Dye transfer
Not a spill. Colour walking off one material onto another under pressure and friction, and on pale leather a manufacturer says it WILL happen.
In detail
Dye migrating out of one textile and into the surface it is pressed against. The commonest domestic case is dark denim against a light sofa, car seat or handbag, and the mark appears where contact and movement are greatest — the front edge of a seat cushion, an armrest, the bolster of a car seat. A vehicle manufacturer treats it as certain rather than possible: dye transfer WILL happen any time a natural fibre — cotton, silk, wool or suede — comes into contact with leather, and the lighter the leather, the sooner it shows. That makes it a maintenance interval rather than an accident — the maker's conclusion is to clean leather regularly so dirt does not affect the top coat, not that transfer can be prevented. It is hard to remove for a reason worth understanding: this is a dye doing what a dye does. It has an affinity for the material it moved into and is now IN the finish rather than on it, so aggressive attempts take the finish off before the colour. One related warning from the same bulletin, easy to overlook: newspapers and garments may transfer colour to a vehicle's interior, so it is not only clothing that does this.
Why
- Dye transfer is explained by Dye migration and colour bleeding
Sources for this page
Sources
General Motors LLC, published via NHTSA · Manufacturer documentation
Relied on for: That dye transfer will happen any time a natural fibre such as cotton, silk, wool or suede contacts leather, that the lighter the leather the more quickly it appears, that leather should therefore be cleaned regularly so dirt and grime do not affect the top coat, and that newspapers and garments may transfer colour to a vehicle's interior. (states this directly)