What is Screen Printing? 

Screen Printing is forcing ink onto a surface through a prepared mesh screen to create a picture or graphic. Screens come in different mesh counts allowing us to achieve different desired details.

Screen Printing is a unique art that had its first appearance during the era of Song Dynasty Art (960-1279) and Later in Europe during the 18th Century. During the 19th Century silk became more available and was incorporated into the mass production of prints.

Although Screen Printing is an Art itself, In the Business world Screen Printing is MANUFACTURING NOT DECORATING, these processes have to be controlled with no guessing.

Screen Printing is a Tribal Learning Process in which every printer learns their own way of printing. But, every print shop is different and has their own unique processes for efficiency and the highest quality product. (Control and Consistency)

There are hundreds of factors in Screen Printing to take into effect. This guide will help introduce the main processes of Screen Printing at Brist and the Main Factors that create a high quality print.

Once designs are finalized, the production artist separates each color of the design into a separate layer in photoshop or Illustrator.  Once each color within a graphic is separated it is printed onto a transparency in black ink. These transparencies are then used to burn the image into the screen. During the screen printing process these colors will be registered to one another (using our press) to make the final design. (each color within the design needs its own transparency and screen). To learn how transparencies are used to burn a design into a screen please refer to the “Emulsion and Exposure” section.  Printing artwork on Transparencies or Film is the traditional way to expose artwork onto a screen. 

Video on Transparencies:

Watch the video below to learn more about Film and Transparencies:

Every ink color applied to a garment  requires its own screen. These colors are then applied at separate times to the garment on our screen printing press to make the finalized design. 

In order to achieve a desired detail, ink thickness, and opacity, we use screens with different mesh counts. A screen with a lower mesh count means the screen’s thread count is lower, creating larger pores in the screen for ink to pass through . A screen with a higher mesh count has a higher thread count, creating smaller pores in the screen for the ink to pass through.

Mesh Count:

Low Mesh Count: 

A lower mesh screen is often used to print thicker types of ink. Using a low mesh count screen is also known for larger deposits of ink, creating a more opaque image (especially with lighter colored ink on dark garments) Low mesh counts are also used when applying special metallic inks and gold foil glue. 

High Mesh Count: 

A higher mesh screen is often used to print a thinner deposit of ink with a higher detailed image.

The most important area of any print shop is the Dark Room and the care of your screens. Screens are the main tool in the printing process, if your screens aren’t taken care of, or cleaned properly you will not have a quality print. Many print shops expect quantity over quality, but at Brist we want to keep the highest quantity with the best quality product.

Emulsion:

Emulsion is a light sensitive chemical that is used in the process of burning an image into a screen. Emulsion must be kep in a dark room away from UV light. When UV light is exposed to 

Emulsion for an extended period of time, it will harden and solidify to the screen’s mesh. All of our screens are coated with emulsion before they are exposed. In order to remove the emulsion from a screen that has been exposed to UV light,  a special chemical must be used. 

Exposure:

In order to expose a screen, we use a high powered exposure unit. This exposure unit is a light table that exposes a high volume of UV light to the screen. In order to burn an image into the screen we must use a transparency. The transparency is laid onto the glass light table (exposure unit) first. After this, the screen (which is coated in emulsion) is laid on top of the transparency. When light is exposed to the transparency/screen (from below the glass) via the exposure unit the dark black ink on the transparency blocks out the light from exposing the emulsion. All the emulsion that is exposed to the light hardens/solidifies, and the emulsion that is not exposed to light (where the transparency is present) remains soft. Once the screen has exposed, it is washed out with a pressure washer. The soft emulsion ( where the transparency image was) falls out of the screen (opening the area for ink to flow through the screen). The hardened emulsion that was exposed to light remains on the screen. 

Video On Emulsion and Exposure:

Watch the video below (starting at 1:30) to learn more about Emulsion and Exposure:

Poor tension is the cause of:

• Mis- Registration

• Halo-Imaging

• Mesh marks

• Frosting peaks

- Poor tension causes a delayed snap within the screen which will cause ink build up, especially within the under base of the print.

- Proper consistent tension = Faster print speeds, faster registration, better ink yield, better opacity with finer mesh counts.

Reclaiming Screens: 

Before Screens are reclaimed make sure they are removed from the Brist Screen Library System on the Brist Wiki.

• Again, screens are the most import tool in screen printing. Treat your screens with the highest care you put into your print. A shitty screen makes for a shitty print.

• Reclaiming is another very important factor in screen printing, the screens must be fully cleaned and degreased from all oils and chemicals before the emulsion coating process.

• Currently at Brist we are using a dip tank in which the screens soak in a emulsion removing solution for a period of time. There may be changes in the future where we switch to the SAATI emulsion remover, where the emulsion is removed in the spray out booth. The dip tank solution is hard to regulate and is not cost effective.

  • SAATI Chemicals: These are too be used in the wash out unit only

  • IR26 Ink Remover

  • PW4 Press Wash/ Screen Cleaner

  • ER6 Emulsion Remover and Degreaser

• Before removing the emulsion make sure all the ink and tape is removed from the screen using the mineral solvent. Many of the inks that are used within the shop cannot be poured down the drain and can contaminate the water.

• After the ink and emulsion are both removed from the screen spray Degreaser on both sides of the screen as well as rinse out both sides of the screen. Always apply to a wet surface.

• If a ghost image appears from the previous print use the Ryonet Sgreen stuff and a sponge to remove the ghost image.

• Do not use haze removers during the reclaiming process, they contain high Alkaline and damage the mesh of the screens.

Taping Screens:

Every print shop uses different types of tape for their screens. The most common type of tape shops use is standard 2in brown packaging tape. Although this tape is cheap and easy to use, during the reclaiming process it will leave adhesive residue that will break down the mesh of the screen.

At Brist we use a 3inch wide adhesive tape that is made specifically for screen printing. This tape is purchased from Ryonet and does not leave an adhesive residue. For water based and discharge prints be sure to tape off the entire screen with the 3in durable blue tape.

When taping be sure to split the center line of the tape into each edge of the inside of the screen, as well as every corner. On the bottom side of the screen put a strip of tape on each edge of the screen where the edge of the squeegee touches the screen. This prevents the edge of the squeegee from breaking down the emulsion and pushing ink through onto the garment.

Within the varied printing processes there are many varieties of inks which are made to be printed on garments. Many garments are made of different threads or fabric such as 100% cotton, tri- blends, and full polyester garments. For different garments, there are different inks which are specially made to adhere to the garment after the curing process. At Brist we mostly print with Plastisol inks because they have the longest shelf life and have a quick dwell time during the curing process.

We use three different types of ink here at Brist. These ink types include plastisol, water based, and discharge. Each type of ink has different properties and requires different printing and curing techniques. 

Plastisol Ink: 

Plastisol is the most commonly used ink in the screen printing industry. It is an oil based ink that lays on top of the garment. Plastisol is easiest and most forgiving type of ink to use when screen printing. Brist uses plastisol for about 95% of our jobs. Plastisol cures at 320 degrees Fahrenheit.  

• Plastisol inks are the most efficient and fastest curing ink in Screen Printing. These inks are the fastest curing and have the longest life on a garment compared to other inks. Most plastisol inks cure at 320 degrees, but a Brist we cure our plastisol inks at a dryer temp of 360 degrees and a belt speed of 13. You can use a temperature gun located at the end of the dryer to ensure the ink is curing fully.

Water-based Ink:

Water-based ink is much thinner than plastisol and is generally printed through higher mesh screens. Unlike plastisol which lays on top of the garment, most water based inks lay into the garments fibers, offering a very soft hand feel. Printing water based ink is a more difficult process than printing plastisol and requires more techniques and planning on the front end. Water-based inks are often much less opaque than plastisol inks, so they often require multiple layers or a white base. Water based ink requires forced air to cure. The forced air evaporates all moisture from the ink allowing it to cure to the shirt. Because of this, water based ink must be in the conveyor dryer for a much longer duration of time than plastisol. Because of the additional factors that go into printing water based ink, we must charge a higher price. 

• Dwell time during curing is much longer. Flashes must be turned up to at least 245-260 with a 10.5 second dwell time and a 15 second index time on the press. For water-based inks the water must fully evaporate from the ink to cure properly. The dryer must at a temp of 330 with a dwell speed between 3 and 5. ( at least 90 to 120 seconds at 320 degrees). 

Discharge Ink: 

Discharge is a type of ink that lays into the fibers of the garment (similar to water base). Discharge ink is a type of ink that must be activated by an activating powder. Once activated, discharge ink is printed onto the garment. Discharge ink is often very hard to see once printed. After printing, the garment will go through the conveyor dryer. When Discharge is exposed to heat, a chemical reaction takes place and the discharge ink removes the color of the shirt with the color of discharge ink. What is very unique about discharge is that you can print one layer on a dark garment . Although discharge has many positive properties (soft hand, no base needed, etc.) it will only work on particular garments and colors.  Because discharge is bleaching and re-dying the fabric of the shirt pantone colors will not always match exactly to a pantone book. The colors will also be more matte and faded compared to standard plastisol. 100% cotton garments are suggested. Discharge will not activate on any synthetic material.    

• Discharge is a chemical additive that is usually mixed right before printing. The discharge agent dyes itself into the garment, so it is important to pay attention to the material of the garment. When registering discharge on the press always register with a minimal amount of plastisol ink, clean screens and then apply the discharge ink to the screens. For discharge inks the red chili flash units should be turned up to at least 300 degrees or higher for the discharge to activate. Once off the press the dryer should be turned to 330 degrees with a belt speed of three. Adjust the temperature of the dryer if discharge does not cure or fully activate.

  • The Discharge additive that we use at Brist can be mixed with any standard water based ink or water based PMS color.

  • Mixing the discharge additive always mix 8% of the discharge power with the ink. Add more if needed

  • Discharge can only be printed on 100% cotton garments, and natural threads. This additive does not work on pigment dyed garments or re-dyed garments. Many colored garments do not work either, such as Royal Blue, Forest Green, Red and Maroon, are not dischargeable.

*Note, curing discharge and water-base inks must have enough heat and forced air to evaporate all water from ink.

• Poly Based: These inks are made specially for 100% Polyester shirts, as well as Tri-Blend t-shirts with over a 50% Polyester blend. Poly Based inks are also used to print on various nylon garments, but nylon garments can only have one or two colors printed on them with no under base. Although screen printing on nylon is fast, Ink does not last as long as vinyl transfers do on the garment.

  • Poly Based inks must be cured at a dryer temp of 345 degrees, with a belt speed of 14. (or 45 seconds at 320 degrees). 

  • Poly Block: Polyester garments tend to dye migrate more than standard cotton or tri-blend fabrics. The poly block is a grey poly base that blocks the migration and still hold a bright, vivid color to the final print. Most poly block inks contain a charcoal pigment that prevents pigment dyes in the fabric from bleeding into the plastisol ink. 

Ink Opacity: 

Opacity is a word that is used often in the screen printing industry when referring to the way ink appears on garments. All ink colors and ink types have different levels of opacity. Plastisol is a thicker ink, so it generally has a higher level of opacity, where water based ink is a thinner ink, so it generally has a lower level of opacity. 

Layers of Ink / White Under Base: 

The number of layers of ink printed onto a garment

makes a significant difference in how the ink appears. The industry term for printing and layering ink is a print flash print. This means the ink is being printed, flashed (dried in between colors while still on the press) and then printed again with another layer of ink on top of the previous layer. 

A scenario where multiple layers of ink would be required is if we were printing a light color of ink on a darker garment. If we just print the light colored ink directly onto the darker garment, it would appear dull and grainy (an almost vintage look). In this case, we would usually print a base layer of white in order to give the next color a bright surface to lay on top of (allowing the second ink color to appear the way it looks before it is printed. In some cases certain ink types and or ink colors have very low opacity (Example: pantone matched colors) and may require two white base layers before the final ink color is printed on top. 

For more examples like this one, click the link below!

Pantone Matching: 

Many customers require specific pantone ink  colors for their garments. This is often due to their company's specific brand guidelines. When a customer requests a specific pantone color, it is very important that it is spot on. Please click the link below and scroll to the bottom for a pantone printing guide:

Plastisol Pantone Matching: 

Most custom plastisol pantone color that is mixed falls on the lower opacity spectrum.  Because of this, it is important to understand that even on lighter colored garments (except white) we always recommend a base layer of white to truly achieve the desired pantone color. This will assure that the ink that is printed onto the garment remains consistent with the way it looks when it is mixed.  Some clients ask for a more vintage or thinner looking print with pantone colors. If the pantone is printed without a base layer the pantone will create a color tone that is similar to the fabric color it is printed on. (Reference Layers of Ink). 

Water Based Pantone Matching: 

All water based pantone colors that are mixed fall on the lower opacity spectrum.  Because of this, it is important to understand that even on lighter colored garments (except white) we always require a base layer

of white to truly achieve the desired pantone color. On dark colors it is important to lay down two hits of white then the pantone color. This will assure that the ink that is printed onto the garment remains consistent with the way it looks when it is mixed. 

Discharge Pantone Matching:

Discharge pantone matching is very different from plastisol and water based inks. Because discharge ink replaces the color of the garment with the color of discharge ink, it is often very possible that the pantone color will not appear the exact same after the item is printed. Discharge ink does not require any under base to achieve bright and vibrant colors (After print).  We can always offer to match the client's custom pantone color, although it is very important to inform the client that there is no guarantee that the pantone color will remain the same after print. This also applies to all stock discharge ink colors as well. If the pantone color is very important to the customer it is best to sell them on plastisol inks.

Mixing Plastisol:

•  At Brist we are currently using the Rutland Mixing System. We charge every client a 15$ fee for every PMS color mixed for each new job.

• The Rutland mixing system can be looked up on any computer within the production area. Any new PMS color is mixed in a 32oz cup located next to the inks. Always mix 600 grams to start for every PMS color. Pantones are only referenced with a coated pantone book. 

• Always use the Rutland mixing colors to mix a new color. If a PMS color requires black or white ink always mix the required colors first, and then slowly add white or black until the color matches the swatch in the Rutland color book.

• Always zero out the scale before adding a new color.

• If you are mixing a custom standard bucket color, follow the Equation on the wall, located above the ink mixing station. The equation will tell you how many grams to use for each color. Some of these colors include: Light Orange, Light Teal, Seahawk Green, Cream, and Grey tones.

Special Effects Ink for Plastisol:

Since plastisol ink is the most common ink used in the industry, many ink distributers are creating new additives for plastisol inks. Special effects additives are made to mimic the different effects discharge and water based inks provide. These additives are made to create 3D effects, textures, and metallic shimmers which are not available for standard prints.

• Special Effect inks can be used together or by themselves to create unique prints that still have a speedy turn around time.

• Sculpture, Rock and Puff additives Turn into a 3D texture after ink is fully cured. These additives must be the last color or screen printed. The additive reacts in the dryer and cannot be flashed on the press.

Metallic Special Effect Ink:

• Metallic Inks are made to duplicate foil transfers but are trickier and pretty limited to what you can print with them. These inks usually only print well as a single color, but if they are included in a multi-print, they must be printed last with a smaller amount of surface area. Metallic inks can be printed over a white base but will have more of a shine with a clear coat base or poly block base.

Direct-to-garment printing (DTG) is a process of printing on textiles using specialized aqueous ink jet technology. DTG printers typically have a platen designed to hold the garment in a fixed position, and the printer inks are jetted or sprayed onto the textile by the print head. DTG typically requires that the garment be pre-treated with a PTM or pre-treatment machine, allowing for the following:

• Stronger bond between garment fibers and the pigmented inks

• Flattening of loose fibers to provide a smoother substrate

• Chemical reactions with the inks that promote drying and curing

Since this is a digital process, the print is sharper and has a higher resolution, or DPI of 300 min, than traditional printing methods such as screen printing. Unlike screen printing, there is no long setup or clean-up process, and DTG printing has the ability to print a single shirt for minimal cost.

DTG printers use aqueous textile inks (water-based chemistry) that require a unique curing process. Since D2 inks are water-based, they work best for printing on natural fibers such as cotton, bamboo, hemp, and linen. In addition, pre-treatment is typically applied to the garment before printing. The pre-treatment is heat-pressed into the custom t-shirt causing the fibers of the shirt to lay down.[2] The pre-treatment also allows the water-based inks to bond more fully to the garment. This is especially important when using white ink on dark garments.

Once the custom garment -for instance a t-shirt- has been properly pre-treated, the shirt (or garment) is then positioned onto a platten system designed to hold the shirt in place. The shirt is then digitally printed according to the design in the printer queue. 

Hybrid printing combines a screen printed white underbase, and then the machine digitally prints the colors on top. After screen printing the white ink, the pallet rotates under the hybrid digital squeegee print head and CMYK is printed, often times wet-on-wet over the white ink. By screening the white underbase and digitally printing CMYK, hybrid printing is up to four times faster than DTG. Furthermore, the screen printed white underbase reduces digital ink costs because the screen print underbase is pennies compared to digital white ink.

By using a digital print head to decorate your garment, printers can get screen print photorealistic images and complicated high color t-shirt jobs from only making one screen. Hybrid printing can also print “variable data.” This means that a hybrid screen printing set up can change wording and even the final design image from t-shirt to t-shirt without stopping or slowing down production. The digital ink is printed wet-on-wet so there is no need for flashing in between. Compact digital hybrid printing systems do not require any “post printing” afterwards. Just run it through your screen printing conveyor heat tunnel dryer.

Hybrid screen printing is not limited to just cotton. It versatility allows screen printers to digitally print on most any fabric your customer wants. You no longer had to steer customers to 100% cotton as previously for DTG printing. Digitally print any fabric you can screen print - this includes popular polyester and other synthetic materials.

Every now and then ink will get on a garment where it is not supposed to be. Before any print run always ensure that your hands are cleaned of any wet ink. (Use the orange Gojo hand cleaner before every job). Do not try to remove large amounts of ink, always try to save as much cured ink remover as you can.

• Using a cup or a vacuum arm make sure there is an open space behind the area of the garment you are trying to spray out. Adjust the nob on the end of the gun as needed and slowly spray out ink until it is fully removed. Be careful not to spray to close to the garment, this can result in break down of the garments stitching.

• Always wear gloves and be in a well-ventilated area when spraying ink out of a garment.

• Any pigment dyed garments such as comfort colors cannot be sprayed out. The cured ink remover will bleach the garment. Certain fabrics with heat resistant and water proof coatings will not be able to be sprayed out either.

At Brist we operate both manual and automatic screen printing presses. We choose to use these presses depending on job size, number of ink colors, and the placement of the design. Screen printing presses allow for us to set up multi colored jobs with perfect registration in order to print a full run of garments with precision.  

Refer to the Brist M&R Guide for full operations and the Sportsman Ex Automatic Press. Every job is different from each other, each new print will have its own specifications that will have to be set up on the press.

Manual Press: 

Our manual screen printing press is generally used for low quantity jobs with minimal ink colors. This is because each color must be printed independently by the operator. We would also choose to use the manual press when the print placement is in a unique area of the garment which requires more time to load each item. Using the manual press on these jobs frees up our automatic presses for larger orders that require more colors. 

Automatic Press:

Our automatic screen printing presses are generally used for large quantity jobs with multiple ink colors. In order to run the automatic press efficiently, it requires one operator to load the garments at one location, and another operator to off load the garments at the second location. Each head on the press prints a single color automatically. The more heads the press has, the more colors can be printed with one revolution. Our automatic presses are able to print as many as 800+ t shirts per hour. 

Video on Screen Printing Presses:

Watch the video below to learn more about Automatic and Manual presses :

Always pay attention to how many screens/separations are used for each design. The SKU Number and PMS colors for each job are located at the top of the screen, above the registration marks.

• TRAP/CHOKE: is a term used during printing which explains how every screen overlap on top of an under base. The under base should always be slightly smaller than the other screens which allows for easy registration.

  • In many cases the outline of a design will have a larger Trap than the rest of the colors, to clean up and create a clear image. The outline screen should always be printed last. (In most cases this is usually the screen with black ink).

• When setting up a new print order, always print the least amount of surface area, to the most. Not including the Under Base (This should always be the first screen). Always register each screen to the under base. The base is the main screen for every print.

• During the registration process, you will have to make various adjustments to the press for each screen and the type of ink that is being printed on each arm.

  • Some inks are much thicker than others and print differently depending on the climate. Inks tend to clump up and stay thicker during the colder months compared to the warmer seasons.

  • Thicker inks tend to have more plastisol in them compared to thinner inks. Some of these include: White, Golden Yellow, Maroon, Navy and Brown. If the ink is too thick to push through the screen mix W.O.W thinning agent to the ink.

• Each ink will have different pressure adjustments, which are located at the end of each arm on the press. Pressure adjustments are also located above the flood bar and squeegee.

  • INK SHOULD BE SKIMMED ACROSS THE SCREEN NOT SMASHED.

  • Standard pressure for most prints should be between 50 and 60psi.

  • Standard squeegee speed is normally set at 4-5 with a flood bar speed always at a 10.

Flash Units: Each automatic press in the Brist shop has two M&R Red Chili flashes attached to each of the presses.

• Most jobs on a day to day basis are plastisol inks so the settings on the flash units are rarely adjusted. The settings of the Temperature and Power on the flash units will have to be adjusted for water- based, discharge, and special effects inks.

• The Standard curing temperature for flashing plastisol is 220 degrees, with a power of 100.

  • The Temperature is adjusted under F1 and Power under F2.

• For the best quality print each flash unit must have a “cool down” station after the flash. It is important the flashed ink is cooled down before the next color is printed.

• The flash times are connected to the Quartz timers on the Automatic Press.

• Pay attention to what type of garments are going under the flash unit. Some garments are more sensitive to heat such as, Tri- Blends and 100% polyester garments.