The tanning process known as chrome tanning with chromium (III) salts is now used for around 85 percent of global leather production. Compared with vegetable tanned leather has a so-tanned leather is twice as high tensile strength, however, is easier because the chromium salts used for tanning not fill the skin: The tannin makes only up to 4 percent (with newer leathers even only about 1.5 percent) of the leather weight, while lohgegerbtes leather has a tannin content of 20 percent. The tanning process is faster and less material than altgegerbten leathers, which saves costs.
Wet Blue is the freshly tanned leather open-pored, with its characteristic bluish tint. It is globally transportable and can be stored well, so a unlimited international sales and global processing are possible.
"Wet Blue" - damp, gray-bluish leather right after chrome tanning. The chromium (III) salts are considered safe and bring (despite intensive skin contact in the shoe or apparel) only in extremely rare cases difficulties. But is harmful chromium (VI), which may arise in improper tanning conditions in the leather, but which are now explored and can be avoided. Fats with a high proportion of unsaturated fatty acids thus promoting the formation of health-hazardous chromium (VI) in chrome tanning. The best protection against chromium (VI) is the use of appropriate Fatliquor and the implementation of the vegetal re-tanning with quebracho, chestnut, Mimosa or Tara.
In addition, environmental considerations are relevant with respect to the chrome tanning. Doing so, in the tanning chromium-containing effluents and waste that is recycled and must be recycled to recover valuable materials; also at the disposal of chrome-tanned leathers correct operation is essential, as in combustion chrome-tanned leather harmful chromium (VI) is generated.