What to pay attention to for perfect screen printing

Mesh count is one of the first variables that screen printers should understand.

Screens for screen printing aren’t just sold in different size. They’re sold in different mesh counts, which you can think of like the resolution of the screen.

Since screens are just woven nylon threads, mesh counts describe exactly how many threads you’ll find in a given area.

How to Decide Which Mesh Count You Should Use?

To decide which mesh count you need to use, you should consider the details of the print:

• What material (substrate) is being printed on?
• What ink is being used?
• How much detail does the image have?

One of the most important parts of successful screen printing is understanding how mesh count relate to print quality. Screens come in a wide range of mesh options. Ultimately, it’s your job to understand which mesh works with each garment, each image, and each ink.

While multiple mesh counts are standard in any screen printing shop, they all have their unique uses for the highest quality output.

Image detail

As the detail of your image goes up, so does your mesh count.

You don’t need a high mesh count for something simple like a one-color logo or large text. But for a complicated image, you’ll want the highest mesh possible.

Thickness and type of ink

If you use thicker inks (particularly inks that contain additives like glitter), you’ll want to use a lower mesh count.

This allows more space between the threads on the screen so that ink can pass through the screen freely. Because of this limitation with thick ink, you also need to consider that your images should be simpler.

When using extremely thin inks (like water-based inks or discharge inks), you’ll need to use a higher mesh count. The thinner threads and smaller gaps will allow less ink through.

Material (substrate)

Different materials (substrates) require different mesh counts.

Here’s why: both the screen you’re using to print with and the material you’re printing on are made out of woven materials arranged in a grid.

While your screen may be able to hold a great deal of detail, the t-shirt you’re printing on is made up of a bunch of tightly woven threads. So your t-shirt, too, has a “resolution” that it can hold.

Besides the makeup of the actual substrate, you’ve also got to consider whether the material is right for the ink you want to use.

The bottom line: make sure your ink, substrate, and image all align with your mesh count.

What Can Happen If You Choose The Wrong Mesh Count

If you’re just printing big one-color logos in black ink, you probably don’t need to think about mesh count too much.

But if you want to print anything beyond extremely simple logos and designs, understand what goes wrong when you don’t use the right mesh.

Blurred Imagery

The most common problem with choosing the wrong mesh is blurred images.

Typically, screen printers will try to print an image with too much detail for their screens. While the result may be passable, it often means losing a significant amount of detail in the finished image.

If you’re printing photorealistic images, halftones, or other images that require complex details, make sure you choose the right mesh count for the image.

Poor Ink Deposit

You can print with the wrong mesh count and achieve a decent image, but the actual ink deposit may be very poor.

If your mesh count is too high, you may not deposit enough ink. The image will appear faded, or the ink deposit will be far too thin to be durable.

If your mesh count is too low, you will probably deposit too much ink. The image will appear “blown out,” and the ink deposit will be too think. It’s likely you won’t be able to reliably cure this ink, and it may wash out.

Spoilage (Ruined Garments)

Using the wrong mesh is a surefire way to cause spoilage in your shop.

If you use the wrong mesh, you will almost certainly destroy some garments. Do you want to spend $5, $10, or even $20 on new shirts or hoodies for a customer?

Even if you are able to remove the ink from the garments, you’ve wasted valuable time in your shop and probably still need to burn your screens again.

Screens Dry Too Fast

This concern is slightly different than the others since it has to do with production and not print quality.

You often can’t correct for this: water-based inks used on high mesh screens tend to dry out quickly. The physics behind this are simple: since a high mesh count screen has so much surface area, more air is able to touch the mesh and remove moisture from it.

This means that you’ll constantly battle with hydrating and cleaning high mesh screens when producing a large order with water based inks. Certain supplements can help combat dried ink: retarders often keep flowing smoothly.

Shops using water-based or UV inks will tend to use a higher mesh count screen as well.

While you can’t switch mesh counts for this last problem, you can at least prepare for it by understanding that you’ll need to add humidity and some time to account for ink changes and screen cleaning during a high-volume run with high mesh counts.

Understanding Screen Printing Mesh Numbers

Know the different metrics and details that can inform your decision when you shop for screens. This will help you make better decisions.

Remember: screens are made up of woven threads. Mesh numbers help us describe the exact details of how thin or dense this weave is.

Let’s analyze what each element means.

The threads support the stencil.

The open areas allow ink passage. Familiarity with the meaning and importance of each mesh will make fabric selection easier—and consistent high-quality printing more predictable

• Mesh Count:

The number of threads per linear inch (norminal mesh count). Screen fabrics are woven in threads per centimeter and then the number is calculated to English measurement for sale into parts of the world that don’t use the metric system

Example: A fabric woven at 120 threads/cm equals 305 threads/inch. The figure is calculated by multiplying 120 x 2.54=304.8, this number is rounded up to 305

• Warp Threads:
  These are the threads that run along the entire length of bolt of fabric
• Weft Threads:
  These are the threads that run across the warp, from one selvedge to selvedge.
• Wire Size:
  This refers to the thickness of the wire used to weave the fabric. Wire size varies widely; the thickest yarns are used to weave coarse meshes, such as 24/250, which is 24 threads per inch and 250 microns in diameter. High mesh counts require finer yarns to achieve viable mesh openings as the threads per inch increase. A 305/40 mesh count is 305 threads per inch and 40 microns in diameter.

• Mesh Opening:
  The mesh opening is the open area surrounded on all sides by the weaving wires. Its size is measured in microns and is expressed as the width of one opening. While all mesh technical diagrams depict the opening as a perfect square, this is not possible when weaving with round wire. The weaving and finishing processes produce mesh openings that are less regular than perfect squares. Mesh openings tend to be more consistent in all plain weaves than in twill weaves. Mesh size is an important parameter in determining the printability of certain inks, especially those containing coarse pigments and metallic particles.
• Open Area:
  This is expressed as a percentage and simply refers to the ratio of the area “covered” by the holes to the mass of wire in a given area, usually calculated per square meter. Two fabrics with different wire diameters can have the same mesh count but different percentages of open area. This is important when selecting a fabric for a job with specific ink laydown requirements.
• Fabric Thickness:
  This is a measurement of the cross-section of the woven fabric and is used to calculate the theoretical ink volume of the screen fabric – or the cubic measurement of the mesh openings. While it may seem logical to assume that fabric thickness is the sum of the two wire diameters, this is not the case. The weave and finish affect the total fabric thickness measurement, which is always less than the sum of the two wire diameters.
• Tensile Strength and Yield Point:
  The tensile strength of a screen fabric is its ability to stretch without breaking. Tensile strength is usually measured by the amount of tension required to break. Low elongation fabrics have higher tensile strength than conventional fabrics. The yield point is the point at which the polyester deforms under tension, occurring before the breaking point. This “plastic deformation” causes the fabric to lose its ability to hold tension. The fabric will no longer hold tension, regardless of the tension applied to it. The purpose of tensioning the mesh is to achieve an optimum level below the yield point.
• Mesh Color:
  The fabric color is an important criterion as it affects image reproduction and exposure time. Yellow is a natural UV absorber and provides the best stencil resolution. Exposure times are longer than white mesh, however, the above diagram points out the dangers of using white mesh when fine detail is required. White mesh reflects light, causing undercuts, jaggies and loss of detail, and yellow exposure times are approximately 10% less than conventionally dyed mesh fabrics.

Only by knowing enough about printing screen can you print perfect pictures