There are two types of leather: vat-dyed and spray-on dyed leather. With vat-dyed leather, the color is obtained by immersing the hide in dye. With this process, the color penetrates completely through the leather! With spray-on dyed leather the color is "painted" on. While this produces a more even color, some of the natural grain of the hide is lost and overall life of the leather diminished. Normally, a painted-on dye will wear off at the stress points. (You may think this is just dirt build up, but on close inspection the dye will be gone.) Most of the vat-dyed leather I've seen has come out of Europe. U.S. and Japanese manufacturers tend to stick to the spray-on dyed leather.