What kind of dyeing is the 'pigment' mentioned in the description?

Looking at the material description word by word, each has a different nature. 16-count refers to the yarn thickness, single indicates the structure in which the fabric is woven, and only pigment relates to color.

Pigment refers to coloring matter. Unlike dyes that penetrate deep into the fibers, pigments sit on the fiber surface and are attached with a fixing agent. Therefore, as you wear and wash it, the pigment on the surface comes off little by little, and the color fades and the tone changes, starting from areas that are folded or rubbed against. This is why it looks somewhat well-worn even though it is a new garment.

This T-shirt has additionally undergone bio-washing on top of that^[2]. This is a process that cleans up fine fuzz on the fabric surface using enzymes to soften the texture and calm the color tone.

For care, you can approach it knowing that the color sits on the surface. In general, pigment-dyed products can lose color during the first few washes, so it is safer to wash them alone, inside out, in cold water, and for a short cycle. It is better to avoid bleach, strong friction, and prolonged soaking.

hmmm, the single word 'pigment' is close to a notice that this charcoal is not a color that will remain in its initial state.