I was browsing DAGuide's blog.... I think this will be of some help: From :
Direct-to-Garment, Sublimation, Digital Transfers, Software & more for Apparel Decorators
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When you use a
dtg printer to decorate a
dark garment, you will want to create a
white underbase first and then print the
CMYK colors directly over the
white underbase. The
white underbase will block the color of the garment from altering the
CMYK colors of the graphic. However, we need to make sure that the
white underbase remains on top of the shirt fibers to properly block the
dark garment color from coming through the underbase. To do this, we will spray or coat the shirt with an adhesive-like substance called
pretreatment. The
pretreatment allows the white ink to remain on the top of the garment fibers and also helps bind the white ink to the garment’s fabric. Think about pretreating a shirt in a similar fashion as you would put primer on the walls in your house before you paint them. In fact, water-based primers like Killz at your local paint store is an IRC coating that was discussed above and can be used for printing on to hard substrates.
Most of the challenges for a new
dtg owner is knowing how to properly apply the
pretreatment to the garment. A lot of these problems arise because there is no single best way to pretreat a shirt. You can go to different
dtg manufacturers and get completely different processes. In addition, the
pretreatment process will change depending on the type of fabric (i.e. cotton, 50/50,
polyester,…) and the color of the fabric (black, red, white,…). I believe the best approach for new owners is to try several different methods and perform their own wash tests to see which process works the best for them. Most
dtg manufacturers and distributors are recommending to new owners to expect to practice on approximately 72 shirts before they become proficient in the process. Ask your
dtg manufacturer what
pretreatment steps they recommend and below are some links to other
dtg owners methods:
- YoDan’s Method -
Inkjet Garment Printing - Screen Printing University • View topic - My Method to This "Madness"
- PinkFreud’s Method -
Inkjet Garment Printing - Screen Printing University • View topic - T-Jet is King
- Sunnydays’ Method -
http://www.t-shirtforums.com/direct-...tml#post309438 PRINTING TIP: When conducting your own pretreating and wash tests, I recommend you keep a log of all the settings used on that sample, including, but not limited to: % of pretreatment, % of distilled water, time / temperature / pressure for curing the pretreatment, settings for both the white underbase and CMYK layers of ink and the time / temperature / pressure for curing the ink. Identify each shirt in your log by putting a mark on the tag of the shirt or write on the shirt with a permanent marker. You will want to use both sides of the shirt as well. This way you can refer back to the log to determine what the exact settings gave you the best results. You will also want to do these tests on different types of fabric and different colors.
In addition, some
dtg owners are now using either a special type of
pretreatment or water-down
pretreatment on light colored garments or substrates to get brighter colors and better wash fastness. For more information about this, click on this link -
FastColor or
Light garment pretreat. Recently, some of the
dtg manufacturers have begun developing and selling of automatic
pretreatment machines to make the process of pretreating more of a science, rather than an art. These machines are rather new and probably need to have more production-type testing done to them. However if you would like more information on them, click on the links below:
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NEW Pretreatment Machine that is ACTUALLY OUT...not coming soon.
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Re: Pretreatment Tips?
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Inkjet Garment Printing - Screen Printing University • View topic - A sneak peak at the Belquette Pre-Treat Station
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Inkjet Garment Printing - Screen Printing University • View topic - Sources of Pretreatment / Makers
Pre treatment 
