Screen printing, as the name implies, revolves around using screens. A screen comes in two general types, stretch & glue and re-tensionable. A stretch and glue screen features either an aluminum or wood frame that then has mesh pulled over it very tightly and glued together. Stretch and glue frames are by far the most popular type of frame because of their lower price, but the tension cannot be adjusted. A retensionable frame uses the same mesh as a stretch and glue, but it is held by frame using locking strips, screws, or some other method that allows the mesh’s tension to be adjusted if need be. Newman Roller Frames are the most common type of retensionable screen print frames and while they are around 3 times more expensive than a stretch and glue they allow for greater control over a screen’s mesh tension, which is very important for registration. We recommend using stretch and glue frames for meshes under 200 and Newman Roller Frames for any mesh count higher than 200 as these typically are used to print higher detailed designs that require more exact registration.
While screen tension is very important for registration using the right screen mesh count is for a job is just as important. Screen mesh comes in a wide range of counts that start around 60 and go up past 360. The mesh count refers to the amount of threads within a given square inch. So, the higher the mesh count the more threads there are, which allows to hold more detail. A good way to look at mesh count is like DPI (dots per inch). The higher the DPI (resolution) the more detail can be seen within a design. Mesh also comes in two colors, white and yellow. White mesh is typically used with counts of 160 or less, and yellow mesh is used with counts 160 or higher. Yellow mesh is used because it does not allow light to bounce off of it like white mesh can, which is more of a problem on more detailed designs and is why it's used on higher mesh counts.
There are three main variables that determine which mesh count(s) should be used to print an order.
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What color of ink is being printed
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What color of product is being printed
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How much detail is in the color to be printed
Because each color within a design must be printed using its own screen, multiple screens with often different mesh counts must be used to print a multi-color design. For example: a 3 color print might use an 86 mesh to print white, 110 to print red, and 160 to print black.
The color of the ink and the color of the product variables will determine how hard it will be for the color to look opaque. Just like painting a wall, printing white ink on a black shirt is much harder than printing black ink onto a white colored product. If opacity is a concern, then a lower mesh count should be used as the less amount of mesh threads allows for more ink to flow through the stencil mesh and onto the product. White ink is by far the most common ink color that is printed and is typically done so on either an 86-160 mesh count screen depending on how much detail is in the design. The color of the garment often helps know how hard it will be for an ink to appear opaque. For example, it is a lot easier to make white ink pop on a royal color shirt than jet black because the product color is not as dark. Artwork with a lot of fine detail typically uses a minimum mesh count of 160 or higher. Remember that the higher the mesh the more opacity is sacrificed. Screens with mesh counts of 230 or higher can be used to print CMYK Process (full-color) designs using just 4 colors, but the registration must be exact so screens with high tension must be used.
Each mesh count has a different exposure time. For instance, the lower the mesh the longer amount of time it takes to burn a design. However, if a screen uses yellow mesh, then it takes much longer to expose than white to make sure all of the detail is burned. Every exposure unit and emulsion used to coat a screen is different among other variables, so it is important that your shop take the time to dial in the right exposure times for each mesh count, emulsion used, and the amount of coats of emulsion.
