Basic Screen Printing Techniques: For the purpose of this article we will assume you have a screen made using the correct mesh. No, 110 (43cm) monofilament doesn’t work for all job. You need to use the right mesh count to have a good print. Although mesh count is an entire topic, for now let’s assume you are doing a simple three-color print on a light shirt.
I would use a 160 (61cm) to 180 (70cm) monofilament mesh with either very well made wood frames that have been purchased with the fabric already attached (prestretched) OR I would use a metal retention able silkscreen that I had brought to the proper tension a couple of times to get the fabric very tight. I choose the 160 to 180 because I want to lay down a little less ink since this is a multi-color job AND in doing so I will not have to flash cure between colors. In fact I can print this job wet-ink-on-wet-ink. Trust me!
I would too have used a dual-cure photopolymer emulsion as my stencil since they can be used with simply a single coat on each side and they hold up well, yet reclaim easily.
Square the Screen to the Shirt board the screen needs to be placed on the press and squared to the shirt board. This is as simple as placing a t-square under the frame and looking through the silkscreen to square the image on the frame to the edge of the board. Now when you create a print it will be straight to the board.
Color Print Sequence
When printing multi-color prints on light shirts you generally print the lightest color to darkest color OR the smallest print area to the largest area. This sequence, along with the right ink viscosity will help minimize ink picking up on the silkscreen bottoms. This is called build-up and is a common problem in color printing. The easiest way to line-up screens on a color print is to make a print of the outline or main color and just line-up the other screens to the print. Sure you may get a little ink on the bottom of the silkscreen but guess what? It will wipe right off.
Adjust the Off-Contact Distance
The screen MUST be set to sit slightly off the shirt-board. This is called off-contact printing and is how all good printing is done. a few presses have adjustments for this. Others will need to have the silkscreen shimmed from underneath. Either way, you may need to put a thin piece of cardboard under the edge of the frame so it will hit the shirt-board as the silkscreen comes down. This may seem unorthodox, but again, trust me. You need to keep the silkscreen from 1/16″ to 1/8″ off the shirt and no matter how well made a manual press is, the tip of the silkscreen is going to move downward when you get to the end of the stroke and nothing is going to keep it off the board but a just shim.
This is one area where there is a lot of confusion. The ink manufacturer told you that the stuff in the can was “Ready for Use” (RFU). That means just slop it in the silkscreen and “pump up” to create a print. RFU is one of the greatest lies ever told.