Product Overview
Nubuck is created by buffing the grain side of aniline-dyed leather to produce a fine, velvety nap—often referred to as velvet suede. This absorbent, protein-based material is hydrophilic (water-loving) and oleophilic (oil-loving), making it especially susceptible to body oil, grease, and sweat.
When saturated with sweat, nubuck invites bacterial activity that ferments into ammonia—turning the leather alkaline and destabilizing its structure. This can lead to dye bleeding, tackiness, and weakening of the protein-tanning bond.
Nubuck is an amphoteric material, meaning its pH-sensitive structure can shift from positively to negatively charged, accelerating deterioration when exposed to high alkalinity.
Nubuck Degreaser 2.2
Nubuck Cleaner 4.5
Nubuck Rinse 3.0
Nubuck Acidifier 2.0
Nubuck Hydrator 3.3
Nubuck Fatliquor 5.0
Nubuck Conditioner S
Nubuck Brush 2
Nubuck Eraser 4
Towel 5
With its pH-balanced formula (4.5), it effectively cleans delicate materials without causing common problems like ring marks, browning, or texture damage. Whether you’re cleaning high-end accessories, shoes, or upholstery, this cleaner is an ideal choice for maintaining your items’ integrity and appearance.
This pH 2.0 acidifier helps correct issues like tackiness, dye bleeding, and stiffness by rebalancing the leather’s pH and reinforcing its internal structure.
By strengthening the ionic bond between negatively charged tanning agents, dyestuffs, and fatliquors with the positively charged nubuck protein fibers, this treatment brings leather back to a healthy, squeaky-clean condition.
1️⃣ Hydrator 3.3 Reopens the Collapsed Fibrous structure
- Leather that’s dried out or stiff has a collapsed internal fiber structure.
- Hydrator 3.3 (pH 3.3) is designed to penetrate deeply and relax these stick-together fibrils.
- It displaces impurities (e.g., residual soiling, alkaline cleaners, or sweat contamination) that interfere with leather’s softness and flexibility.
2️⃣ Hydrator 3.3 Restores pH balance for Better Absorption of Fatliquor
- The acidic pH of Hydrator 3.3 helps re-align the ionic charge of the leather’s protein fibers, making them more receptive to fatliquor’s amphoteric chemistry (positive-negative molecular bonding).
- A pH imbalance (e.g., from alkaline exposure) prevents proper bonding of fatliquor, so Hydrator 3.3 prepares the structure for optimal uptake.
3️⃣ Hydrator 3.3 Facilitates Wicking and Removal of Foreign Contamination
When leather is thoroughly hydrated to the point where moisture oozes out when gently pressed between fingers, Hydrator 3.3 promotes the wicking action that draws out solubilized foreign contamination and residues toward the surface. These impurities can then be:
- Blotted away while wet, and
- Erased when dry (especially for nubuck and suede) to restore an even appearance.
Without this critical hydration step, embedded contaminants remain trapped within the fiber structure, hindering the uniform distribution of fatliquor and compromising the leather’s suppleness and aesthetic restoration.
- Dry Soil Removal: Use Brush 2 to remove dry soil and loose debris.
- Surface Erasing: Rub Eraser 4 over heavily used or greasy areas to lift embedded grime and deteriorated nap.
- Vacuum: Thoroughly vacuum eraser crumbs and remaining dry particles.
The Wet-Process in the Leather Doctor® system is a scientifically sequenced method rooted in tannery principles to restore Nubuck leather’s structure, cleanliness, pH balance, and suppleness. Nubuck, being an amphoteric, pH-sensitive unfinished leather, requires strict pH control and continuous moisture to prevent damage and support effective degreasing restoration.
Nubuck must remain continuously damp to:
- Maintain fiber softness and prevent shrinkage or distortion.
- Allow chemical migration (wicking of soiling and redistribution of dyestuff).
- Ensure effective bonding of fatliquors during absorption.
- Prevent the leather fibers from locking up in a collapsed state as they dry.
- Avoid surface streaking or blotchiness caused by uneven drying or residual residue.
Tannery Principle: Leather Doctor system mimics wet-end tannery processes, where rehydration, pH balancing, and fatliquoring occur in a single, uninterrupted wet cycle—drying between steps breaks the chemistry chain and causes irreversible fiber collapse or uneven appearances.
Summary: Why Nubuck Must Stay Damp
Step Why Keep Damp? Degreaser 2.2 → Cleaner 4.5 Allows emulsification and removal of grime without locking in residue. Cleaner 4.5 → Rinse 3.0 → Acidifier 2.0 Maintains chemical continuity for pH stabilization. Acidifier 2.0 → Hydrator 3.3 Prevents fibril collapse and promotes wicking + dye redistribution. Hydrator 3.3 → Fatliquor 5.0 Enables deep fatliquor penetration and ionic bonding.
- A low-pH, solvent-free degreasing agent that breaks down embedded oils and sweat contaminants.
- Applied with agitation and allowed to dwell while still damp.
- Purpose: Dissolves body oil, grease, and sweat with Leather-Safe™, pH 2.2 formulation.
- Shake well to form a gel.
- Saturate the stain using Brush 2 or Eraser 4.
- Extract with Towel 5—repeat until the towel shows clean.
- For stubborn stains, dwell 5–60 minutes (prevent drying), then repeat extraction.
- A leather-safe pH 4.5 cleaner that emulsifies and lifts remaining soiling without disrupting the protein-fiber structure.
- Must be worked in while the surface remains damp from Degreaser 2.2 to ensure continuity.
- Purpose: Gently removes general soiling from Nubuck (pH 4.5).
- Dilution: 1 part cleaner to 64 parts distilled water.
- Shake and spray evenly.
- Gently agitate with Brush 2 or Eraser 4.
- Let dwell 3–30 minutes (don’t allow to dry).
- Blot and extract with Towel 5.
- Follow immediately with Rinse 3.0.
- Rinses away cleaner and soiling residues while lowering the pH to a mildly acidic level.
- Helps stabilize the leather's pH closer to its isoelectric point (3.0–5.0), preparing it for effective bonding with the next acidic phase.
- Purpose: Removes residue and balances pH to prevent tackiness and dye migration.
- Dilution: 1 part Rinse 3.0 to 40 parts distilled water.
- Spray evenly and agitate gently with Brush 2.
- Blot and extract with Towel 5 using a blot-and-wipe motion.
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An acidifier that:
- Corrects over-alkalized areas.
- Reinforces the leather’s natural ionic polarity (cationic).
- Prepares the leather structure for optimum absorption of fatliquor (anionic).
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Leather must remain damp to allow ionic exchange during the next phases.
- Purpose: Re-acidifies Nubuck to strengthen internal fiber bonding and neutralize alkaline damage.
- Dilution: 1 part Acidifier 2.0 to 25 parts distilled water.
- Apply evenly using Brush 2 or sponge.
- Gently agitate and blot with Towel 5 until the leather feels squeaky clean.
- Repeat if needed.
- Optionally follow with Hydrator 3.3 to flush residual impurities.
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A fiber-relaxing, hydrating agent that:
- Redistributes any residual soiling through wicking.
- Reopens collapsed fiber spaces.
- Evens out surface tension and activates dormant dyestuff.
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Acts as a bridging medium for deep, uniform fatliquor penetration.
- Purpose: Relaxes and plumps leather fibers, reduces stiffness, structural colloidal water movement and preps for fatliquoring.
- Dilution: 1 part Hydrator 3.3 to 25 parts distilled water.
- Apply evenly. Massage in with Brush 2.
- Dwell until fully hydrated—avoid drying out.
- Manipulate surface to release creases.
- Follow with Fatliquor 5.0 before complete drying.
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A tannery-grade fatliquor composed of fat and oil microemulsions that restore:
- Softness, flexibility, and strength by coating individual collagen fibrils.
- Breathability without clogging the nap surface.
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Must be applied while the leather is still damp from Hydrator 3.3 so it can migrate into the open fiber matrix.
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Fatliquor is anionic, and it binds only when the leather’s structure is cationic and moist (from the acidifier and hydrator steps).
- Purpose: Reintroduces essential fats and oils to restore softness, flexibility, and strength.
- Dilution: 1 part Fatliquor 5.0 to 5 parts warm distilled water.
- Apply generously and redistribute with Brush 2.
- Reapply when water evaporates—repeat until saturation is complete.
- Let dry naturally.
- Once dry:
- Erase surface soiling to reveal an even appearance (otherwise repeat).
- Flex or massage to enhance softness (use Hydrator 3.3 as needed during this process).
Final Conditioning – Nubuck Conditioner S
- Purpose: Protects against sticky soiling and enhances nap without forming a film.
- Dilution: 1 part Conditioner S to 19 parts distilled water.
- Shake and mist spray evenly.
- Immediately spread with a lint-free towel or sponge.
- Allow to dry completely.
- Restore nap with Brush 2 for the signature finger-writing effect.
- How to Identify Nubuck Stains?
- How to Use Nubuck Leather Problem Matrix?
- Technical Help and Support?
Stain identification is crucial for effective treatment and is based on six key factors:
Appearance, Odor, Color, Feel-of-Hand, Location, and Buildup or Absorption.
- Observing how the stain looks can indicate whether it is a spill, rub-on, penetration, or surface deposit.
- Some stains may cause dye or finish damage, revealing changes in the leather’s color or texture.
- Smelling the stain can help identify its source.
- Common odors include:
- Moldy (fungal growth)
- Smoke (fire or cigarette exposure)
- Putrid (decaying organic matter)
- Ammonia (urine contamination)
- Color provides a clue to the staining substance but can change over time due to oxidation.
- The leather’s natural color may also influence how the stain appears.
- Red stains: Could be from wine, blood, lipstick, nail polish, or beverages.
- Blood stains: Can oxidize and shift from red to tan, then to black.
- Touching the stain helps determine its type:
- Sticky: Likely from candy, beverages, or sugary substances.
- Brittle and stiff: Could be nail polish, paint, or shellac.
- Greasy smear: Often caused by lipstick, oils, or butter.
- The stain’s location on the leather provides hints about its origin.
- Headrests & armrests: Usually stained by body oil, sweat, and grease.
- Seat cushions: Often show food or beverage spills.
- Stains can be surface-level (built-up) or deeply absorbed into the leather.
- Built-up stains (common on pigmented leather) include paint, food residue, and ink.
- Absorbed stains (common on nubuck, aniline, and unfinished leather) include wine, tea, and coffee.
- Combination stains: Some stains contain both absorbed and surface elements, such as lipstick, ink, and mustard.
- Protein-based stains: Examples include blood, dairy, and egg-based spills.
- Oil-based stains: Often come from grease, butter, and lotions.
- Colloidal stains: May require specialized treatments.
- Sweat stains can chemically alter leather, causing tackiness (when dry) or sliminess (when wet).
- Dye stains may show up when wiping with a white towel—this indicates color crocking.
- Fatliquor leaching (spew) appears as a milky film and causes leather to become stiff and prone to cracking.
Nubuck Leather Problem Solving Matrix
- Hydrator 3.3,
- Fatliquor 5.0, and
- Conditioner S.
Updated: January 3, 2025 | April 9, 2025 | June 25, 2025 by Roger Koh.