others might find these tips useful here)

Enid Adams-Surface Design Studios


Before I owned a thermofax, I had purchased a box of 20 stencils, not fully realizing the equipment needed to develop them. They stayed in a zip lock bag in the refrigerator until I found out about mail order imaging services. While the stencils seemed OK at the time the screens were burned. Over time, I ended up with many sheets of thermofax stencil that had started to separate (some imaged, some not) and thought all was lost. Trying to reheat them with an iron proved disasterous, causing bubbles and distortion, even with a teflon pressing sheet. Still I am such a packrat I somehow didn't throw them all out.

After I finally obtained a thermofax at a government auction, I found I could run the stencils back through the machine without a photocopy, and refuse the plastic to the mesh. For those that had been burned, and their paper backing removed, I was able to sandwich them in a carrier and have them refuse relatively well without distortion. They did not become the long lasting stencils they might have been if they had been stored properly for not too long, but they were not a complete waste, and gave me tools to work with immediately. I used screen blockout on any edges that needed reinforcing.

I found I needed to complete the process of printing with these designs. Sometimes seizing the moment of inspiration and motivation is what is most important, and I had a chance to proof the design and make adjustments in the next one. I am also trying to use what I have. Now I am ready to move on to more evolved imagery for the next screens, being older and wiser, with a better understanding of what works both visually and technically.

Enid Adams-Surface Design Studios

Sunday, August 23, 2009

U.S. Suppliers and Services

Per the conversation on transparency machine repair, please note that the sources listed below have all been known to sell and repair transparency makers. The first company listed is Welsh Products, where Riso Film, Frames and Carbon pens can also be purchased.

If you are in the market for a machine, you may want to ask the seller the weight of the model for sale. They vary from 24 - 46 lbs. for the models that are not portable. Twenty pounds can make a big difference if you're moving it around.

Should you know of a reliable repair business, please let us know and we can add the names and info to this list.


CA: Welsh Products 800-745-3255

Machines, Riso Film, tape and spare parts

CA: Image Works 888-789-1917

Repair and spare parts

CA: Roy White 916-481-2450

Repair and spare parts

Gil White Repair and spare parts 909-790-9588

IL: Duplicators & Visuals John Messaris

Available April - October

Pick up only in Chicago 312-226-1331

Repair and spare parts 773-561-7330

NY: GC Service George Cromas 718-951-8293

COD shipping only Repair and spare parts

PA: Bob Haller Svc 412-364-4340

and Sales Repair and spare parts

TX: McIntosh AV 888-449-6893

Repair and spare parts

FL: Jim Leasure

Repair and spare parts

Friday, August 21, 2009

Trouble with Burning the Screen

I purchased my Thermofax about 5 years ago from a technician in Chicago,and sadly, it sat on a shelf for most of the time since. I got it out to play with, and have very dark photocopied designs with which to make my screen. The nice folks at Welsh tell me that there should be no plastic left in the image area, only the base mesh. That is not what is happening; on most of the screens, I would guess that at least 50% of the plastic is left, but they seem to work... Friends who have used my machine tell me that
the screens made on my machine do not differ significantly from those made on other machines. I do have a couple of screens made several years ago, I think in a class, that appear clean in the image area.

When I run the copy/film through, the light comes on; the machine is set for the slowest run-thru speed, and the screen is warm when it exits the machine. Running it through a second time does not seem to make a difference.

I would appreciate comments, suggestions and knowing if your screens burn out completely.

Caryl Hancock, Indianapolis

Caryl, my screens burn all the way through. Is it possible that you are not using a photocopier with carbon toner? If you go to a commercial place like Kinko's or Staples to use their copier, very often they have digital copiers that don't have as much carbon. And the people who work there don't know the difference, so even if you ask, you won't necessarily get the right answer. I would suggest you try to find a different photocopier and experiment with it (older ones are the best). Maybe your public library has an ancient one that would be good for your purposes.

A true laser printer (i.e. - carbon toner, not an all-in-one digital printer) will do the trick and I have been told that believe it or not, the HP ink jet black ink has enough carbon in it to cu a screen - so that's something else you can try.

Good luck hunting and let us know how you make out.

One other thought if it turns out not to be the copier you're using - maybe your lamp just is on its way out and isn't hot enough. But try the other options first.


Wednesday, August 19, 2009

Thermofax Basics

The thermofax machine is a relatively simple machine. It features an opening approximately 10" wide (this varies by machine type) into which the thermofax film is inserted. The film is layered face to face with a photocopied design. The photocopy must be created using a carbon toner system. The film/photocopy combination passes through the machine in less than 30 seconds and is exposed to a very hot, bright light inside the machine, which melts the plastic coating of the film onto the carbon toner. When the paper/film sandwich exits the machine and the paper is pulled off, the image transfers to the film and is ready to use. No other method of generating a screen is so immediate.

Believe it or not, thermofax machines are still discovered in the storage warehouses of schools and businesses, because they were discarded when photocopiers were introduced. Older machines are also available through Internet auction houses on a regular basis. New machines can be purchased from Welsh Products and from Guenther Panenka in Munich, Germany. Supplies for the machines are available from Welsh and also from Dick Blick, and for anyone who isn’t interested in purchasing a machine, numerous services exist to generate Thermofax screens from individual designs. (see the sidebar on this blog)

Here’s How it Works:

1. Photocopy original artwork — clip art, black and white drawings, etc. — onto a carbon toner copy. Most commercial copiers use carbon toner systems. Inkjet and other types of computer printers are not carbon toner systems.
Tip: If the copy is NOT a carbon toner copy it will be evident immediately: the copy won’t bond to the Thermofax film when the combination is inserted into the machine.

2. Cut Thermofax film large enough to accommodate the photocopy image and large enough to cover the opening on the plastic frame. The film must extend onto the plastic frame around the opening so it can be properly taped.
Tip: Reduce the photocopy image slightly if it extends too close to the edge
of the opening on the frame. Otherwise, when the film is taped to the plastic frame the outside edges of the design will be lost. It’s a good idea to leave 1" of space around the design so there is room for tape later.

3. Align the plastic film, shiny side facing the photocopy. It seems to work best to put the film on top as the sandwich is run through the machine. The toner design MUST face the shiny side of the Thermofax film. Put the film/copy sandwich inside an acetate carrier or use an 11” x 14” piece of paper as a guide. Fold one end of the paper over about 2” and secure the sandwich at the edge of the paper prior to inserting it into the machine. The carrier keeps the two layers together, and properly aligned.

4. Insert the carrier into the opening in the Thermofax machine. The machine’s roller helps pull the carrier into the machine. The light inside flashes on, and then the carrier exits through a slot at the base of the machine.

5. Open the carrier and remove the copy/ film sandwich. The carbon should be bonded to the plastic surface of the film. Separate the film and photocopy by peeling them apart. Separating the copy from the film pulls the plastic off and opens the design to make printing possible.

6. Tape the Thermofax film to a plastic frame. Use duct tape for permanency. Cut a piece of duct tape the length of one side of the film. Tape the film over the inside opening of the plastic frame. Position the tape so that it passes onto the mesh along the frame edge, which helps keep the squeegee from cutting the film accidentally during printing.

7. Tape all four sides of the film to the plastic frame using the same method. Extend tape over the inner edge of the frame and onto the film about ½" to protect the film during printing. When the screen is taped and the tape cures (approximately 24 hours) the screen is ready to use.

8. After printing wash it gently with a sponge and cool water and the screen should last for hundreds of printings.

A thermofax screen doesn’t have a right or wrong side. The side with plastic film is more fragile than the polyester mesh side, so it might be a good idea to print with the plastic side against the cloth most of the time, but if you need a right and a left version of the design you can clean the screen after printing one side, allow it to dry, and then flip it to print the other side. Just be careful when rinsing, and use a soft sponge instead of a scrub brush.

Film gets old and begins to degrade. On the roll this is indicated if the unused film turns color or gets brittle. On a screen degrading is indicated if the film begins to separate from the mesh before, during or after printing. Degrading can’t be stopped. Cut your losses and make a new screen. Share a roll if you are purchasing a new one. Two people (or four) usually go through a roll of mesh much faster than one person can do.

Carbon toner copies aren’t the only way to make a Thermofax. Carbon pencils and pens work too. Experiment with tools you have on hand, or check an art supply catalogue for carbon based tools.

One of the biggest complaints about Thermofaxes is paint drying in the mesh and ruining the screen. This is frequently operator failure more than it is the paint. Screening goes smoothly if paint is always replenished as the printing proceeds. If the paint being pulled across the screen is fresh from the bottle it will always retain enough moisture to keep the screen open. Too many passes of paint that’s drying out is the main reason screens fail and require re-screening. You can always put paint back, so use slightly more than you think you need. Exception to the rule: dry climates. Add a retarder to the paint to keep it from drying so quickly. (Available from textile paint suppliers.)

Buying a Thermofax Machine

There is one machine you have to be careful about purchasing among all the old reliable thermofax transparency makers - Model no. 45EGA. After its manufacture it became apparent that is was a fire hazard if left “as is”. Many models were retrofitted with an adaptor, by the various 3M maintenance guys across the country, so some of them work fine. One of my students bought one on line and it began smoking as soon as she began processing her screen. She contacted Welsh Products (a great resource for machines and supplies) and they explained that they couldn't repair it since even after being repaired it was still a known fire hazard. The seller in Texas refused return or refund until contacted by Welsh. They explained the situation, and then the seller agreed to a return.

I met someone who bought a machine on Ebay and the seller sent it with newspaper as packing material. It was smashed to smithereens on the inside by the time it reached her. Be sure to establish that the packing will be thorough allowing no room for shifting en route to you.

Some sellers on Ebay claim that machines made later - the 4500 series - have a wider imaging area. This is false. The bulb on the inside is the same size, but the feed slot is wider to allow for occasional lopsided feeding or larger documents. In the older machines with a narrow slot, papers and film that are fed in askew will sometimes get stuck, causing the carrier or film or paper to burn, and requiring the replacement of the belt.

Don't forget to check local schools, hospitals, and other places that might have old audio/visual closets. You may be able to find one that's more affordable than those on Ebay

from Maggie Weiss