It's important that your screen doesn't lay directly on your printing surface. You want a good off contact, about 1/16"-1/8". The screen needs to clear after you bring the squeegee across. The screen should pop up slightly.
I came across some problems during my last screen printing session. Hopefully my dilemmas can help someone else ...
This is what the ink looks like on fabric with bad off contact. The screens stick to the fabric. When you peel it off, it looks like this ... (pic below) ... thick and has peaks.
Here is a pic of good off contact ... (pic below) ... smooth, flat ink.
I thought I had good off contact, but as you can see, I didn't. Not sure what happened. Ever print was different. The screen would clear good in some spots but not well in others. This is my first time printing with a very large screen. On my next try, I'll raise the screen a little higher.
Screen printing, one color, part 1 - This video is about 10 minutes long. The importance of off contact is covered towards the end. I found some really good tips throughout the whole video.
UPDATE: I do not believe that this technique is the only way, this is my experience ...
I have noticed that with thinner inks and paper, maintaining off contact is not as important as with thicker inks and fabric. On paper, when I have used thinner inks, I was able to achieve flat smooth print by laying the screen directly onto paper. Not so with thicker inks and fabric.
Plus side to off contact ... When not hinged, I can move my screen around without it touching the printing surface. Very helpful for printing repeat patterns (lining up) and laying the screen down.