Tips for Printing 100% Polyester Shirts

Tips for Printing 100% Polyester Shirts

Tips for Printing 100% Polyester Shirts

Tips for Printing 100% Polyester Garments with Image Armor LIGHT
One of the hottest markets for printing is the sports performance fabrics markets commonly known as 100% polyester garments. For the DTG printer, these are extremely difficult fabrics to print because the nature of the fibers is to “wick” moisture away. Considering that the inks we use are water based inks, this obviously creates a problem and causes the image to not be as bright as it could be resulting in the ink “wicking” and the image to become blurry. Another problem is that the images on untreated 100% polyester fabrics don’t hold up well in the wash.

Image Armor LIGHT Shirt Formula changes all of that for the direct to garment printer. Image Armor LIGHT allows formerly unprintable or hard to print 100% polyester fabrics to be more receptive to your DTG ink. This results in incredibly vibrant and wash fast garments.


1. Pick the correct shirts to try to print on. Not all 100% polyester garments are created equal. There will be some testing required, however, keep in mind that currently 100% black and dark polyester printing is still not quite “market acceptable”. Our Image Armor LIGHT is designed for use on 100% polyester white and some light colored garments.  We recently had a customer utilize a safety green and a bright pink polyester sport shirt that pretreated and printed great for them. Sometimes the pretreated areas on colored polyester shirts may leave a “haze” or window where the pretreatment was applied. You should not see this on white polyester. Testing is required prior to any production run.

2. You may need to adjust your colors. Image Armor has a tendency to make the image look brighter and colors darker (like Black) due to the effect the pretreatment has on the inks. the LIGHT formula enhances the color spectrum and brightness. After you’ve printed a few shirts with Image Armor LIGHT you will get a feel for any adjustments you might need to make prior to hitting the PRINT button.100-percent-polyester-bleed-through

3. More than likely you will need to use a slip sheet. A what? A slip sheet is a piece of paper or something that is placed on the inside of the shirt prior to printing. This keeps the ink from passing through the front of the shirt and ending up on the inside of the back of the shirt.

The reason this happens is that your DTG printer can not print on air. If you hold your polyester garment up to the light you will see that the weave of the shirt most likely leaves a fair number of air gaps between threads. Your ink has to have something to grab onto and that “something” is the fibers of the shirt. If there’s no thread, the ink drops through the top of the shirt onto the next layer below it. In the case of the photo above it was the inside back of the garment. This is the same reason we have problems printing solid white ink on dark polyesters. The white ink is not able to bridge the air gap between the individual fibers in the weave of the garment causing a visual effect of the ink “fading”.

4. Make sure when heat pressing your polyester shirt it is flat. If polyester fabric is heat pressed with a fold in it, it will be there forever. Always make sure that both layers of your garment are flat on the area that will be pressed. This is especially important for heat presses that do not allow you to “thread” the shirt onto platen. Failure to make sure it is flat will result in permanent visual marks where the fold was located.

Many people have given up printing 100% polyester fabrics with their DTG printers just because the images looked faded, they did not wash well, and the ink bleed making the print fuzzy. With Image Armor you can find a new source of work for your DTG printer and expand your business for 2014. Find out why more and more DTG printers are printing 100% polyester and 50/50 white and light colored shirts with Image Armor LIGHT.

Sublimation looking prints on 100% white polyester using Brother DTG inks

Sublimation Like Prints on 100% Polyester With Brother Inks

White Polyester CMYK Ink print with Brother Inkset100% White Polyester Printing on Brother DTG
If you want to get sublimation like prints from your Brother direct to garment printer, it is now possible with Image Armor.We used a Sport-Tek 100% polyester shirt and pretreated with Image Armor (18 grams in this example) and the results were absolutely incredible – rivaling that of sublimation at a fraction of the cost of sublimation.

We did absolutely nothing different in the printing process with this print. As you can see in the image below that the left side was NOT pretreated while the right side was pretreated with Image Armor Dark Shirt Formula. The pretreatment was then heat set with two presses at 330F for 20 seconds each at a light pressure. The light pressure keeps the traditional lines from the paper and heat press from permanently being set into the fabric of the shirt (this is a well known issue with sublimation leaving transfer paper marks and heat press marks in the fabric). The shirt was printed on a GT-541 garment printer with a vivid setting of 3 and then heat set for 35 seconds at 356F. You can see the image below there is a VERY significant different between the left side and the right side. The treated (right) side has a very significant color intensity vibrancy as compared to the straight print on the left side with no pretreatment.

Brother GT Polyester Print split shirt

What this means to you is that if you own a Brother series direct to garment printer you will find that you can seriously expand your sales into the performance fabric market. Obviously you will still need to do some testing as various polyester types may behave differently and perform differently, however the results are well worth the effort.

You can find a dealer for Image Armor near you by checking out our PURCHASE page.

Update 10/31/13: 15 Washes and Drying

Below is a picture of the 100% polyester shirt form above that was printed with a Brother printer using JUST CMYK inks and our Dark Shirt Formula. As you can see, 15 washing and drying cycles and the image still looks almost like the original un-washed version. This definitely gives your sublimation a run as a viable alternative solution.

Image Armor with Brother GT Ink on 100% white polyester fabric

100 Black Polyester 10x washed shirt

Why is Polyester So Hard to Print with DTG?

Black 100% Polyester on Anajet Prior to heat curingThe Holy Grail
In the world of DTG white ink printing, 100% dark polyesters seem to be the Holy Grail. If only we could….In reality, polyester printing is a lot different than printing 100% cotton shirts. Most of the inks on the market today are designed to work with organic, 100% cotton garments. And they work really, really well. This is great if you are just printing 100% cotton. Our Image Armor Dark Shirt Formula (for 100% cotton shirts) has proven to raise the bar by improving wash ability by up to 50% or more while blowing the application window wide open.

Previous pretreatments required you to apply just the right amount on the shirt to get acceptable wash results. Too much and the print looked great, but would wash off quickly once the customer took the garment home. Too little and the white ink was weak and didn’t wash well either. Image Armor has opened this application window gap by completely re-writing the formula for white ink DTG printing. This makes it much easier for newcomers to achieve success with their white ink printing attempts.However, polyester still remains “unattainable”. Even though Image Armor Dark Shirt Formula works well with white 100% polyesters (looks like sublimation and washes as such) and even fairs well on light colored polyester shirts. However, why is it we have issues with darker 100% polyester shirts?

The Reasons
In our testing, we’ve seen incredible results from printing white ink on 100% black polyester shirts. As can be seen in the image to the left, this 100% black polyester shirt looked great on the shirt prior to heat setting. However, after curing the ink the image appeared to fade. In the past, we would have blamed dye migration which is still very much an issue on red or red family dye colored shirts. However, I don’t believe that we can leave all the blame at the feet of dye migration.

Traditionally, white ink would bridge the gap on the shirt and the pretreatment would allow the ink film to stay on top of the shirt as seen in the image below.

100 percent cotton white ink film closeupHere you can easily see where the white ink ends and is sitting on the top of the grey shirt. Also note how tight the weave is for this 100% cotton shirt. This is why you get better prints off of good, high quality ring-spun shirts with a really tight weave and thin thread size. You are basically creating a smooth, flat – think of it as photo glossy paper – surface for the white ink to print on and to which to adhere. The resulting prints are obviously of very high, smooth quality.

Now, let us take a look at a closeup via USB microscope at the polyester shirt. The left image is the original 100% polyester shirt, washed 10 times. You will notice the image does look faded – the white and colors are “muted”. However, take a look at the image to the right. This is a close up of the white print on the 100% black polyester fabric. The “fade”, or color loss, is due to halftoning. This would be similar to what is experienced when you take a 100% white ink film and halftone it 50% – resulting in a “grey” looking print vs a solid bright white (it is after all 50% of the optical brightness). The weave of the fabric is much looser allowing less fabric for the white to totally adhere to creating the illusion of a faded white.

However, the close up reveals much more. The ink is still extremely white and adhering extremely well to the fibers BUT the air gaps in the weave of the fabric (which allows for breathability and is why people like the polyester performance fabrics) leave nothing to which our white DTG inks can “stick”.
100 Black Polyester 10x washed shirt100% Black Polyester White ink CloseUP washed 10X

As can be seen in the image to the right, above, the ink is adhering quite well. However, the open weave of the fabric and due to the nature of polyester, we have a lot of “open” space which allows the black polyester to show through the white printed area effectively fading the actual image vibrancy.

This is part of the reason why we are still having difficulties printing white ink on dark polyester fabrics.

What Does this Mean for DTG Printing in the Future?
What this means is that we still have a ways to go with white ink printing on dark polyester fabrics. However, our goal at Image Armor is to bring you the best possible products. We have already taken 100% polyester printing further than any other company to date. And we have the drive and ideas that we believe will help bring this area of printing to reality.

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