Unlike printing on white or other light colored t-shirts, printing dark colored t-shirts can present certain challenges. There are certain tips and tricks to printing dark shirts.
In this article, we try to cover everything you need to know about printing on darks ranging from the PFP (Print-Flash-Print) technique, to the proper mesh counts, to the time saving “coating stroke” technique.
GENERAL CONCEPTS Multi-color printing on dark shirts will almost always involve the use of an underbase. An underbase (usually printed with white ink) is used to “seal” the surface of the garment and to provide for a white background on which the artwork will be printed.Furthermore, single color printing on dark shirts is best achieved with the use of specially formulated ink known as “super opaque” to achieve the opacity of an acceptable print.
The print-flash-print (PFP) technique can sometimes be eliminated by using multiple print strokes of which the last stroke is a “coating” stroke that will effectively “seal” the print to achieve desired opacity. Perfecting the coating stroke requires a certain mastery of manual screen printing and usually requires the use of special ink formulations.
PRINT-FLASH-PRINT TECHNIQUE (PFP)
When printing on dark shirts more often than not you will need to print the ink twice to achieve the desired opacity of the print. Printing the ink twice covers the fibers in the shirt so you do not see the color of the shirt showing through. To achieve complete opacity of the print you would use the Print-Flash-Print technique (PFP). To use the PFP technique, you print the ink color, flash cure to “dry” the surface of the print, then apply another print stroke. Flash curing times when using the PFP technique will vary depending on the type and color of ink that you are using. Flash curing times for white ink is typically under 10 seconds. When flash curing colored inks you may need to flash the print 20 seconds or more. Moreover, that flash print will become very hot and it may be necessary to use either a cool down station or a “chiller plate” to cool the print before applying your top coat.
Printing on dark shirts that require the use of an underbase will require flash curing. The purpose of the flash curing is to dry the surface of the white print so that the other colors in the image can be printed on top. Almost always you will have to print and flash the white ink twice to achieve the opacity necessary for an acceptable print. When printing one ink color on a dark shirts you will almost always need to use the Print-Flash-Print technique (PFP) which is described in detail above.