Also seen on Impressions
We are creeping up on October and there is nothing like a good ghost story to make your hair stand on end. The ghosts in our story aren’t souls of the dearly departed, but they will haunt you none-the-less.
Say you printed an order of shirts, boxed them and sent them on their way. Nothing was out of the ordinary during your print job so you go on the rest of your week as usual. Then your customer calls about their shirts and complains that YOU did something wrong and their shirts are ruined. When you get the shirts back you notice a silhouette of the image printed on the backs and bottoms of each shirt. Sounds like you have a ghosting problem.
Not real ghosts though. The Ghost Busters aren’t going to be able to help you out with this one, but luckily you aren’t the only one plagued by this epidemic. Ghosting is a problem that every screen printer will probably run into at least once in their career.
So what exactly is happening here?
Ghosting is the disappearing, or fading of the garment’s color, directly under the printed area of stacked garments. This typically happens when printing a low bleed white on a colored shirt. There is always the possibility that the colored dye of the garment will come through the white ink printed on it. It is very tempting to use a low bleed ink to prevent any dye migration from occurring, but in fact low bleed ink rarely stops the “bleeding” that occurs during dye migration.
Ghosting can occur for a multitude of reasons which makes it all the more maddening. Here are a few reasons you might experience ghosts haunting your garments:
- Excessive PH left in the garment from the manufacturer
- High humidity in the shop
- Moisture in the garments
- Certain garment colors
As mentioned, certain colored garments can trigger ghosting. Colors like light blue, yellow, green and violet are all offenders. Your dryer can also be a part of the problem. If it has a short heat chamber, there is less time for moisture to evaporate for the ink to cure. If you try to run the belt at a slower speed and crank up the heat then the shirts are coming out at a really high temperature. Stacking the hot shirts can contribute to ghost images.
As with any of the issues that may arise in your shop, they are typically solved by going back to the basics of screen printing. Having the right mesh, good squeegees, proper off-contact, and good screen tension are best practices when printing. Make sure that you use the appropriate ink for the job. 100% cotton calls for cotton ink like 50/50 blends calls for low-bleed ink. Keep moisture and humidity low in your shop.
Consider pulling the shirts out of the box and running fans or the air conditioning to allow any moisture to evaporate. If you have any concern that your garments may be susceptible to ghosting, avoid over flashing or over heating the shirts in the dryer. You want to cure the ink properly, but stacking hot shirts will cause the colors to distort due to the dyes in the garment.
Like any of the ghost hunter TV shows out there, there are tests that you can use to determine if your garments are haunted – no Ouija board needed.
- Print your ink onto a piece of the same fabric that will be used for the order.
- Take your test piece and place it in a heat press. Spray with a light mist of water for moisture.
- Cover the printed area with a blank piece of the same suspect fabric (sandwiching the print). Set the heat press to 250F.
- Close the heat press and let it sit for a half hour before visual evaluation.
- After a half hour, check for ghosting on the unprinted piece of material.
If the material is prone to discoloration, you will see a ghost image of your printed image on the material that was covering the printed area. Spooky!