What kind of processing is the garment pigment washing mentioned in the description?

The order of applying color is different. While standard dyeing fills color all the way to the inside at the yarn or fabric stage, pigment washing is a method where large pigment particles are placed on the fiber surface and then washed out with water. When 'garment' is added to this, it means that the dyeing and washing processes were carried out after the garment was completely sewn and finished, rather than in the fabric state.

Texture remains along every seam. Because the pigment does not penetrate deeply into the fibers, the color around seams or seam allowances that experience significant friction washes out first, creating subtle shading. Instead of the stiffness typical of new clothes, a naturally faded texture—as if washed multiple times—runs across the entire garment.

WELTER EXPERIMENT applied garment pigment washing to both the BLACK and BEIGE options chosen in the CONTRAST LONG SLEEVE T-SHIRT^[1][2]. Because it has already undergone the process of washing and drying after the garment was completed, there is less fabric shrinkage or twisting that occurs with wear.

hmmm, it is a processing that wraps natural light and shade around the edges and seams of the garment, instead of a smooth solid color.