>>> vegetable tanned leather that has gotten really dark and discolored.
These are the contributing factors that gotten the vegetable-tanned leather really dark and discolored.
1- Body oil and grease
Body oil and grease when penetrates the leather it saturate it and darkens (leather stuffing oils and conditioners will also darkens the leather).
2- Sweat
Sweat that ages shift from almost neutral pH to alkaline pH (so does any solution that has a pH value more then 7) will exaggerate the discoloration. When pH value moves higher, the vegetable-tanning agents breaks the hydrogen bonding and migrates with a darkening effect.
>>> Is there a way to restore that?
A- Body oil and grease are removed by emulsification with Degreaser-2.2 > Acidifier-2.0 > Hydrator-3.3 system.
B- The migrating tanning agents darkening effect is rectify by redox (reduction-oxidation) reaction with Vachetta-2.8.
Caution:
Cracks preventing is the utmost concern when comes to cleaning aging vegetable-tanned leathers.
1- The leather must not be put to dry without replenishing the leather with Fatliquor-5.0 sufficiently (average 14% when dry with fat and oil). Fatliquor-5.0 is a ionic negative (-ve) charged oils that hydrogen bond with the leather protein fibers, unlike stuffing oils that clogs up the breathing pores and manifesting as darkening effects.
A holistic approach with supporting system
Leather Doctor Kit-V4 - Vachetta Leather Darkening Removal Kit
is recommended for further readings from:
http://www.leatherdoctor.com/kit-v4-...g-removal-kit/
Roger Koh
Leather, Skin & Hair Care System Formulator
Consultant / Practitioner / Instructor / Coach
web: www.leatherdoctor.com
forum: www.leathercleaningrestorationforum.com
email: [email protected]
