Diluting the Pre-treatment Solution

Before applying the pre-treatment solution to a T-shirt, make sure you dilute it correctly with distilled or purified water as described here.
Caution:
If you do not dilute the pre-treatment solution, it leaves noticeable traces on the T-shirt or the printed surface cracks after washing. If the pre-treatment solution is too weak, White ink does not adhere to the fabric and the desired whiteness cannot be achieved.
When fixing ink with a heat press
Garment color Dilution ratio
Black/dark colored garments Start with 1:2 (pre-treatment solution:water) and test increasing water up to 1:6)
Pastels/light colored garments Start with 1:1 (pre-treatment solution:water) and test increasing water up to 1:3)
Note: Use pre-treatment solution that is diluted more than 2 times if uneven colors occur after fixing the ink (such as layering color ink over White ink), or when pre-treatment solution leaves a trace.
When fixing ink with a heat tunnel
Garment color Dilution ratio
All colors Start with 1:2 (pre-treatment solution:water) and test increasing water up to 1:3)
Related references
Fixing the Pre-treatment Solution (Heat Press)