The Beginners Guide to Sounding Like A Screen Print Pro

Silkscreen printing is a great way to have fun, make some money and expand yourself as the creative being you know you are! But it’s hard to get started sometimes when you have no idea what you’re talking about. So this is my beginners guide to the meanings and uses for all the terms silkscreen printing pros use to, well, sound like pros. Learn these and you can walk into any supply store, art store or printing shop and get the respect you deserve- and the products you’ll need.

Silkscreen Printing: Other wise known as screen printing, silkscreening, silk screening and serigraph. These are ALL the same things. The most common way to refer to the process is ‘screen print‘ mostly because there is significant confusion in the general public about the ’silk’ in the term silkscreen printing. Frankly, silk isn’t really any part of the process- not since the 60’s at least. It was used as the mesh for the screen print frame but has been replaced by polyester mesh which is vastly superior. Officially, screen printing is a printing technique that uses a woven mesh to support some sort of stencil (we’ll look at stencil definitions in another post). That stencil can be made of a lot of different things but each stencil system will act as a resist for ink, blocking out some areas and leaving others open to the mesh. The printer passes a squeegee over the screen which forces the ink into the open areas of the stencil and through the mesh onto your substrate.

Substrate: This is the term that screen printers use when they talk about the surface that they will be printing onto. So ’substrate’ can represent just about anything you can manage to print onto; paper, fabric, plastic or glass just to name a few. (I’m sure if you thought about it long enough you could come up with a few novel substrate surfaces to print onto.) The substrate doesn’t even have to be flat; silkscreen printing machines often print onto round surfaces like bottles. You’ll notice that when screen printers are referring to their screen print frames they might refer to the squeegee side and the substrate side. So it would follow that when referring to the frame the substrate side would be the side that touches the surface to be printed. The squeegee side is the side on which the squeegee is used. 

Squeegee: A screen print squeegee is longish rectangular tool often made from wood with a rubber blade inserted into it. As you pass the squeegee over the silkscreen frame mesh it squeezes the ink through the open areas of the mesh depositing it onto your substrate surface.

The squeegee comes in quite a few shapes and sizes. The handle part of the component is of least importance. What you really need to know are the technical specs on the blade- the rubber part. The squeegee blade can be square, rounded or pointy and it can be hard or soft. Generally, flexible squeegees with rounded blade edges are used for fabric printing, while hard, square edged squeegees are for printing on paper, wood and other surfaces. The lower the durometer the softer the blade. I have always used a 60 durometer square blade. (I print mainly on fabric and I like the sharper image that a square blade gives me and the softness of the 60 durometer blade). 60 durometer is great for high density printing because it allows a good amount of ink to roll through the stencil. It can be a tough blade for thicker inks but I have always managed nevertheless. There are many companies that sell a 70 durometer blade as their standard and that is OK too. And there are some blades that have multiple durometers within a single blade. The triple durometer squeegee is great for more difficult types of printing applications. Many screen printers use it for process printing or printing of thicker inks (such as white or opaque inks). 75/90/75 durometer blade means that your blade has softer edges for smooth printing application but a stiff center for a rigid blade angle. 80 Durometer squeegee is great for more difficult types of printing applications and thicker inks.

Screen Mesh: The mesh is the fabric part of your silk screen frame. It is made from high grade monofilament polyester. The mesh can be yellow or white and range in thread count from 40 to 400. 

Fabric printers might use 80 or 110 thread/in. for applications where they need to lay down white or light colored inks on dark fabrics. As the mesh count rises, the amount of ink flow and deposit thickness decreases. In graphics applications on non-porous materials like paper, less ink is required for coverage, and higher mesh counts above 300 threads/in. allow finer images and details to be printed. I use a white 110 mesh and sometimes a white 156 mesh most often because I print onto fabric and with water based pigment inks. There are some inks that have specific characteristics that put limitations on mesh counts. UV inks require thin ink deposits for proper curing and won’t dry in the screen, so mesh counts above 305 are used. When you get different fabrics in the higher mesh counts, you will notice there are white meshes and yellow meshes, many in the same counts. Generally, whites are less expensive than the dyed/colored mesh.  When exposing a positive on white mesh, especially halftones and fine lines, you may notice the edge definition and the quality of the image is rougher than the positive. This is due to light bounce. The white threads reflect light in different directions and produce soft edges on the stencil. Yellow mesh minimizes this effect and produces sharper images. This is not so critical on coarser meshes where details are bolder (i.e., for t-shirts or basic designs with flat colors) But it does become critical in halftone or fine-detail printing. You can buy the Screen Mesh here online.

Note that stencils on white meshes expose faster than those on yellow mesh fabric. You should adjust your exposures to take this into account.

Screen Print Frame: It’s pretty critical that you know what this is and how to use it. (Really?!?) Screen print frames come in either wood or aluminum, pre-tensioned or tension-able. Screens with aluminum frames last much longer than wooden frames which warp after repeated washings. Aluminum screens usually cost more than wooden screens of the same size but last so much longer the extra money is definitely worthwhile. A sturdy aluminum screen will continue to lie flat on the printing surface after multiple uses and the mesh is pulled much tighter around an aluminum frame which produces a crisper printed image. They’re also a lot easier to wash out than wooden screens.

The other type of screen frame is the retensionable frame sometimes referred to as roller frames. Retensionable frames consist of rolling bars on each side to which mesh is attached. The bars are rotated to bring the fabric up to tension, then locked down to maintain the tension level. Screens that lose tension can be re-stretched as needed.

But before you invest all kinds of money you should check out my post on how to build yourself a silkscreen printing frame from just a few household materials. It’s fast and easy, here’s how to build your own screen print frame.

Film Positive: The film positive is developed from the artwork you wish to print and is what you use to ‘burn’ your image onto your screen when you are using the direct stencil method with photo emulsion. The artwork istransfered onto acetate film in black and white. Grey areas will not expose properly. If you wish to print gradients then your artwork needs to be converted to a halftone screen. The black of the image will absorb the light from your light source thereby keeping it from hardening your emulsion. The white ares let the light through and harden the emulsion. Once your are finished exposing your screen you’ll wash it out and the areas that did not harden will was away and these become your open stencil areas.

There are lots of ways to make a film positive. One way is to directly illustrate your image onto clear transparency film or thin vellum with a black opaque marker or india ink or illustrate it onto plain white paper and have a copy shop photocopy it for you onto transparency paper. Or you could cut your image out from rubylith and adhere it to a transparency. Another is to illustrate an image on your computer and print it out onto transparency film that is meant for either ink jet or laser printers. (I find that you often need to use two of the same printer produced transparencies taped together to achieve an opaque black). You can also bring your artwork to a pro shop that will create an actual film positive for you but that cost can be as much as $12.00/sq. foot. The CHEAPEST way but not always the best way is to produce your artwork onto plain white paper with black ink and then use baby oil to coat the paper to turn the white of the paper translucent. When I am testing a print or doing a one-off I often use this method. It is much more difficult to wash out your screen easily with an oiled paper positive than a truly opaque black and transparent positive. To be sure, test for yourself and see what your results are like with different methods.

This information should get you started in understanding the basics of silkscreening. Don’t hesitate to look through other posts for more information, DIY projects and tutorials. And of course, email me with your questions and I will try to answer them in a Q&A post in the near future.