Proper Application of Pre-Treatment

Brian Walker started in the screen printing industry in the mid-1980s while still in high school and has since been involved extensively with the direct-to-garment printing market. Currently, he is the CEO and owner of RTP Apparel and Image Armor. RTP Apparel provides pretreated T-shirts to the DTG industry. Image Armor is a DTG solutions provider that manufactures inks and pretreatments.

Several factors should be considered when talking about the proper application of pre-treatment:

• The right amount of pre-treatment should be applied. This varies from manufacturer to manufacturer and is dependent upon several factors. A general rule is that the lighter weight the shirt, the less pre-treatment (due to the absorbency of the fabric and how the shirt is manufactured). In addition, lighter colored shirts (such as an ash color) typically require less pre-treatment than darks.

• How the pre-treatment is applied can greatly affect the application. Hand-spraying can be done with any pre-treatment. However, most pre-treatments have a “window” of optimal application—that is, a certain amount of fluid that should be applied to the shirt to get the optimal print and wash characteristics. Note that doing this by hand is an art and is often the cause of many issues with wash-fastness. The easiest and most consistent way to apply pre-treatment is by utilizing an automatic pre-treatment machine, which allows for a more consistent and repeatable application. Taking one more variable out of the equation (hand pre-treating) can lead to fewer rejects and returns down the road.

—Brian Walker,, i-Group Technologies

Read more from Brian Walker about the digital direct-to-substrate printing process.