Cute Young Brunette Girl Reveals On The Red Leather Couch

• Synthetic-tanned leather is tanned using aromatic polymers such as the Novolac or Neradol types (syntans, contraction for synthetic tannins). This leather is white in color and was invented when vegetable tannins were in short supply during the Second World War. Melamine and other amino-functional resins fall into this category as well and they provide the filling that modern leathers often require. Urea-formaldehyde resins were also used in this tanning method until dissatisfaction about the formation of free formaldehyde was realized.
• Alum-tawed leather is transformed using aluminium salts mixed with a variety of binders and protein sources, such as flour and egg yolk. Purists argue that alum-tawed leather is technically not tanned, as the resulting material will rot in water. Very light shades of leather are possible using this process, but the resulting material is not as supple as vegetable-tanned leather.
• Rawhide is made by scraping the skin thin, soaking it in lime, and then stretching it while it dries. Like alum-tawing, rawhide is not technically "leather", but is usually lumped in with the other forms. Rawhide is stiffer and more brittle than other forms of leather; it's primarily found in uses such as drum heads where it does not need to flex significantly; it is also cut up into cords for use in lacing or stitching and for making many varieties of dog chews.
• Leather—usually vegetable-tanned—can be oiled to improve its water resistance. This supplements the natural oils remaining in the leather itself, which can be washed out through repeated exposure to water. Frequent oiling of leather, with mink oil, neatsfoot oil, or a similar material, keeps it supple and improves its lifespan dramatically.