Screen Printing: Everything you ever needed to know
Welcome! The Basics Hello my wonderful and good-looking friends, welcome to the strange and wonderful world of screen printing. There is a lot to explain to you so I will keep this short, so pay attention. So where to begin… Oh of course, the basic principle of screen printing itself. The principle of screen printing is very simple. This principle is pushing ink through screens on to a surface. “Wait really,” you are probably saying, “that’s it?" Yes that is it. In this section we’ll be discussing the basic concepts that you need to know to, well push ink through screens. These concepts are:
Design o Vector o Raster o Color separation
Characteristics of inks used.
Substrate/Printed Examples o Define substrate
o
What items are screen printed
Basic Concepts: Image Types: Vector vs. Raster
Both images look perfectly fine when kept small, but Vector images hold up better when made bigger because they are made of lines. Raster images become blurry when made bigger because they are made from pixels.
I still have half a page of room so… Here’s a cat
I should relate it to screen printing shouldn’t I… ok, it is a raster image
Basic Concepts: Ink types and Characteristics There are two main types of ink that we use for screen printing. Both of these ink types have different characteristics, and knowing the difference is very important.
The first type that I will discuss is plastisol ink. Plastisol ink is very simple to use and understand. The most unique feature about it is the fact that it is heat dried, which means that, well you have to get it really, really hot to make it dry. See, simple.
The second type of ink that I will educate you about is alcohol based ink. In order for alcohol based ink to dry, you must do absolutely nothing. This is because alcohol based ink is air dried, just like the paint you use to paint your house and make paintings.
Basic Concepts: Substrates Substrates are, quite simply, whatever you are printing onto. These include but are not limited to: -
Shirts Hats Signs Cars Window Clings
Design: Color Separation When making screens for a multi-color design it is very important to make sure that the colors are separated properly before you try and put them in the screen. Here’s an example See this Robot, it is made from two colors, in order to print it on a screen you must separate it into the colors that make it up, blue and grey.
And you do it like this Make sure to print in black
Print the rectangle black for the head And print the eyes and mouth white
Print everything else black for the features
Screen Printing Time! Well, actually, not yet. After you have your design separated into colors, must actually put it onto the screens. Here’s how to do that in four simple steps. 1. First you must take your design and print it onto film. Remember to separate it into different colors as necessary. After all colors have been printed, you have to run it through the conveyer drier.
2. After you print your design on film and run it through the conveyer drier, you must line up your paper onto the screen and tape it onto the backside of the screen ink side up. MAKE SURE THAT IT IS TAPED STRAIGHT. Use a ruler to accomplish this goal.
WAKE UP SHEEPLE!!!
3. After the design on film is lined up and put taped onto the screen you must expose the image using the amazing, wonderful, spectacular, exposing machine… wait what is it really called again, oh right the… exposing machine. Seriously, that’s it, talk about an anticlimactic name. So, anyway, you take the screen with the picture taped onto it and put it into the exposure unit and turn the machine on.
Make sure that the side you taped your paper to is on the bottom.
4. Now for the fun part, after your screen has been exposed you have to wash it out to make it show up and allow ink to come through to print your design. Use the pressure washer and start on the caved in or “squeegee side,” and then flip to the other side after your design begins to show up. Continue to wash it out until your design is completely washed out.
A person demonstrating proper clean out technique.
A washed out screen (Sorry that it’s blurry, it is a raster image after all)
Time to print (For real this time)
In order to print you must tape your finished screen and get it ready so that no ink gets through places you don’t want them to. First you put the thicker blue tape around the edges, then you cover up any unwanted holes and imperfections with lighter scotch tape.
After your screen is taped up to the point that you want it to be, you have to make sure that your image is lined up with your substrate. Once the image is straight you just have to use the squeegee and print the ink onto the substrate.
Congratulations you’re a screen printer now! Now for the not so fun part, cleaning up after yourself. This may sound like you don’t need any more assistance, but cleaning up is a bit different in screen printing. Here’s how to do it.
Clean Up Time 1. First you want to get any ink that you can off of the squeegee with a card so that you can put it back into the container it came from. Then you use a paper cloth to wipe off all of the remaining ink
2. Next you use a card to scrape excess ink off of the screens you used. Remember to put the ink back into the container it came from.
3. Next you use the chemical generally known as “apple juice� and spread it on the screen. After your screen is covered in apple juice, you use a paper cloth to wipe of the ink and apple juice
4. Dunk the newly cleaned screen in a chemical bath and wait about 3 minutes. After waiting, take it out and put it in the wash out booth, and wash out the screen. Make sure to get all of the orange emulsion off of the screen
5. Spray degreasing liquid on the screen and scrub it with a brush. After you get a good lather on it, wash it out again.
YOU’RE A SCREEN PRINTER NOW