The primary processes for the manufacture of leather items including leather shoe include preparatory stage, tanning and crusting.
Preparatory steps consist of several processes for removing unwanted materials from the skin, and some of the processes include preservation, soaking, lining, fleshing, unhairing, splitting, reliming, deliming, bleaching, pickling and depickling.
Tanning: In tanning, the protein of the rraw sking is converted to a suitable stable form so that the finished leather can be used for any purpose. Chromium is conventionally used for tanning and after treating the raw skin, it becomes pale blue in color and hence it is also called as “wet blue”.
Crusting: For making the skin thin and for drying and softening some chemicals are added, and it is called crusting. Depending on the end use, some sub-processes including wetting black, saying, whitening, shaving, neutralization, splitting, dyeing, filling, stuffing, setting, fixation dry and conditioning are used.