Leather Identification - darken and harden worn areas

>>> I do not know what type of leather this is and there are no tags.

By appearance from pictures, this is the typical Aniline (Sauvage) finish type.

Here is a general description of this leather finish type:

Aniline leather is soft and natural. They are usually first treated with transparent dyestuff to make the grain and natural characteristics more visible. Modern tannery dyeing is done in a rotating drum in a continuous process follows with fatliquoring. When dried thereafter, the leather goes through another selection or grading to decide the best treatment to bring out their potential softness and natural look. Thus, further sub-divide into various varieties. However, the bulk of aniline leathers after dyeing may reveal uneven grain dye absorbency and too many faults, so that the variation in color over the entire grain surface is too great for many leather fabrications.

Varieties of aniline leathers may be referred to as “full sauvage aniline” with differing intensity of dye absorbency appearance.

>>> My main areas of concern are the dark hard worn areas and some stains here and there.

The stains are first removed prior to rejuvenate the leather for suppleness. Color intensity may be activated during the rejuvenating process and the next step is to refinish its worn topcoat follows with a rub-resistant protection.

On location where there is constant and typical body contact the darken areas are mainly from our body oil, grease and sweat and this is removed with Degreaser-2.2 > Acidifier-2.0 > Hydrator-3.3 system process.

Use this guide for proper other stain identification:

Leather Stain Identification:

Appearance
- Stain identification by appearance will show whether it the characteristic of a spill, rub-on, penetrated or deposited. It may also reveal dye or finishes damages cause by the stain.

Odor
- Stain identification by smell can be very helpful in positive identification. Some of the more common odor may be moldy, smoke, putrid or ammonic from urine.

Color
- Stain identification by color will also give a clue to the staining material. If the stain is red, it could be beverages, nail polish, lipstick, blood, or some other things. Color identification may not necessary be right; with time, a red bloodstain may turn to a stain that is tan to black. The color of the leather may mesmerize or alter the color of the stain.

Feel of Hand
- Stain identification by feel of hand may help determine the stain types. For instance, if it is sticky and red it could be candy, beverages or other things that have sugar in them. If the stain is brittle and stiff, it may be nail polish, shellac or paint. If it smears, it may have grease base to it, such as lipstick.

Location
- Stain identification by location may give a clue as to the makeup of the staining substance. If it is dark at the headrest or the edge of the armrest, it is most likely stain by body oil, grease and perspiration by hand or by head.

Buildup or Absorbed
- A stain may take several appearances. The stain may be lying on top of the leather (buildup) on most pigmented leather or absorbed into the leather on most unfinished, aniline and nubuck leathers. Naturally, it could also be a combination of absorbed and built up. If it has been absorbed, this will be an indication that it was a liquid when it penetrates the leather. It should also alert us that it might have chemically changed the dye of the leather. An example of this would be a perspiration stain that has reacted with the leather dye and changed it in some way. This would occur more likely on dyed absorbent leathers. The perspiration could also have weakened the fibers of the leather. In any event, this leather may show a marked color change in that area after spotting, and possibly after cleaning. Examples of built up stains are paint and some foodstuff, etc. Examples of absorbed stains are beverages, wine, tea, coffee, etc. A combination stain may be lipstick, ink, mustard, etc. it will have part of its staining matter absorbed into the leather and part of it accumulated on the surface. A stain may also be a substance that has wet solvent-soluble and dry solvent-soluble components combined. An example of this would be gravy, which contains grease, flour (from plant), and milk (from an animal). Paint type stains are readily detected because of their stiff nature and generally bright colors and they seem to be sitting on top of the leather. When identifying stains always try to determine whether they are of a protein, cellulose, oil based, or a colloidal make-up nature. Three common types of soiling or stain are solvent-soluble, water-soluble and insoluble. Stains are frequently of a combination nature, and in most instances, there will be no information from the customer regarding the stain especially if they are bought used.

Identify the leather problem from the left column with the top row product recommended and the numbers denotes the sequence of steps. When leather have compound issue combine the soiling, stain and odor types as the cleaning phase-1 and the leather rejuvenating with Hydrator-3.3 > Fatliquor-5.0 as the second phase-2. Structural problem as third phase-3, Finishing as phase-4 and protection of the finishes as phase-5.

Attachment 6582
Here is the typical topcoat refinishing system after body oil, grease and sweat removal, other stains have to be removed accordingly prior to leather rejuvenating it at phase-2 and so on.

Attachment 6583
http://www.leatherdoctor.com/kit-a6-...finishing-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 System Formulator
Consultant / Practitioner / Instructor
web: www.leatherdoctor.com
forum: www.leathercleaningrestorationforum.com
email: [email protected]