There are a variety of styles of screen printing frames available.
At the low end of the spectrum are wooden frames. You can buy wooden frames, or if you have basic woodworking skills, and a little bit of equipment, you can make your own. If you are just starting out, you should just buy one or two. I bought my wooden screens at Dick Blick. The benefits of wood screens is they are relatively cheap. Some of the negatives are that they can warp over time, since you are going to be running them under water often. The better wooden frames have jointed corners. The cheaper ones have 45 degree mitered corners, with little metal fasteners. The mesh is usually held in place by cord pressed into a slot. The mesh can sometimes come loose if the cord slips. This can be fixed by removing the cord, stretching the mesh over the frame, and stapling the mesh in place.
A step up from wooden frames are aluminum frames. Aluminum frames have welded corners, and won’t warp. But aluminum frames are more expensive than wooden frames. But they will last longer than wooden frames. The mesh is permanently glued to the frame.
The best frames you can buy are Newman Roller Frames. These are also the most expensive. These allow you to retension the mesh by tightening the rollers. I have read about the process of tensioning the mesh on one of these, and it is quite involved. If you are a hobbyist, or not really planning to be printing lots of shirts regularly, these are probably overkill. The mesh can be replaced on a roller frame if it is damaged, or to use a different mesh count.
When buying frames, you also need to decide on what kind of mesh you want to use. This is because the frame usually come mounted on frames. I use 110 monofilament mesh. Mesh with higher numbers will allow more detail. Mesh with lower numbers works better from printing light colors on dark shirts. 110 is a nice middle ground general purpose mesh.
You will also need to determine the size of the frames you want to use. The larger the size of the frame, the more they will likely cost.
After you have coated your screen with photo emulsion, exposed the screen, screen printed with the screen, and then cleaned it, you may want to remove the photo emulsion so you can reuse the screen.
I had read that you can use bleach. So I bought a gallon of bleach for a dollar at the local grocery store. After I had washed away the leftover ink using warm water, I brushed on bleach, and let it sit for a while, and scrubbed it with a nylon bristle brush. Then I sprayed the screen with warm water. Some of the emulsion had been removed. I reapplied the bleach, scrubbed, waited, sprayed, and more came off. After about four applications, the screen was pretty much cleared. Basically, it was a lot of work, and used a lot of bleach.
I decided to try stencil remover. The local art supply store was out, so I drove to Syracuse, and bought some over there (combining the trip with a book hunting expedition). The quart bottle was relatively more expensive than bleach. I hoped it worked.
I poured just a little of the stencil remover on the screen, and used the nylon bristle paint brush to spread it around, I scrubbed lightly with a nylon bristle scrub brush, and then wait a few minutes. When I sprayed the screen, almost all of the emulsion was removed. Just a dab more stencil remover, and the rest was gone too. Compared to bleach, this stuff was magic.
The stencil remover hands down beat the bleach. I have also read that bleach is harsher on the screens, and will shorten their life. As the old saying goes, use the right tool for the job.
When exposing a screen, exposure time varies depending on the type of light, whether there is reflector, distance from the screen, bulb wattage, etc. And if you don’t expose a screen long enough, the image gets washed away. If you expose a screen too long, you will start to lose fine detail of the image.
What kind of light to use? I currently use a 250 watt halogen work light with the UV filter glass, and safety cage removed (you assume all risks if you remove your glass and/or cage from your halogen light). In the past, I have used a 75 watt incandescent bulb in a reflector with a clamp. Whatever you use, make sure you have some way of clamping it, or mounting it above the frame for an extended period of time.
Before you expose real work, you want to run a test to find the best exposure time. First take the light you have, and place it above a frame. You want to place it high enough that the whole screen gets equally exposed, but not so high that the screens will take forever to expose. If you use a spot light, it might focus too much light on the center of the screen, and not as much on the corners. This would lead to uneven exposure.
Once you have the light and placement figured out, we need to figure out some rough times. In the Speedball manual they give some times for a 150W clear incandescent bulb:
Screen size, bulb height, exposure time
8×10, 12 inches, 45 minutes
10×14, 12 inches, 45 minutes
12×18, 15 inches, 74 minutes
16×20, 17 inches, 92 minutes
18×20, 17 inches, 92 minutes
The higher the bulb is above the screen, the longer it needs to be exposed. If the wattage of the bulb is lower, you need to exposure it longer.
When I used the 75 watt incandescent bulb at 17 inches, I had to adjust the time. Since the wattage was half of the 150 watt recommended bulb, I simply doubled the exposure time. This worked fine.
When I started using a 250 watt halogen light at 23 inches, I needed to refigure the exposure time. Since the 250 watt halogen light was brighter than a 150 watt incandescent light. A halogen bulb puts out more light than an equivalent wattage incadescent bulb. So the exposure time would need to drop. And since I was raising the light higher above the screen, the exposure time would need to increase.
So not knowing the best time for exposure, I had to experiment. I didn’t want to expose screen after screen until I got it right.
This is what I did:
I coated a screen the usual way. I printed a transparency with numbers from 10 to 90 in increments of 5. With the light set up, I placed the screen under the light to be exposed. I had a stop watch going. After 5 minutes, I covered the 5 with an opaque piece of paper. After 10 minutes, I also covered the 10. I did this until all of the numbers were covered. Then I washed out the screen. The lowest numbers that were distinctly printed gave me the correct exposure time. The numbers below 40 all got washed away. 50 looked okay, but 60 looked better. So I used 60 minutes as an exposure time for my 250 watt halogen light (without UV filter glass) at 23 inches. With experience, I have since lowered the exposure time to 45-50 minutes.
In screen printing, you might want to print something larger than will print on a single piece of 8 1/2 x 11 inch paper. But how to do it? There is software out there specifically designed to print stuff like this. It will break up the images, and print it in sections. But I am cheap. I didn’t want to pay $20 or more for a program that does nothing more than this. I started playing with some of the programs that I alreayd had. I couldn’t do it with Adobe Photoshop. It might be able to do it, but I couldn’t figure it out. Maybe a newer version has a feature for it (I am using version 3.5). I suppose I could just manually break the image up into smaller pieces, and print them on the transparencies. I tried Microsoft Word, but couldn’t get it to do it.
That I found the solution. Microsoft Excel!
Simply open Excel. Go to the Insert menu option, and select Picture. It will give you another menu, so select From File. A browse box will pop up, so use this to select the image that you want to print. This will insert your image into a single spreadsheet cell. Right-click on the image, and choose Format Picture. Under the Size tab, you will find the ability to adjust the size of your image. Make sure you have "Lock aspect ratio" checked, or it might distort your image.
Now you can print your image. Excel will automatically print the whole thing, using multiple sheets if needed. You can print whole banners if you want. I have used Excel to print a poster size image that was 5 pages wide, and 6 pages tall. So it was 30 pages in all. I just had to tape them all together.
So for screen printing, you would just print your image onto transparencies, and then tape the transparencies together (using transparent tape) into one contiguous image.
I generally make my own screen printing art using Adobe Photoshop. On my Screen Printing Artwork page, I show you how I made one piece of art.
Graphic art for screen printers is widely available. Lot of different things can be used. You can use clip art, photographs, whatever.
You can make your own art using any computer graphics program you have available. The paint program that comes with Windows can be used. My own choice is an old version of Adobe Photoshop. I love this software, and the use of layers allows cool images to be easily made. I have also used Microsoft Word to make text art.
There are plenty of sources of clip art that can be used. If you are planning on makng shirts to sell, make sure you have the rights to use the art for that purpose. If you are making a shirt for yourself, you probably shouldn’t have any problems unless you use some trademarked image, and happen to draw the attention and tick off the trademark owner. I have read this has happened with people using Disney images.
If you find single color images, then you are all set. If the images are multiple colors, then you will need color separation software. Color separation can be costly, involved, and is not for beginners. It would also require the use of a multi-color screen printing press in order to print it.
You can create screen printing art from photographs. If you want to print the images in multi-color, again it would require color separation software, and a multi-color printing press.
Another less expensive option is convert the photograph to a halftone image. Halftone images are like those black and white images that you see in newspapers. They are made up of little dots of different sizes. This can be done using Adobe Photoshop.
And even another way to print a photograph is to use a high contrast photograph, and convert it to two color. This is trickier to do. The photograph needs to have the right balance of dark and light shading, and then it stills requires a lot of exerimentation to get it to look good.
When printing black and white photographs, it works best if you are printing white on a black shirt, or black on a white shirt. If printing white on a black shirt, you would initial print a positive image (the black parts are printed black). If printing black on a white shirt, you would need to print the image as a negative. The white parts print as black.