Fabric Printing Part 3: Line Quality and Silkscreening at the Textile Center at the July MCBA Visual Journal Meeting.

July 30, 2010

Some dos and don’ts for making silkscreens with the Thermofax; and how to have custom screens made for you at the Textile Center.

100719FabricMaster Left: The original toner copy I used to make my screen. In Adobe Photoshop I layered several sketches from various journals. Some sketches were pen and fine line, other sketches were made with pencil and have a rougher line. After the layers overlapped as desired I saved the flattened image in grayscale and adjusted the contrast. Next I saved the image as a bitmap, selecting diffusion dither. I find that this creates a printout that captures the tone and texture of the original line work the best. You can see tones in the eye of the dog for instance, mimicking the pencil work. Diffusion dither will cause dots to appear in some “white” areas if your image is not sufficiently cleaned up. You can fix this by readjusting your contrast before applying the diffusion dither. Alternately you can go in and erase any fine dots that bother you and which you don’t want to print. You can see dots in this image in the white area in the quick puffin sketch at the bottom. If you save your image as a grayscale image and print that out as a toner copy or print to use in any of the heat transfer techniques you will see the halftone screen pattern in your image and not all printing methods will capture the subtlety needed to print the resultant image. Alternately you could take your artwork into Adobe Illustrator and turn your line work into vector art. A number of factors will determine the success of this process, but the end result will be infinitely scaleable.

At the July 19th meeting of the MCBA Visual Journal Collective I brought the carbon toner printout shown at the left. I follow the procedure described in the caption all the time when making prints with the Print Gocco (which also uses carbon toner copies and heat to create screens for printing; and yes I have a few screens left!). I knew that the screening material used in the Thermofax process was made by Riso, the company that used to make the Print Gocco. I wanted to see if it had similar tolerances. The layered sketches in my image were selected to give me a sense of the line quality tolerances of this process.

At the beginning of the meeting the presenter, Karen Wallach, suggested that everyone use artwork with thick line work for best results. See my Friday, July 23 post for the clean crisp results achieved by those who opted to redraw their artwork with darker lines. Don’t give up on the process, just be sure you think about your line quality. I decided that I’d go ahead with my plan and see what came out.

The screen burned well. However, in the eye areas of the dog and ostrich where the darkest darks are located blocked up. I could have lessened this effect by using a lighter copy, or by taking a copy and doctoring it with white out. I didn’t do either, but keep in mind that you do have those options (as well as redrawing your art with thicker lines).

100719FabricLIGHT Left: After a clogged first print (no longer with me, see the text) I tried light pressure still on the towel padding. It was clear to see that there was no amount of light pressure that would prevent the clogging in the darkest areas. However I continued to experiment with pressure on the screen to get a sense of how to print the lighter lines. (All my samples were printed on cotton fabric.)

When I went to print my screen, I found that the screen allowed way too much ink through, even with only medium pressure. I was working on folded towels as suggested for a starting point. (My original print was left with Karen, but it was way more “clogged” than my other samples here.)

After printing one iteration too dark and another too light I experimented with pressure by removing my towel padding and printing with light to medium pressure. My last example below is printed in that way. I found that I had the most line quality control with these fine lines when I printed without any towel padding, directly on the table surface (which was covered with plastic for protection).

100719FabricPatternedLeft: a medium pressure print on patterned fabric, using only the table surface, no padding.

At that point I stopped my printing experiments, having learned what I could from my own screen, and went off to help Janice Paranto print her jade plant sketch. (It helps if you have a printing buddy to hold down your fabric as you peel the screen off.)

I don’t have any photos or scans of her image, but it was a sketch that had fairly fine lines, but thicker than those in my sketch. Her lines were also of an even weight throughout the image. The main issue with printing Janice’s screen was that she had gone right to the edge of the screen with her image size and it made the outline border of her sketch difficult to print consistently, not because the line weight wasn’t sufficiently thick and clean, but because it was located right at the edge of the live area. Greater familiarity with the process will allow Janice to plan future screens to avoid this issue. She nevertheless managed to get several very crisp prints of her lovely sketch.

We also learned, while Janice was printing, the importance of maintaining a level sweep down to the bottom of the screen. If you flip your wrist at the end of that process you can actually force the bead of ink you’ve been pushing with the squeegee, out under the screen into a blot. Practice on scrap fabric and watch how you are maintaining the angle of your hand as you squeegee.

People printing with gold metallic paints had the best luck with extremely thick-lined artwork. Karen explained that the metallic paints are thicker because of the metallic pigments and getting them through the screens can be more problematic, unless you have thick-lined artwork.

Karen also suggested that when changing ink colors you add the new color and essentially “clean” the screen as you print, making intermediate prints where the colors are blended, until the first color is no longer visible. Washing the screen would not allow enough time for drying in our session. I also think there was something about the tape on the screen getting worn with repeated washings, but I may have misheard.

By now you’ve seen the neat prints that people at the meeting made, and you have some ideas of what not to do. You’re eager to try this printing method yourself—it’s as simple as sending a carbon toner copy of your artwork to the Textile Center.

You can also send a black and white drawing or ink jet copy. The Textile Center will make a carbon toner copy for you, included in their screen prices.

Screen sizes and cost are: 9 x 12 inches (with a live area of 8 x 11 inches) for $12; 5 x 7 inches (with a live area of 4 x 6 inches) for $8.50; and 4 x 6 inches (with a live area of 3 x 5 inches) for $5.50. There is usually a two-day turnaround and you can schedule a pick up. You will receive a completed, mounted screen. (The Textile Center will also do mail order screens if you don’t live in the area, or if you live in the area but can’t get back to pick it up—check with them for postal costs.)

Be sure that you keep your art well within the live area stated for each screen size. The person making the screen will need that extra space on the sides for duct tape overhang which will hold your screen in the frame. Also you want space on the sides between your image and the duct tape to make it easier (and possible) to get all the areas of your design printed. (Lines that fall near the duct tape are very difficult to print successfully.)

All you need at home to print is some plastic to protect your table, a bath towel for padding (which you may end up not using—but you’ll need to experiment); a squeegee that is the exact width of the screen opening—you want to be able to swipe the ink in one motion; and inks. Acrylic fabric silkscreening inks are available at most art supply stores (like Blick). Karen pointed out that you can use any paint or ink that will push through the holes of the screen so feel free to experiment to find out what works best for you and gives you the look you like. Karen recommended silkscreeing with foiling glue and then when it is dry, applying gold foil to your design!

Be sure to have all your fabric and supplies ready to print when you get the ink out. You want to keep moving fresh ink through your screen. Acrylics dry quickly so you don’t want the screen to sit with ink on it while you cut more fabric. Wash your screen with water as soon as you have completed your session. Don’t soak the screen or you will dislodge the duct tape. If you take care of your screen there is no reason you should not get hundreds of prints out of it!

When your prints on fabric are dry, remember to heat set them per the ink’s instructions, with an iron. Now you’ve got a washable print to add to a quilt or a washable t-shirt, table runner, etc.

Remember, this process can also be done on paper. 

Why not have a printing party with a group of friends? Get your group's artwork together one evening— sizing it, adjusting the line quality, etc. (Or have people do this on their own.) When all the artwork is ready, send it in or deliver it to the Textile Center to have screens made. This way you can share one pick up trip or the postage costs. When the screens come back have a printing party where you pool ink costs and share fabric. Make an extra print of each screen on inexpensive cotton cut to a uniform size, to give to the participants as a reminder of the fun evening. You could even make a portfolio (perhaps at another evening get-together) to contain your record prints from each printer.

Speaking of record prints—be sure to keep your first test prints along with notes about what worked and what didn’t work. This will help you the next time you set up to silkscreen.

Making silkscreens with the Thermofax is something to look into!

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