Vegetable-Tanned (Finished or Topcoated) - B & B Italia - leather chair

These leathers are identified as vegetable-tanned leathers and have the tendency to brown due to the difference pH value between the water source and pH neutral of the leather or iso-electric point also known as the pI. Generally water has an average pH value of 7 and vegetable-tanned leather is more pH sensitive with an average pH value of less than 4. This pH difference makes the tanning agents and the fatliquor leaches out. Besides browning discoloration the leather most times will feel stiffer when the leather structure fibers begins to becomes stick together.

The browning concentrates on the more absorbent details which may indicates that this leather probably have a clear topcoat like AnilineTop-21Gloss or satin. We also see a sort of watermark effect in letters.

Here are the testing for both the damaged topcoat that results in the unwanted browning staining effect

1st – Browning Treatment
Vachetta-2.8 is used for testing the removal of the brown stains by using a cotton swab and applying to a localized line of stains to see the effect of the result. Vachetta-2.8 works by redox chemical action and the result only manifest after it dries. Dried residue is erased with Eraser-4 and it should reveal a lighter effect ready for topcoat testing.

2nd – AnilineTop-21 Gloss or Satin is applied to the above and dry between coats to evaluate the finish match.

It would looks like Vachetta-2.8 as an add-on to the Kit-A6.tc would give you a complete control over the testing and eventual restoring the leather to its preexisting condition.

I will explain the actual procedure after the above test for a holistic restoration both for appearance and for pH chemistry integrity.

Roger Koh
Leather Care Consultant
[email protected]

Further readings:

Vegetable-tanned leather is tanned using tannin and other ingredients found in vegetable matter, such as tree bark prepared in bark mills, and other similar sources. It is supple and brown in color, with the exact shade depending on the mix of chemicals and the color of the skin. It is the only form of leather suitable for use in leather carving or stamping. Vegetable-tanned leather is not stable in water; it tends to discolor, so if left to soak and then dry it will shrink and become less supple, and harder. In hot water, it will shrink drastically and partly gelatinize, becoming rigid and eventually brittle.

Attachment 4255
Leather Doctor® Kit A6.tc, aniline leather topcoat refinishing kit is designed for topcoat repairs from friction wear, accidental scratch, scuff and abrasion to deteriorating greasy sweat stains. These topcoat damages are identified as white, dull or darkening stain from bare body contacts. Accidental whitish damages in most cases are free of soiling and direct AnilineTop-21G application with in between dry sanding rectifies most damages. Repairs to topcoat from daily wears that dulls will require a degreasing to remove penetrated rub-in soiling prior to topcoat application in a sequence process including Degreaser-2.2 follows with Rinse-3.0; Hydrator-3.3 follows with Fatliquor-5.0 prior to topcoat application. In a greasy and sweaty topcoat damaged areas especially to the headrest and armrest, a deep degreasing is essential follows with Acidifier-2.0 to stabilize the hydrogen bonding between the protein fibers with the other leather constituent like the tanning agent, dyestuff and fatliquor. This deep degreasing process is assisted by leather Eraser-4 in both the wet and dry cleaning process to remove soiling particulates off the leather surface. Hydrator-3.3 helps in the colloidal water movement bringing suspended soiling particulates to resurface through a dwelling and wicking process. Fat and oil is replenished by Fatliquor-5.0 in an emulsion form to penetrate into the leather structure. Once the fat and oil is hydrogen bond with the protein fiber, the water content breaks free leaving a breathing space for natural transpiration. The fat plumps the leather with fullness preventing the leather structure from collapsing during compressing and flexing while the oil lubricates the fiber from sliding smoothly over one another like millions of connecting hinges. Protector-B+ impart a non-stick, rub-resistant surface with a buttery feel helps reduce friction wear to the topcoat and extended a high level of appearance for a longer period of time. When the leather is contaminated with foreign soiling, it is essential to look at topcoat refinishing in a holistic approach. Note that the cleaning and rejuvenating products suffix denotes its pH value in this leather-safe aniline leathers topcoat refinishing system.

Attachment 4256
Leather Doctor® Kit V3, unfinished leather care system is design for corrective appearance of vachetta, saddlery and veg-tan leathers from browning liquid stains. These alkaline pH sensitive leathers when neglected often suffer unsightly browning stain marks from a variety of liquid sources. Even apparent clean rain and tap water often leave a lightening spot with an outer ring. The pH 7 alone of water will often cause a rippling effect on the tannin that destabilize and causes it to moves. Browning correction is perform by using Vachetta-2.8, a pH 2.8 specialty leather cleaner that is particularly effective in emulsifying oily soiling, lightening suntan and water staining effect. A holistic system includes rejuvenating the leather structure for softness with Hydrator-3.3 to relax, follows with Fatliquor-5.0 to soften when dry and protecting with the healing properties of Protector-D thereafter. The lightening effect takes place when the leather dries. When leather is wet and dry again, it will often stiff up, as the fibers becomes stick closer together. Hydrator-3.3 helps separate and open up the inter-fibrillary spaces preconditioning for effective Fatliquor-5.0 replenishing to lubricate for leather flexing smoothness from cracking. Replenishing the leather structure with fat and oil after browning corrective cleaning besides the softening effect also prevents the ingress of liquid stains as a preventive measure. When leather is full of fat and oil, it makes the leather less absorbent. Fat and oil conditioning or rejuvenating with Fatliquor-5.0 mellows and enrich the appearance of the leather while most oil conditioners will simply darkens and dulls the appearance poorly. Protector-D enhances a rub resistant draggy-feel against friction rubs and is use routinely to conceal and fill scuffmarks. Body contact areas should be clean routinely with Clean-3.8 follows with Rinse-3.0, thereafter applied with non-stick protection and commence for another cycle of use. Darken and prolong body grease and sweat contacts will require a degreasing process with Degreaser-2.2 follows with Acidifier-2.0 in most cases. Preventive cleaning and protection to shield against sticky soiling, with the abilities to heal and conceal lightening scuff and abrasion marks keeps the leather appearance level high at all times rather than relying on corrective or salvage cleaning where the cleaning appearance deteriorates and diminishes with each cycle. Note that the mentioned products suffix numbers denotes its pH value in this holistic approach to removing vegetable, plant and water stains from vachetta, saddlery and veg-tan leathers.

Vegetable-Tanned (Finished or Topcoated) - B & B Italia - leather chair – water stains