Aniline (Sauvage) - Identification and restoration advice needed chesterfield leather chair

>>> how to restore this chair to its former color if possible,

This leather finishes type is identified as Aniline with a gloss finish and the Aniline (A) Leather Problem Solving Guide will be used as reference for the sequence of process (see guide below).

>>> . . . restore this chair. . .

There are a few aspect of restoration to the chair for consideration:

1st - The leather structure pH chemistry integrity.
Where the ionic hydrogen bonding between the protein fiber and its other leather constituents like the tanning agents, fatliquor and dyestuff has to be strengthen. Leather is pH sensitive, its protein fiber composition is an “amphoteric” material with an ionic positive (+ve) charge, while the three basic leather constituents (tanning agent, fatliquor and dyestuff) are non-amphoteric with an ionic negative (-ve) charge. The protein leather fiber is vulnerable to alkaline over exposure especially with any solution of pH value higher than 7. pH value above the leather neutral or iso-electric point also know as the pI of leather averages 4, will cause the protein fiber to shift ionic negative (-ve), thus initiating the process of leather denaturing or reverting to rawhide as the ionic attraction between the protein fiber and its other constituents weakens and repels just like magnets “like poles repels”. The dissociating weakening ionic attractions sets in manifesting as tackiness from the tanning agents, dryness from the fatliquor and dye migration from the dyestuff. Returning the pH chemistry integrity of the leather with a healthy squeaky feel is an important consideration not to be neglected.

2nd
Stain Removal – Degreasing:
Body oil, grease and sweat not only accumulate on the leather grain surface but also penetrate in heavier soiling areas like the armrest and headrest staining it clearly visible. Degreasing from the surface film is easier but beneath the surface becomes a challenge with greater volume that will require multiple wicking up cycle to resurface until the leather structure is exhausted free from soiling contamination. This degreasing process is accomplished with Degreaser-2.2 > Acidifier-2.0 with build-in protonating the protein fiber ionic positive (+ve) at the same time in a 2-in-1 process, thus accomplished restoring the pH chemistry integrity simultaneously.

3rd
Stain Removal – Protein Stain:
Protein stain like body fluid and foodstuff has the tendency to coagulates or binds with the protein leather fiber making removal much more tedious and will require a high pH value leather protein specialty cleaner like d’Protein-10 > Acidifier-2.0 system for effective removal. A high pH swells for easier deflocculating the stain and stubborn deposits has to be work out with a dental prick, spatula, bamboo skewers or toothpick to complete clear them off the surface.

4th
Stain Removal – Browning Stains:
The possible cause of browning may comes from various source, iron from blood will require a d’Tarnish-1.3 treatment and any metallic staining will require this treatment as well. Another source of browning stains come from vegetable and plants tannin like age and old beverage spills, wine, coffee, tea and any stains from vegetable and plants derived will require this treatment with d’Tannin-3.5.

(Refer to the Aniline (A) Leather Problem Solving Guide for other stain type removal).

5th
Restoring the Original Fatliquor (fat, oil and water):
The softness and strength of leather much depends on the fatliquor and up to 14% by weight is the average standard tannery specification for leather suppleness. Fatliquor being an volatile organic compound either diminishes by transforming into gas and evaporates or being leach away by alkaline solution during cleaning, thus leather will always becomes stiffer after drying to a degree. Staking or massaging with an empty leather will weaken or cracks it – thus soft and weak. On the contrary staking or massaging with a well-replenished leather will soften and strength it – soft and strong. This process is accomplished with Hydrator-3.3 > Fatliquor-5.0 system.

6th
Restore the Surface Grain:
When surface grain feels rough to the feel of hand in most cases the topcoat has been worn away or crack. In severe cases the leather grain cracks as well and extreme cases the leather is over-stretch and weak. Restoring the deteriorating topcoat is done with them stripping of physically with Razor-60 or chemically with Stripper-2.3 prior to refinishing new AnilineTop-21G or heavy-duty 76G. Surface skin damages are restored by Adhesor-73 to return skin smoothness. Structure weakness restoration is restored by Impregnator-26 into the leather structure for tightness and strength.

>>> A color restore is however desired to its former color if possible. . .

When restoring to its former color, the remaining existing stain need to take into consideration. The remaining darkest stain if any becomes the lightest color practical, otherwise the existing stain shows through and in most situation the end result of the desired color becomes limited to a range of dark brown just to camouflage the stain.
Dyestuff for such application for surface dyeing control would be using the surface coating transparent dyestuff - Aniline-76 > AnilineTop-76 (gloss to matte luster) system.

>>> if not I would like to just preserve it. . .

Preserving it would be the easier route to take, leaving the color for the last resort if preserving it proves wanting.
Through the processes the color intensity may bounce back especially with intense hydrating with Hydrator-3.3, surface skin repairs with Adhesor-73 and AnilineTop-21 or 76 refinishing may bring back close to original appearance.

Tips:
Working with transparent aniline dyestuff is “not what you see is what you get”, unlike working with opaque pigment color that produces even color. The picture in post #2 shows inconsistent appearance when the leather was first dyed. The second attempt will be more of a challenge to deal with more surface damages that will show through as blemishes instead of grain beauty thus a dark brown would be the only practical color to consider.

Other issue to consider when comes to redyeing we will discuss later.

Aniline (A) Leather Problem Solving Guide
Attachment 2162

Product information (see more from this link: http://www.leatherdoctor.com/servlet...ers/Categories) Products mentioned may be add-on to this Kit A6.tc to test it out.

Attachment 2161
Leather Doctor Kit A6.tc – Aniline Leather Topcoat Refinishing Kit
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.

Roger Koh
Leather Care Consultant
www.LeatherDoctor.com