"Trans-par-ent" - is
When it comes to DTG printing, DTG printers do not print transparent colors and this is due to the pigment based inks they use. When our DTG printers attempt to print transparent colors, the ink doesn't spread and on dark garments the white underbase will show through.
The best way to check your art files, would be to import your artwork into your favorite graphics program and turn off your background layer. If you can see the checkered background behind your image, it is transparent.
If you need more information, have additional questions or just can't find the answer to your question here, please submit a support ticket and one of our account managers will be happy to help.