VEGETABLE TANNING (AND WET WHITE)
Vegetable tanning is a tanning method that uses natural ingredients such as the bark of chestnut trees to tan the leather. Plant extracts are used for the purpose of tanning in this process. This means the finished product colour is usually warm, rich tones of natural browns. Vegetable tanning is usually done by tanneries that have a rich heritage of tanning hides. Unlike chrome tanning, vegetable tanning can take up to 40 days to produce a piece of dyed leather.
Wet white tanning refers to organic tanning methods. The biosynthetic is used to tan the leather, which result in a semi-finished leather that looks white-tinted.
This fairly new method of tanning has been gaining popularity, partially due to increased concern for water treatment systems and the environment.
The off-cuts from wet white tanned leather in the form of shavings can be recycled or used as fertilizer, in contrast to wet blue tanning methods.
Advantages and Disadvantages of Vegetable tanning
- Only natural ingredients (no harmful chemicals) are used when dying the hides
- Lighter in color and can be converted into pastel Shade leathers
- High softness
- Good lightness
- Natural sensation
- Pleasant touch
- Beauty over the time
- Environmentally friendly and can be recycled.
- Each leather product that is dyed using vegetable tanning is completely unique.
- Rich, warm-tone colors which look completely natural.
- High performance leather can be obtained, often better than chrome tanning
- The process of vegetable tanning takes a long time, and can take up to 60 days.
- Vegetable tanning doesn’t react well with water and can stain easily.
- Products that have been vegetable tanned are more expensive.
- The colors you can produce from vegetable tanning are limited.
- Direct heat can cause vegetable tanned products to shrink or crack.
CHROME TANNING (AND WET BLUE)
80-90% of leathers in the world are tanned by chrome (also known as mineral) tanning. Chrome tanning uses a solution of chemicals, acids and salts (including chromium sulphate) to dye the hide. It’s a very quick process, taking about a day to produce a piece of tanned leather. First the hide is ‘pickled’ by being left in the acid salt mixture, before being placed into the chromium sulphate. All hides then come out looking light blue (known as ‘wet blue’) and then have a finishing colour applied.
Wet Blue is the tanning process where chromes are used to process the leather from raw hide to finished leathers. This process causes the semi-finished leather to look blue-tinted.
Advantages and Disadvantages of Chrome tanning
- Quick and easy to produce, usually only taking up to a day.
- Stain resistant and water can roll off the surface easily.
- Soft and supple to the touch.
- Colour remains the same throughout the products life.
- It’s cheaper to buy than vegetable tanned leather, which means it is also easier to find.
- It has a high degree of thermal resistance.
- Chrome tanning is very bad for the environment.
- It’s produced with little skill and very often mass produced.
- It doesn’t wear very well or last long and can crack after a few months of use.
- Chrome tanning often smells of chemicals.
- It doesn’t appear (neither is it) very natural.
HOW TO TELL THE DIFFERENCE
Do you want to buy a vegetable or chrome tanned leather product but aren’t sure how to tell the difference? Or do you have a ladies leather handbag and want to know how it’s been tanned? There are a couple of things you can do to test the type of leather it is.
- Firstly; if you are shopping for a leather product you can smell the product. If the product smells chemically then it’s probably been chrome tanned. Vegetable tanned leather smells sweeter and not at all like chemicals.
- Secondly; you can scratch the leather product (but do not do this in shops!), if the scratches can be easily buffed out with minimum effort then it is probably vegetable tanned leather.
- Thirdly; the burn test! You can burn the leather product to find out what type of leather it is. Simply hold a lighter up against the product; if it has no effect on the leather then it is vegetable tanned! If it produces any ash at all it will be grey, chrome tanned will be a distinctive green. Note: never do this in a shop or with a much loved piece! Only do this test if you know of the quality leather or you do not care that much about the product you are testing.