There’s a lot that is the same about printing light and darks for DTG. Shirts must be 100% cotton. The artwork needs to be submitted in the same way. The ink on the shirts must also be cured whether the tee is a light or dark color, so what’s the difference? The main difference is a step in the process called pre-treating. Only dark t-shirts get pre-treatment.
Pre-treating is spraying a starch like liquid substance on the garment, then heat pressing the tee to dry. The liquid acts as a substrate primer for the white underbase. Without pre-treating the white under base print sinks into the shirt and neither the white or any CMYK print colors on top are visible.