Leather hides in the tannery sorted ready for dye...
The hides are sorted into colours because darker dyed hides (black etc) can have more visual imperfections, with the dark dyes covering these flaws.
Lighter finished colours (tan etc) demand hides that are much clearer of visual flaws.
When the hides are used in the colour shown in the image, which is called natural, they have to be the clearest skins available, unless you are making scars etc part of the design.
Now you know!
