Wednesday, August 15, 2012

What is this “Vegetable Tanned Leather” anyway?

Okay, so nobody has asked it quite like that, but I have had that question asked in many ways over the years, so I think it is about time that I answer.

The leather that I use is vegetable tanned, or veg-tan, leather.  The vegetable tanning process I believe is the second most popular tanning process, after chromium tanning (chrome-tanned leather).  The chromium tanned leathers are the ones that most people are familiar with, since they’re used for almost all handbags, belts, upholstery, shoes, and pretty much anything else you can think of.  I say almost all, since there are vegetable tanned leather accessories out there!

The vegetable tanned leather is tanned using tannin and other vegetable-based ingredients (well, tree bark and such).  It stays the natural color of the leather which is a light tan/camel sort of color that can then be painted and dyed to whatever color you’d like.  There is definitely variation from hide to hide in the color and also the properties of the leather – when you go to dye it, each accepts the dye differently.  Chrome-tanned leather, on the other hand, is dyed with chromium sulfate and other chromium salts and is dyed during the tanning process.  The result is a total rainbow of colors.  If you want to see some of the variations, Hide House and Just Leather have an amazing selection.

Below are some photos of a vegetable tanned leather piece in progress.  The first photo shows some of my branding lines and painting.  The second photo is fully painted, and the third shows the piece with the leather dyed in the background. 


Besides the color, one of the main difference in the veg-tan leather vs. the chrome-tan leather is the surface.  The veg-tan leather has a very smooth surface, whereas the chrome-tan has more of a grainy, or fleshy, look to it.  It reminds me almost of goose bumps or follicles. Aside from some scars and other variations, the surface of the vegetable tanned leather is more like a piece of paper than goose bumpy skin.

Vegetable tanned leather also starts out much more rigid than chromium tanned.  It’s got a life, and shape, of it’s own.  This makes it ideal for my purpose, since I can construct something like a leather wine tote that will hold it’s shape without using anything other than leather.  There are different thicknesses (referred to as the “ounces”) that veg-tan leather comes in so I have the flexibility to choose the the leather that will work best for the project given the end weight I want to achieve, and how stiff or flexible it needs to be.

Veg-tan does soften up quickly once you start using it and you get that nice, worn-in, leather look and feel.  Chrome-tan doesn’t seem to change much, other than scuffing and wearing.   I am particularly fond of this picture of two boots (from Blue Owl Workshop), the one in the front using chrome-tan and the one in the back using veg-tan, both with the same color dye, at least in theory:

The one in the back has that old, worn in, vintagey satisfying look to it where it’s not entirely even.  The one in the front just looks like a boot.  With age, that one in the back will just look more and more lovely, too.

The reasons that I choose veg-tan leather, besides the strength and durability, are primarily because I have the freedom to work my paints, carving, dyes, etc., into the surface of the leather and then seal it with a protective coat and actually have them stay, which is something that doesn’t work so well with chrome-tanned leather.  Because the chrome-tan is already finished, it doesn’t accept dye or paint well, it can’t be carved or tooled effectively (though it can be embossed), and I would hate to think of what might happen if I took a branding iron to it!

Because I am doing all the dying and sealing on my leathers, and because I’m using veg-tan, I can create a piece that is colorfast – unlike chromium tanned leather, when dyed properly, veg-tan will not redeposit dye on your clothes or other items.  My personal theory about why purses are lined is to keep the dye on the inside of the chrome-tanned leather from re-depositing on other items in your purse.  Of course, if you carry a vegetable tanned leather purse, you don’t need the lining since it is colorfast.

Something interesting that I found out in writing this blog post is that chrome-tanned leather shouldn’t be used in anything that comes into direct contact with metals – sheaths, pen holders, holsters, etc. – since the residual chromium salts can corrode the metal.  I had no idea – did you?

If you’d like to watch a video of the tanning process, there is one by Hermann Oak Leather Tannery that is interesting.  I do warn you though – watching a tanning video is a little gross, so click and view at your own discretion.

Okay, that’s all for today.  Hope you learned something, and if not, hope you at least enjoyed reading or looking at the photos!



1 comment:

Louie said...

Veg tanning is also an "environmentally friendly" tanning process.