Chapter 4
Choosing The Frame And Mesh Count
Once you have created your art and output it to a film positive, you will be ready to prepare your screen to receive the image.
You can make a decent commercial grade screen yourself with the appropriate equipment and/or tools as well as professional grade supplies or you can buy a screen pre-made with mesh already stretched on it ready to go. Wood frames can be good if they are made well and sealed with lacquers. But wood frames age quickly and lose their rigidity especially when they are used and reclaimed on a regular basis. Metal screens work best if you plan on reusing the same screen for many different jobs as they need to be printed. An aluminum pre-stretched screen is usually the best value for a high return on investment.
VIDEO: Should You Stretch Your Own Screens When First Starting To Print?
Standard textile screens are made with rectangular metal tubing having outer dimensions of 20 X 24. They come in many sizes and materials but I have found the 20 X 24 aluminum frames to be the best for tee shirt printing on a rotary textile press. It is the standard in the industry. You can purchase screens pre-stretched with mesh. They are economical in the consistency of the quality of the frame and tension. It is very important to have a rigid squared frame with tight mesh firmly secured to it. The performance of your screen and stencil will depend on the quality of the frame and screen itself. Tighter mesh prints a better print with less ink and higher detail. The better the screen performs, the easier it is to print a higher quality print. The easier you can print a high-quality print, the more money you can make per hour.
VIDEO: Screen Mesh Tips
There are several different factors that should be looked at before deciding which type of frame material to use for your screens. Many people simply go straight for the cheapest solution which is almost always wood in the short term. But there are pros and cons for each material and it is important to understand them. Learning about cons during the actual usage of the screen can be frustrating, annoying, time consuming and even costly.
It is also important to remember that with each different type of frame, there may be different ways of stretching the mesh onto it. The need for different tools may also be required for certain stretching methods.
The most common material used for frames when starting out is wood. There are a few key benefits to using wood when you are on a low budget or working at home. With some basic carpentry skills and tools, you can fashion your own custom size screens with wood. Using wood is inexpensive and allows for a lot of flexibility when screen printing at home. Wood frames are also somewhat easier to stretch by hand.
VIDEO: Wood Vs. Metal Frames & The Tension Meter
VIDEO: Metal Screens & Mesh Tension
However, wood frames have the most problems associated with them. Aluminum pre-stretched screens are the best option. The cost of one should be made back within the first commercial print job. Aluminum screens can last a very long time and print thousands of prints easily. Wood frames will weaken and become loose at the corners after being exposed to water during washout and/or reclaiming. They can cause problems with registration due to multiple reasons. First wood frames loose tension much faster than metal. The wood frame is generally not sturdy enough to retain their structural integrity as time progresses. Wood frames often give and flex at the corners and may even bow due to initial tension from mesh stretching. Obviously, wood is also absorbent. Therefore, wood frames will not only absorb water which causes them to deform, misshape and warp, but they will absorb chemicals as well. Even the relative humidity of your geographical region may affect the shape and integrity of a wood frame. The wood may even swell and cause splintering which is not a great idea for your printer. Lacquered wood frames only delay the inevitable.
Many metal frames are hollow and light weight. There are metal frames for certain applications which are very heavy. For manual textile printing you want to choose a light weight frame. Aluminum frames are even lighter than wood frames. Heavy screens may cause premature armature wear on your textile press and unnecessary fatigue for the printer during longer print runs. Aluminum and steel are the most common types of metal frames. Most often aluminum frames will be lighter.
Aluminum frames can be used to stretch all kinds of mesh. They are light weight, rigid, durable and corrosion resistant. They tend to be easier to clean but it is important to note that they may be less resistant to alkalis and acids. Smaller manual frames are low cost and available in a variety of mesh counts.
Steel frames will have the absolute most rigidity for screen printing with very high tension situations. The biggest problem with steel is the weight. They will rust if they are not painted with enamel and often need to be re-painted when being re-stretched. Strong adhesives or solvents may be damaging to their finish.
For most standard manual textile screen printing applications an aluminum frame will be the most practical solution. The drawback for home based printers is stretching but today these types of frames may be purchased easily with mesh already stretched on them. With a little care and knowledge, the mesh will last for long enough to pay for the entire screen and much more. A lot of beginner's troubles and problems may be eliminated or reduced simply by using an aluminum frame. They cost less to ship and you will have an easier time using them compared to wood.
VIDEO: What’s The Best Screen Frame Size For Printing Garments?
At this point it is wise to choose the appropriate mesh for the artwork. A common tee shirt mesh count is 110 but it is not the default mesh for textile printing. Mesh count numbers work in reverse. The bigger the number, the smaller the openings will be in the mesh. The smaller the number, the bigger the openings will be in the mesh. 355 mesh is standard for printing four color process. Obviously the bigger the mesh opening, the more ink will easily pass through the mesh onto the shirt.
Standard spot color line art works well on 110 mesh. If there are fine lines and some detail in line work a 160 mesh may suffice. 200 and 230 mesh counts can do high detail as well as some halftones around 45 LPI. Process halftones with 55 LPI or higher will work best on a 305 or 355 mesh. A lesser line count like 36 to 40 LPI for a 1 color halftone should work on a 200 mesh. These are by no means any real guide to setting up halftone screens. There are formulas and ways to determine the halftone line angle. Your halftone will be specifically made for your mesh count. Halftones can be tricky to print and need to be set up to avoid Moiré patterns with the mesh itself. Make sure you do your research on this before attempting to do it yourself.
As beginning screen printers, many people start with one or two screens of the same mesh count. Some people buy used equipment with a few screens and may have more than 1 mesh count on hand. Yet other people printing at home may not even be using screen printing mesh. But it is important to understand what the mesh count means and how you can use mesh counts to make printing your designs easier.
We will try not to get technical here at all. But there are certain principles you must understand to choose your mesh appropriately for the job you are printing.
Mesh geometry is the description of all two and three dimensional aspects of the mesh construction. The two basic factors in mesh geometry are the mesh count and the thread diameter. The mesh count refers to the number of threads per inch contained in the mesh. The thread diameter refers to the diameter of the thread before it has been woven into the mesh.
It is important to remember that mesh geometry will define the characteristics of the mesh. The mesh opening, mesh thickness and the theoretical ink volume obtainable by the mesh are all determined by mesh geometry.
Mesh geometry affects:
- Printability of fine detail, lines, and halftones
- Crisp resolution of edges in the design
- Ink release properties
- Printing speed in relation to your ink viscosity
- Ink volume thickness
- Ink consumption during printing
Please note that this article is geared more for manual screen printing as opposed to automatic screen printing. The same printing application will call for different mesh counts when the job is printed manual or automatic. More specifically mesh opening rather than the mesh count can be the determining factor in automatic screen printing.
Generally, a lower mesh count like 110 will be easier to print with and deposit more ink. But when you want to print fine lines and detail, the 110 mesh becomes difficult to work with. 110 mesh is not the default mesh for textile screen printing. You need to choose the mesh appropriately for your printing application. The emulsion is not able to stay adhered to 110 mesh in finely detailed areas and often produces jagged edges in the final print. And 110 mesh is most always white. White mesh causes the light to bounce off and scatter in the exposure unit when burning your artwork. This can affect your ability to render detail as well. This will always occur with white mesh of any thread count. Having a point source exposure unit is better for fine detail and halftones as well.
An easy way to obtain the detail you want is to move to a higher mesh count like 135, 195 or 200. Once you get to 200 mesh counts and above, they are most often dyed yellow or amber/orange. The mesh is dyed to eliminate or reduce the light scattering effect of white mesh. To render fine detail or halftones a dyed mesh is preferred so that stray light is absorbed into the dye, rather than bouncing around.
VIDEO: Yellow Screen Mesh Vs. White Screen Mesh
Working with higher mesh counts that are dyed is a little different in a few aspects. It is less forgiving all around.
Some important notes to remember with higher mesh counts and dyed mesh:
- The dyed mesh may or may not increase your exposure time. Higher mesh counts naturally hold less emulsion and can therefore sometimes have the same exposure time or less if you are under exposing for details.
- Pinholes and premature stencil wear or breakdown can be a problem if the screen is not well prepped for coating with emulsion.
- The thinner stencil, necessary for fine detail, wears quicker over longer print runs.
- Higher mesh counts hold less emulsion creating thinner stencils. Strong adhesives like tape can pull the emulsion off the mesh thus ruining your stencil. Proper mesh prep can eliminate this problem.
- Halftones need to be created specifically for the mesh count being used to avoid moiré patterns.
- Higher mesh counts generally cost more.
- Higher mesh counts are harder to stretch without tearing or popping.
If you choose your mesh appropriately for the artwork you are printing, then you will have an easier time achieving your end goal. Here is a general guide to choosing mesh counts.
Use a 28 to 30 mesh count for printing many brands glitter inks. Always check with the manufacturer of the ink about this. This mesh will print a very high volume of ink and have a thick coat of emulsion making it difficult to expose.
Use an 85 mesh count for athletic printing, opaque ink deposits, thick puff ink, and some shimmer inks. This mesh will print a very high volume of ink and have a thick coat of emulsion making it difficult to expose.
Use a 110 mesh count for heavy coverage on dark shirts, solid under base prints, puff, metallic, some shimmer inks, and for certain transfer printing. This is a great mesh count for high opacity inks on any dark garments. This is where we usually start when printing garments.
Use a 155 or 160 mesh count for general printing on white tee shirts & under basing on dark shirts, prints on nylon jackets, and thinner inks. Many thinner plastisol inks will print well with this mesh count.
Use a 200 mesh count for printing on light colored T-shirts with fine detail, line work or halftones of around 35 to 40 LPI.
Use a 230 mesh count for printing on light colored tee shirts with fine detail, line work or halftones of around 45 LPI.
Use a 305 to 355 mesh count for process color on light shirts, or for overprinting a halftone on a white under base on dark shirts. You should be able to pull of halftones of up to 65 LPI but a 55 LPI is most common.
VIDEO: Choosing Your Mesh Count
Most lower mesh counts will most always be colored white. Dyed or yellow mesh usually starts at about 200 mesh and higher. If you have been using a 156 or 160 mesh count or lower that is yellow or amber in color, that is a specially dyed mesh and is not normal to find.
An older way of thinking about screen printing tee shirts or other garments is to use lower mesh counts to achieve better coverage and color. While it is true that leaving more ink on a fabric will tend to make it opaquer, there are better, more efficient ways of getting the same or better results. You will have to abandon your desire to do simple spot color jobs on mesh counts like 110 or lower and adopt the use of newer mesh counts.
To use the newest monofilament polyester screen fabrics to your advantage, you will need to understand a simple characteristic of screen printing mesh. We will be focusing on how a fabric's thread diameter affects the mesh geometry. We will look at how the thread diameter of the mesh will affect the overall ink flow or increase the mesh opening for any given mesh count. We will try not to get over technical here but there is a certain amount of tech talk needed in order to continue.
Keeping that in mind, let us look at two mesh counts for the purposes of illustrating the concept. If we have a mesh count of 110 which is made with a standard 80 micrometer thread, we know the mesh opening is about 43% with a mesh tension of 44 N/cm, (Newtons per centimeter). Just remember that we usually are using screens at about 20 to 25 Newtons on 110 mesh. This is for the purposes of explanation. Now, 43% is the number to focus on here because this represents the percentage of open area of the mesh at a specific tension. The higher this number is, the better the ink flow will be through the mesh. Now we also know that printing with 110 mesh has its own inherent qualities like loss of detail or "saw tooth-ing". And it also provides for a rougher ink surface when printing an under base. Now what if we could use a higher mesh count that had a similar or better mesh opening ratio?
Let us now consider a mesh count of 150, made with a 48 micron diameter thread and stretched at 28 N/cm. This screen will have a mesh opening ratio of around 51%. If we look at the two percentages, you will see the 110 has a 43% mesh opening and the 150 has a 51% mesh opening. So, even though the 150 mesh is a higher thread count in comparison to the 110, it still has more open area. This allows for greater ink saturation in the print area, improving the opacity and the color intensity of the print. Although this mesh may have a little bit lower theoretical ink volume, it will have better ink flow characteristics and allow a reduction in squeegee pressure too. This will produce a thinner, more even, and smooth ink deposit which creates a softer hand or feel to the print. Mesh like this is sometimes referred to as "thin mesh".
VIDEO: Mesh Tension Review & Summary
This type of mesh can have great advantages for many reasons. Reducing squeegee pressure can increase image detail. It can also reduce stencil drag which in turn improves registration. Also, it is important to note that ink opacity or coverage is affected by factors other than ink volume such as the substrate and even the ink quality itself. In standard conditions, a smooth, even deposit of a lesser amount of ink will produce a more colorful and opaque print than applying thicker layers of ink.
Using a mesh like the 150/48 or maybe a 135/40 or even a 125.70 for a white under base is an excellent usage of this type of mesh. The under base will be able to render details needed for the design and it will produce a better surface than would be produced by the 110/80 mesh. As you may already know, a smoother, thinner, more consistent under base is ideal for halftones. A thin mesh could also help reduce clogging with water-based inks and back flooding.
Some advantages of "thin mesh":
- Better ink flow with less effort
- Great coverage with minimal ink volume
- Creates a smoother, more consistent surface
- Requires less squeegee pressure
- Improves print quality or detail
- Easier to achieve stencil detail
- Elimination of fabric interference in halftones
- Creates a softer hand print
VIDEO: What Is The “Best” Mesh Count?