How to Print on Transparency Paper for Screen Printing

So, you’re looking to venture into screen-printing but are scared of the whole process of printing on a transparency films and just don’t know how that works? Well, chill out, you’re not alone.

Most screen printing gurus felt that way at first. Today, we’re here to explicate the process step by step. By the time you’re done reading this post, you will be amazed to know the process is not that complicated after all.

So, what’s a transparency paper?

A transparency paper is simply a thin sheet of translucent, flexible material onto which you can draw images and transfer them to a screen coated in a photo emulsion by exposure to light.

When the light hits, the emulsion hardens and the parts of the screen covered by black ink stay soft and you can wash them out effortlessly with water. A detailed design is left on the screen, and you can transfer it onto your fabric.

Doesn’t sound much like a piece of cake, does it? Don’t give up yet, we’re here to take you through the process step by step, and at the end of it, you will realize how simple it really is.

Steps to Printing on Transparency Paper for Screen Printing

(1) First, you need to pick or create a design, and convert it to black and white. Keep in mind that images that are already black and white will not work and neither will gray scales and colors. Also, halftones will work only if the dots aren’t too small.

(2) Use a photo software to edit the images. On the software, click the ink icon and position the cursor on the black part of the design. G, B and R ought to all be 0. Next, position the cursor over the white area, and ensure that the G, B and R are all 255. Once you finish doing this, the image is now ready for printing.

(3) Now, log your image onto a word doc and resize it based on how big you’d like your design to be. Ensure that you are working with an image that is big enough to stretch as much as possible prior to pixelation. If you can spot the pixels, then the printed image will be great on your fabric as well.

Transparency papers normally have a smooth, slick side, and a textured/rough one. Ensure that when you load the paper into your printer, the rough side is the one that gets printed.

The slick part of the paper prevents the ink from drying. If you find it hard to distinguish the printable side of the transparency paper, gently dab one of its corners with water. The printable side will feel a little sticky. 

(4) Before you proceed to printing on the paper, be sure to set the printer to its highest or best DPI (dots per inch). Most of the time, you can just print the transparency paper under the typical paper setting but sometimes you’ll need to choose “specialty paper”. Some printers also have the “transparency paper” setting.

(5) As soon as the transparency paper is printed, let it dry for a few minutes before using it.

Tips to Help You Make Better Transparency Papers for Screen Printing

(i)  The lines have got to be solid. If you’re designing your image by hand, don’t use pens or markers that leave jagged edges. If, however, you’re doing it on the computer, do not work in the RBG color mode but rather use bitmap or greyscale without anti-aliasing.

(ii) The ink you use needs to be dark. The dark color helps block the light. You ought to use black color regardless of the ink color you’re looking to put in the screen to come up with your final print.

(iii) The easiest way of designing your image is to do it on the computer, and here are a few advantages to support this:

  • Making modifications is extremely easy. You only have to click a few buttons on the computer and print a new transparency paper in case there are errors.
  • You can easily save a copy as backup in case something happens to the transparency paper.
  • You can store your design on your cloud storage site like Drop Box or Google Drive and access it from anywhere; you’ll have your design even if you’re miles away from your computer. This is not only convenient but also safe.

Here are several considerations to make when designing your graphic:

  • Size
  • Degree of detail
  • Type of ink
  • Color of ink
  • Type of fabric to be printed
  • Variation of the degree of detail in the design
  • Complication of the graphic

Size

Before you design your graphic, remember that different screen printers come with different transparency film sizes. Some, like the Merchmakr kit come with 8.5" x 11" image areas, while others, like the Merchmakr system, come with larger image areas of around 11" x 11" and with a little dexterity, you can push it out to around 12" x 12". Nonetheless, pushing that size will leave you with very little room to work the squeegee. Fortunately, there are a few ways in which you can achieve great results even with large sizes:

  • Use bigger transparency papers and bigger printers too.
  • Paste up a few transparency papers together. Be observant of how they overlap.
  • Tile the design as you print, assuming the strategy of printing sections of the garment as you go.

Degree of Detail

Note that images with more detail are harder to pull off than bold-type images with thicker lines and bigger dots. If you’re looking to make your work easier, come up with a design whose lines are thicker than a pencil lead and whose fonts are greater than 12 points. Some screen printers can handle a higher degree of detail but the further you wander from the easy mode, the more expertise you will require to print that image.

Color of Ink

Different ink colors have different traits. Lighter colors tend to be more viscous than darker ones, making them more difficult to print. Sometimes, you can just move to lower mesh screens, like 100 mesh (if the degree of detail in your image is low) to make the printing process easier.

If your ink is transparent or a little clear, you might have to apply an underbase or a double print to help it show up on darker fabrics. An underbase is simply a layer of white ink or any other light-colored ink that you can print as a base on a darker-colored garment for other colors to sit on. It, generally, masks the dark color of the garment.

Type of Ink

There are 2 main types of ink that screen printers use – plastisol and waterbased inks. Let’s examine them quickly:

Plastisol Ink

This is the most popular ink the US, probably because of its ability to sit on screens for long periods without drying and its high opacity too. Other factors that have contributed to its popularity include high flexibility and durability. Specialty plastisols are likewise popular and frequently sold off as bases and additives.

Plastisol ink is a thermoplastic (made up of PVC materials dangled in plasticizing emulsion), and thus it doesn’t penetrate the fabric deeply. In that regard, it’s opaquer on colored garments than most other inks. Plastisol sits on textile materials and gives the design a ‘plasticy’ feel.

Plastisol ink doesn’t dry until it’s cured with high heats of around 325 °F. That means that you can leave it in the screen for a long time and it won’t dry or ruin the mesh. You could even scrap it off and return it to the container for re-use. Also, the ink is very user-friendly and you can use it right out of the container.

Although this type of ink appears to be perfect, it’s associated with a few drawbacks too. Being a thermoplastic, it melts when it comes into contact with items that are very hot, such as a hot iron box. That will make the design to smear over the garment, thus ruining it. The design will be safe in your ordinary dryer though.

Plastisol ink is very popular among screen printers particularly because of its ability to stabilize even after adding additives. Common additives for plastisol ink include:

  • Puff ink – raises the ink off the fabric, giving it a 3-dimensional look and feel after the curing process.
  • Glitter ink – usually made of metallic flakes, this additive gives the design a sparkle effect.
  • Nylobond – this additive makes it possible for you to print onto waterproofed surfaces like nylon.
  • Suede – gives your design a suede-like touch.

Pro tip for using plastisol ink – don’t use a wooden stick to mix the ink, as the wood will absorb the plasticizer out of it. Consider using a stainless-steel spatula instead.

ii. Water-Based Ink

Though water-based ink is a little less popular than plastisol ink, it’s actually the perfect option for placing darker colors onto lighter-colored fabrics. This ink can also come in handy when placing large designs onto large fabric areas where the feel is crucial.

Water-based ink penetrates the fabric more deeply than plastisol does, and therefore it gives your design a much softer touch. The ink cures at around 225 °F and unlike plastisol, it can be air-dried.

What if you’re looking to print on darker-colored garment? That’s okay, discharge ink, which is a type of water-based ink, will cut it. 

iii. Discharge Ink

Discharge ink is a water-based ink variety that produces a soft design; it’s used only with dark cotton fabrics. This ink contains activating agents and pigment components. The activating agents bleach the garment to its natural fabric color, while the pigment components dye the bleached fabric. Discharge ink cures at around 225 °F but it too can be air-dried. 

The bad side of discharge ink is that after mixing it, it remains viable for up to 8 hours only, and therefore it can be more wasteful than plastisol ink. Also, it’s not very user-friendly, and in that regard, you have to use it in a properly-ventilated area. If you have to touch it, you have to wear gloves to avoid contacting the dangerous chemicals in it.

We’d recommend that you use plastisol ink, especially if you’re thinking of a DIY job. That’s because plastisol ink is safe (doesn’t contain dangerous chemicals), it’s not wasteful as it can sit for long periods without drying, and you can re-use it, thus making it a very economical option.

(e) Type of fabric

When considering the easiest fabric to print on, cotton will often be your best choice. Other people prefer a blend of cotton with other fabrics, especially polyester. Whatever fabric you choose, we suggest testing your ink for suitability first, especially if you’re working with a critical garment. For fabrics that don’t contain cotton, you will most likely require special inks.

Remember, additives can help change the properties of your ink, increasing or decreasing its opacity, and even influence the degree of detail you can achieve in the design you’re creating.

(f) Variation of Detail Level in Your Design

If your design has high variation in the degree of detail in it, that can spell trouble. For instance, if some zones appear great with just a little ink deposit while other zones appear better with a heavier deposit, you might want to modify the design or use separate screens even though you’re working with just one color.

Normally, huge color fields with thin ink deposits will appear spotty. On the other hand, thin lines and small fields that are close together will blur if heavy ink deposits are utilized. Having both fields on the same screen will only make your print more difficult.

Final word

As soon as you’re done working on your design on your computer, add registration marks in the top, bottom and center of the graphic to make correct placement of the transparency paper easier.

With most printers, the transparency should be printed on the “mirror image” setting. Basically, the printing should be done backwards. You will want to make the image as dark as possible. You can experiment with your printer until you’re able to get your darkest result.

Once the film is printed, hold it in light and look for any faint spots. In case you’re looking to go pro, an inkjet printer with black ink in the cartridges will help you do a very fine job.

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