Last updated on July 31st, 2023 at 12:30 am
Denim is made from “Bean dye” with the warp threads heavily covered by starch mixed with indigo or sulphur dye. If you want to print on it the only method you can use, is to use pigment print to cover the dark color of denim. However, when you do that the pigment dye applied is on the surface of the fabric; to make it clearer, it is on the starch mixed with indigo or sulphur dye but not on the cotton fibre. When the printing is done, the printed design may look acceptable without giving you a clue that there is a hidden problem. However, when garments are made from this fabric and washed, you will notice that the printing has disappeared leaving only faint marks where the printing used to be. This is used because during washing the starch is washed away and the printing which was attached only to the starch went with it.
on the fabric after wash. The following are examples:
- 100% of the printing to stay
- 70% of the printing to stay
- 40% of the printing to stay
- 5% of the printing to stay
If you want 100% of the printing color to stay on the fabric after wash, you must do the following:
- Before printing you must desize the fabric very thoroughly. Desize means to away the starch on the fabric.
- The pigment dye must contain sufficient “binder” to make the dye stay.
- After printing you must get the fabric through the “baking process” for sufficient time and temperature.
If you do the above 3 steps thoroughly, the printing will be color fast and remain bright and fresh after washing. However, I’m not sure this is what you need because; usually garment buyers or consumers would not like the printing on denim to be color fast to stay bright and fresh like new. They probably would like 30% or 40% of the printing to go away after washing with 60% or 70% of the color to stay. In such case, the 3 steps as described above must be done to a different extent:
- You still desize the denim thoroughly before printing.
- You still use “binder” in your pigment dyed, but use less amount.
- You still get the printed denim through the baking process but at lower temperature and for shorter time.
For the above adjusted process, a certain amount of the dye will be washed away when the garment goes through the washing process, to achieve the slightly faded look desired.