How to Coat a Screen with Emulsion

Posted by Mary Yaeger - 9/18/2017

Also seen on Printwear 

Coating a screen is also referred to as “making a stencil”. The process is done with emulsion which is a thick liquid that is sensitive to UV light. When you place artwork on the photo sensitive emulsion and expose it, a negative stencil is created. This negative stencil is what allows the ink to be printed on a garment.

Before we get into coating a screen we need to discuss the different types of emulsions that are available. There are three types of emulsion and capillary film – which could be used as an alternative to coating the screen. All emulsions work with plastisol inks. Water based inks will eat through most emulsions so you will use an emulsion formulated to work best for water based printing.

Diazo Emulsion

Diazo emulsions have been used for many decades and are still preferred when low production cost is a major consideration. Diazo emulsions are either water resistant or resistant to UV and solvent-based inks. Plastisol inks may be used with either diazo emulsion type.

Dual Cure Emulsion

Diazo-Photopolymer emulsions, also known as dual-cure emulsions, offer the largest variety of features and applications. Dual cure photo-stencil systems provide remarkable image quality and exceptionally durable stencils. These are premium emulsions for use with UV, plastisol, water-based, and solvent-based inks. Whether you need an emulsion with high chemical resistance or one specifically for ceramic inks, our selection provides the right emulsion for your requirements.

Pure Photopolymer Emulsion

Photopolymer emulsions are one-component emulsion systems that are pre-sensitized and ready for use. They offer very fast exposure speed and can be used universally, but often are developed for specific applications and exposure equipment such as direct projection, high emulsion over mesh ratio or for coarse mesh counts. Photopolymer emulsions are typically resistant to UV, solvent-based and Plastisol inks.

Capillary Film

Capillary film can replace liquid emulsion as the technology necessary to meet a wide range of decorator demands, including textured garments, textured prints, and higher resolution images at a lower production cost. Capillary film is not messy like liquid emulsion, does not require mixing ingredients, does not require storage in the refrigerator, and has a longer shelf life. There is no waste, since you cut off and use just what you want.

Application

Emulsionscoop coaters are a must-have tool for coating screens with all direct liquid emulsions. Emulsion scoop coaters are the perfect way to get a smooth, even emulsion layer on your screen.  Simply pour an appropriate amount of emulsion into the coater reservoir then position the coater against the screen and move slowly and smoothly from the bottom to the top, adjusting the angle of the coater slightly as you go to ensure good coverage.  

It is usually best to get an emulsion scoop coater about 2-3 inches narrower than the inside screen frame width. You want the coater to be just wide enough to cover the entire emulsion width in one pass. For heavier ink deposits or to increase the durability of the screen for longer runs additional coatings may desired after the 1st application dries. This will provide a thicker more durable stencil. 

Now, you are going to start with a screen that has been degreased and dried without being contaminated with dust, lint or finger prints. Next, you are going to fill the scoop coater with emulsion. Place the screen frame in an upright position and secure it in place. Use two hands to hold the scoop coater.

When coating screens the emulsion needs to be even on the mesh. Thick and thin places will cause problems during drying and exposing. The thin places will expose faster and cause the image to not wash out due to over exposure. The thick places will expose slower and cause the image to break down and wash out.

There are three types of coating methods:

1&1 Coat – Apply one coat of emulsion on the print side, rotate the screen 180, and apply on the squeegee side. Dry in a horizontal position.

2&2 Coat – Coat twice on the print side, then twice on the squeegee side. After each coat, rotate the screen 180. Dry the screen print side down. This will require a longer dry time, longer exposure time and yield a thicker stencil. This coating method is great for athletic printing.

3&3 Coat – Start by using method 2 above. After complete drying of the emulsion in method 2, add an additional coat on the print side and dry again. This method produces the sharpest edges and thickest stencil and ink deposit.

After coating the screens, let them sit overnight to dry. Screens need to be dry to the touch before exposing.

Advantages and Disadvantages of Plastisol and Water Based Screen Printing

Posted by Mary Yaeger - 8/15/2017

There are two main types of ink that get used for textile printing – plastisol and water based. While plastisol is more widely known and used, the desire for a more eco-friendly shop has brought water based screen printing into the spotlight. What you will find is that both types of inks have their incredible advantages, but they also have a few drawbacks.

To get started, let’s discuss mesh. The mesh count you use is one of the most important factors to consider when printing (no matter what method you choose to print). Here is a short outline of the different mesh recommendations for inks:

• 24-40 mesh for Glitter inks
•  60-80 mesh for Shimmers and thick white underbases
•  86-110 mesh for Metallics
• 110 mesh most popular for light colors such as white ink
• 160 mesh most popular for black ink. It holds more detail than 110, but less ink will pass through the screen.
•  200-230 mesh holds high detail though the ink may need to be reduced. This mesh is great for water based inks.
• 230-305 mesh is mostly used for super fine detail half tones and CMYK process prints. This mesh is also great for water based inks.

Plastisol Ink

Plastisol is the most popular ink in the industry. It is easy to use and promoted as “user friendly”. Plastisol is not water soluble so you don’t have to worry about it drying in the screen. These inks are generally used right out of the container. No mixing needed. Plastisol is perfect for getting the opaque look on dark garments. It is formulated for printing on light and dark garments. Since plastisol does not dry in the screen, there is no worry about ruining a screen or wasting product. Plastisol does not “dry” when exposed to air. Plastisol has to be cured between 280-350F. The greatest advantage of this is being able to reuse the ink for multiple jobs. As long as the ink has not been contaminated by dirt, lint or other ink, the plastisol can be scooped off of the screen and placed back in its container.

Likewise, if you leave the ink container open for several days, the ink will be ready to use when you come back. You can also leave the ink in a screen for several days without worry of clogging or ruining the stencil. Plastisol also has the capability of wet-on-wet printing which means increased production times – saving your shop time and money.

It is generally recommended that you store plastisol at room temperature. This means keeping your shop temperature controlled. If the ink gets too hot (above 90F) there is a possibility it could start the curing process in its container. A big disadvantage of printing with plastisol is that has tends to have a greater hand-feel. This is a disadvantage because most t-shirt enthusiasts desire a vintage look and soft hand-feel to their shirts. Another thing to note about plastisol is that it should not be ironed. The iron could “re-melt” the plastisol and smear ink on your garment.

If you would like to dispose of any contaminated ink be aware that uncured plastisol is considered a hazardous waste and should be disposed of according to your community guidelines. When plastisol is cured, it is not considered a hazardous waste, but make sure you still properly dispose of it.

Water Based Ink

What plastisol can’t achieve is where water based ink steps in to play. Water based inks are great for achieving that vintage soft hand-feel that is desired by most. Water based inks soak into the fabric instead of standing on top. Water based inks are promoted as more “eco-friendly”, but it is important to keep in mind where you are getting this information from. Just because it is labeled as eco-friendly, does not mean that it isn’t free of “co-solvents” that could be petroleum based. The reason these co-solvents are used varies, but one of the reasons is meant to reduce the time and heat necessary to cure the ink on the fabric.

While water based gives most people the look and feel they want in their prints, there are a few factors that deter people from even trying it in the first place. Unlike plastisol which is ready to use right out of the container, water based ink requires a little bit of mixing math. Water based inks start out as two separate products – pigment and base. You have to add the right amount of pigment to the right amount of base to get the desired color. There are also several additives that you must consider for each type of print.

With a name like water based it is easy to assume that curing would be a simple process because in reality all you are doing is evaporating the water to cure. At a craft level, this might not be too bad. Water based inks can air dry, but not in enough time for high production jobs. For shops that are printing at an intermediate to high production level, the dryers that are required for water based inks are typically larger than the dryers used for plastisol. To help the ink cure faster, you can add what is called a “catalyst” to the ink. The catalyst allows for a fast dry time and ensures an even dry over the entire printed area. The disadvantage to using a catalyst is that it greatly reduces the life span of the ink. When you add a catalyst to water based ink the shelf life is limited to 4-12 hours.

Water based ink tends to dry in the screens if not tended to constantly. For this reason, it is important to keep a spray bottle full of water nearby to keep the ink wet. If the ink dries in the screen it will clog the mesh and ruin the screen. It is also important to consider the type of emulsion you are using. Water resistant emulsion is a MUST! Water based inks will melt or eat through any other type of emulsion. This will end up destroying your stencil and setting your print job back.

Screen Printing History and How to Get Started

Posted by Mary Yaeger - 5/26/2017

Screen Printing History and How to Get Started

What in the world is screen printing? Simply, screen printing is the process of using a mesh-based stencil to apply ink onto a surface - shirts, posters, stickers, wood and a variety of other materials. The idea of screen printing arose from the concept of stenciling (and in truth that’s what screen printing is a form of). Screen printing can be traced back to the beginning of recorded history where methods can be found in China as early as 960 AD (during the Song Dynasty).

Screen printing originally started as just another art form. It wasn’t until during the 1960s that you can see screen printing being used for promotional items or propaganda. The 1960s was full of civil rights and social justice movements so there were plenty of opportunities to express yourself and your views. Sharing ideas that turn into movements requires people paying attention, and screen printing provided a method to create stunning graphics that caught viewer attentions.

It didn’t take long after screen printing being introduced to commercialism, before screen printing became a popular choice for artists - the most notable being Andy Warhol.

Today, we are seeing a revival in the screen printing industry as artists are creating new twists to the concept. There is also a call for the industry to become more environmentally friendly with their chemicals and inks. So if you are just starting out in the screen printing business there is a lot of room for creativity and growth and we are excited we get to share that with you!

While we could write a book on how to get started screen printing, we decided not to bore you with that much information in this blog post. Instead, we will discuss some tips and basics to get you started.

Step by Step

This is a general outline used by Texsource staff to explain the process to customers and in Texsource University Classes. If you want a more detailed look at the 16 steps and how to get started screen printing, join us for our Screen Printing 101 class in June!

1. Get to know your client and what they are looking for in the design. Don’t forget to take down their contact information to keep in touch as well as their deposit. It’s important to take a deposit at the start of a project so you can order the materials needed for the print job.
2. Place your material order.
3. Create the artwork and layout for the job you are going to be printing. Some sample art programs you might use are CorelDraw or Adobe Software.
4. Get the artwork approved by the client. This is a really important step! You may like what you have designed, but that does not necessarily mean that your design fits best with what the client is looking for. It is best practice to make sure that your client approves the artwork before moving forward.
5. Complete your artwork separations and outputs. It is helpful, and creates a clean print, when your printed artwork is very opaque.
6. Before you print, be sure to degrease and prep the screen that you will be using.
7. Coat the screens and let it dry.
8. Expose the coated screens. To help prevent pin-holes in your print, keep your exposure unit glass clean!
9. Rinse out the image and set the screens out to dry. The trick to rinsing out the image is to wet the screens on both sides and allow the water to start to break down the unexposed emulsion.
10. Tape and block out the screens.
11. Set your screens and make sure that the artwork is lined up right. If you need additional help with alignment, use a t-square to create a good template to follow for your artwork.
12. Print according to color sequence - light to dark! ALWAYS test before production.
13. Inspect the garments to make sure there are not any unwanted spots. Don’t fear if you find some, there are products to help remove unwanted plastisol.
14. When you are finished printing you can scoop the ink and put it back into the container for future usage.
15. Now you are ready to reclaim your screen. You will start by removing the ink, then remove the emulsion, de-haze your screen, and finally degrease it. 
16. Finally you have made it to step 16! This is where you get the products delivered to the client and receive your payment. Congratulations! 

Guide to the Right Mesh 

It is important that the mesh you select is right for the inks you will be using in your print. Mesh counts range from 40 to 305 and higher! We won’t discuss all of the mesh counts (you will get that in class), but here are a few of the most popular:

86 count mesh is used for printing a bold copy onto dark colored fabrics.
110 count mesh is considered the industry’s “do it all” mesh.
200 count mesh is used for printing onto light colored fabrics.
305 count mesh is used during four color process printing.

If you screen ever gets worn out or torn, Texsource can re-stretch your screens or we have products available for the DIY-er!

Mesh colors are another thing to consider. There is white mesh and gold (dyed) mesh. White mesh is used in lower mesh counts which are typically used for spot color work or large text. Gold mesh is used for counts higher than 200 resulting in a more defined edge and crisper print. The other thing that makes the two mesh colors different is the exposure time - the gold mesh will have a longer exposure time than a white mesh.


Other Things to Consider

Emulsions

There are 3 classifications of emulsions - Photopolymer, Dual Cure and Diazo. All of these can be used when printing with plastisol ink. Photopolymer emulsions are direct emulsions with ultra fast exposure times. Dual cure emulsion is resistant to both solvent and waterbased inks. Diazo is formulated to use with waterbased, solvent and plastisol inks which leads us into the next category - ink selection.


Inks

Ink selection is extremely important for your print job. Not all inks work on every material. Inks can also be particular about the mesh count. If the mesh count is too high or too low it could result in a poor print. I think that with as many colors of inks there are in the world there are just as many categories. That’s an exaggeration of course, but there are still quite a few you will encounter during your screen printing career. Some of the categories you will see are general purpose, low bleed, and super opaque. General purpose inks are generally used for for printing on 100% cotton. If you want to use a multi-purpose ink on another type of material, you will more than likely need to print an under lay.

Low bleed inks are best used for printing on 100% polyester materials or dye migrating garments like athletic apparel. Super opaque inks are high opacity inks designed for maximum coverage on dark colored garments.


After making a decision on those important factors the rest is up to you! Getting into the groove of printing, running your print shop, how you design the artwork - all of that is personal preference and that’s something we couldn’t give you a definitive guide on. The elements outlined in this post were to give you some basic knowledge and get you started. If you want any more details about the process, we highly recommend you attend our Screen Printing 101 class. The people who teach the class are highly knowledgeable, hands-on and excited about sharing this process with you.

Now, it’s time for you to get printing!

Specialty Ink Printing: Glitters, Foils, Glows, Reflectives and More!

Posted by Mary Yaeger - 5/19/17

In the world of screen printing there is an overwhelming amount of inks on the market, and the newer you are to screen printing, the harder it is to decide what inks you should try and which you should avoid - for now at least. Being a more advanced screen printer, although knowledgeable, you still face the challenge of working with multi-color processes and finding the right ink for your next print job.

The variety is what makes the screen printing industry one of the most interesting to work in and be a part of. There is so much growth potential for screen printers. The world of ink is expanding and the demand for specialty inks is out there. We are even starting to see a blend among the print industries. Graphic design has adopted screen printing to develop posters and unique brand packaging. Screen printing has adopted 3D printing to take textiles to the next level. The industry is developing fast especially with people being able to print on the go or at home!

My exposure to screen printing has been limited to a small table top printer that I received one year for Christmas. Being green in the industry, I have had my eyes opened to a million different possibilities when it comes to screen printing - even witnessing an automatic press in action. Today, Texsource-U is teaching a class on how to use specialty inks in screen printing so I thought that it would be appropriate to write a blog article on specialty inks.

My favorite printed tees (as i’m sure some of you would agree) are the ones with quirky little quips that are decorated in some way such as gold shimmers or mounds of glitter (the kind that you find in your hair days later). The shinier it is, the more it catches my attention. But what I didn’t realize was the process for printing those inks was different from any other process. I had some idea that special screen printing inks would be different, but I wasn’t sure HOW different they would be from each other. Below, we will explore some different specialty inks and how to effectively use them for your next screen printing project!

Types of Special Effect Inks

Phosphorescent Glow Inks

Phosphorescent is a glow-in-the-dark plastisol ink which is ready to use right out of the bucket.  This ink is formulated for application to cotton and cotton / polyester garments and novelty items. The glow inks print well on white, but they can also work for colored garments.

When printing on colored garments, it’s best (and recommended) to use a white underbase to really make those colors POP! It is also recommended that you use a 86-110 mesh screen and thick stencil to get the best graphics.

Crystalina

Glitter Plastisols are extremely flexible inks. They provide a glittering texture and metallic-like finish when printed directly on textiles or used in transfers. Glitter inks are available in two variations.

1. Regular Glitter Plastisols - recommended for direct printing
2. Super Glitter Plastisols - recommended for heat transfer printing.

Crystalina is used to produce subtle sparkle effects with high gloss and excellent durability. For printing, it is highly recommend using a 25-40 mesh screen. Mesh counts higher than 40 (15 metric) should not be used as this will limit the inks ability to flow onto the garment and will result in a very spotty, irregular finish.

For stencils you can use any direct emulsion or capillary film. And due to the reflective nature of this ink, it requires a longer curing time and more heat to reach the required temperature than a standard plastisol.

Silver Luster

These inks are very versatile and can be used to enhance graphics or create a unique standalone product. Silver Lustre inks are specially formulated to give maximum coverage, and have been incorporated in the clearest, glossiest plastisol available. Not only do these inks create a dramatic effect, they also have excellent wash durability. These inks can be printed using a 60-86 mesh screen.

Pale Gold Glitter

Similar to crystalina, glitter inks are very flexible to work with. When heat cured, that’s when the glittering metallic finish shines through. These inks take on the finish of release papers like you use during heat transfer printing.

You can print these inks directly on textiles. Another great feature of these inks is that they are lead free plastisol and have great opacity when printing. For printing, it is recommended you use a 25-40 mesh screen like the crystalina. Any count higher than 40 will result in a not-so-great finish.

Puff Additive

Puff additives are formulated to be mixed with General Purpose (GEN) Series inks to give designs a raised or elevated effect. Puff Additive allows you to minimize the number of products you have on your shelf and gives you great results. For best results, you should use a screen with a good thick stencil and a medium to soft squeegee for good ink laydown. Puff additive is especially useful in smaller shops that may not want to inventory a complete set of puff colors.

HD Rubber Base

HD Rubber Base can be used as a high density gloss/clear or as a high gloss overprint to any ink.  You can also add colors to create special gloss images. These inks are an excellent adhesive carrier for foil, special flakes, caviar beads, and other creative textures. They can be used on most fabric types. The “Super Elongation” 110 mesh with 200 micron cap film is recommended if you are going to print with an HD Rubber Base.

Ultra Reflective Ink

Ultra Reflective inks are exactly what they sound like. These inks are easy to print with and create a unique reflective surface. When a garment printed with Optilux ink is exposed to a focused beam of light such as that from a flashlight or headlight, it reflects or returns light back to the light source. You can use these inks to create a novelty item or create a unique decorative tool to increase nighttime visibility of a printed design. To get the best print it is recommended that you use a 160-230 mesh screen.

Silver Foil

The great thing about foil inks is that they are press ready. They provide a bright, non-tarnishing metallic sparkle to any printed garment. The inks consist of a fine shimmering glitter flake in a low fusion, and easy to print base. This is a real plus for hand and automatic printers when it comes to equipment wear and tear.  To get the most out of foil inks it is recommended you use a 86 to 125 mesh screen.

Over Print Clear Gel

Over print clear gel  is a super smooth, multi purpose gloss clear that can be used in both high-density printing techniques and as a flat overprint onto colored inks and textured surfaces. The advantage to using Over Print is that it will create shiny finishes to any design. For this type of ink it is recommend you use a 24-110 mesh screen and 200-600 micron cap film for best results.

Now that you have learned about some of the different inks for screen printing, what inks are you considering trying for your next project?