Step One – Rawhide
The first step is to cure the rawhide, which is what the leather is referred to as after being removed from the animal carcass. The place that cures the leather is the tannery. Here, the remains of flesh and fat are removed via the beam house process, which nowadays is done by machine.
Once these remains have been removed from the hide, it then goes through the liming process, which involves the hide being spun in a large drum with either calcium carbonate or lime. This avoids putrefying of the skin and helps in the removal of hair and any other protein deposits, which can be washed away.
The final part of step one is a process known as de-liming, which removes excess lime. The leather is then enzyme treated to remove remaining proteins and then it’s on to stage two.
Step Two – Wet Blue
The first part of step to involved the hide being bathed in chromium salts, which are absorbed into the skin of the hide, which turns the skin a shade of blue, hence the name Wet Blue.
After this, experienced professionals will examine the hide to check the quality and then categorise it accordingly. The hide will then be separated into layers. The top layer is the full grain leather, considered to be the most luxurious. The second layer is most common in furniture production and known as corrected grain. The third layer is of the lowest quality out of the three known as split leather.
To ensure a consistent thickness, the layers are then shaved and then re-tanned and re-dyed. This is what gives the leather a smooth, supple texture and finally it will be stretched and dried using a special oven moving onto the final stage.
Step Three- The Finishing Process
The final step involves a coating of pigment dye, which will soak deep into the leather, giving the leather its chosen finished colour. After drying, the leather is then coated again with a final fix coat – this protects the finish. It is then dry milled or pummeled, which is a process used to soften the leather, which is then ironed.