The system works by stripping, degreasing, cleaning, rinsing, hydrating, softening, priming, dyeing, topcoating, and conditioning leather surfaces.
Why is there a need to re-dye?
Aniline leather, by its nature, is dyed through and through without an opaque surface coating, making its color vulnerable to:
UV fading from sunlight exposure.
Abrasion wear from regular use.
Staining or uneven discoloration from body oils, grease, and sweat.
Previous improper cleaning that may strip dyestuff from the surface.
Re-dyeing restores:
The depth and richness of color that has faded or worn.
The evenness of appearance, masking blemishes and stains.
The natural aniline character, allowing light to penetrate and reflect through the dye, preserving that signature transparent look unique to aniline leather.
Why is the leather structure's integrity not seen as important as appearance?
It’s a common misconception in the leather care industry to prioritize appearance over structure.
Many refinishing processes focus on cosmetic results—making the leather look new—while overlooking:
Internal fatliquor content that determines softness, strength, and flexibility.
pH balance crucial for preventing deterioration (such as cracking or stiffness).
Ionic bonding integrity between leather fibers and their tannins/fatliquor.
Leather Doctor’s position:
While appearance matters (hence the re-dyeing and gloss topcoat), the integrity of the leather’s structure is fundamental to long-term performance and preservation.
This is why the Leather Doctor system emphasizes hydrating and fatliquoring alongside refinishing—restoring what the leather needs internally before beautifying it externally.
Why is a holistic scientific approach emphasized in the Leather Doctor system based on tannery science?
Leather Doctor’s system is built on tannery science principles that recognize leather as a living material, even after processing.
The key reasons for a holistic, scientific approach are:
Leather is amphoteric (pH sensitive) — if its pH balance is disturbed (e.g. by sweat, alkaline cleaners), it weakens structurally.
Fatliquor loss leads to stiffness, cracking, and weakness — merely covering damage with dye ignores the root cause of deterioration.
True restoration begins at the fiber level — replenishing the original fat, oil, and moisture content as done in the tannery.
Scientific sequencing ensures compatibility and long-term results — each product prepares the leather for the next step (e.g. cleaning neutralizes pH and residue before softening and refinishing).
This tannery-aligned system ensures leather is not just cosmetically improved, but structurally rejuvenated, preserved, and protected for the future.
Summary of the 4-Sequence Refinishing Process
Cleaning System (5 products)
Stripper 2.3 – Removes deteriorated finishes.
Degreaser 2.2 – Eliminates body oil, grease, sweat.
Soft 3.8 – Deep cleans remaining soiling.
Rinse 3.0 – Rinses off degreasing and cleaning residues.
Acidifier 2.0 – Balances pH, stabilizes structure.
Softening System (2 products)
Hydrator 3.3 – Rehydrates and relaxes leather fibers.
Fatliquor 5.0 – Restores fats and oils for suppleness and tensile strength.
Refinishing System (4 products)
Aniline 21 – Reactivates and enriches natural color.
Adhesor 73 – Primes for adhesion.
Aniline 76 – Applies fresh dye for uniform coverage.
Gloss 76 – Seals with a durable, vibrant gloss topcoat.
Conditioning System (1 product)
Protector B – Imparts a buttery feel, resists soiling, reduces friction wear.
Key Takeaway
Unlike superficial refinishing approaches, Leather Doctor’s system respects leather’s biochemistry, providing true restoration from within, not just surface beautification.
The goal: keep leather both beautiful and structurally sound, as it was meant to be.
Kit A7.cl concentrates contents require 1581g (1.8 quarts) distilled water to be mixed and filled before use with these selected leather-safe products:
Kit A7.cl Product Summary Includes:
Leather Deglazer Stripper 2.3 by Leather Doctor® is a Leather Finish Remover and Surface Prep pH 2.3 balanced solution formulated to safely strip unwanted finishes, aged conditioners, oil and grease contamination, waxes, inks, and paints from leather surfaces.
Stripper 2.3 prepares the leather for new refinishing or recoloring by restoring its pH balance, ensuring the leather remains supple and receptive to new coatings.
Leather Degreaser 2.2 by Leather Doctor® is a professional-grade, water-based solution formulated to remove body oils, grease, and sweat from leather surfaces.
Deep-Cleansing, Leather-Safe Degreaser for All Leather Types:
Degreaser 2.2 Key Benefits:
Ideal for use on headrests, armrests, collars, cuffs, handles, and steering wheels, this powerful cleaner penetrates deep to lift embedded grime while maintaining the integrity of the leather.
With a pH value of 2.2, Degreaser 2.2 is leather-safe and prevents common issues like dye bleeding and surface damage. Unlike harsh solvent-based alternatives, it cleans effectively without drying out or weakening the leather structure.
Suitable for all leather types—including absorbent and sensitive finishes like Nubuck and suede—Degreaser 2.2 is an essential tool for restoring and preserving leather’s natural beauty, softness, and longevity.
Leather Soft Cleaner 3.8 by Leather Doctor® is a leather-safe, pH 3.8 mild cleaner formulated to effectively emulsify and lift general soiling without causing common side effects.
Soft 3.8 is among the mildest of cleaners with a lower cleaning power than Strong 4.3 and Super 4.9.
Why Choose Soft 3.8?
Soft 3.8 is the mildest among the Leather Doctor's range of cleaners which is safe for all leather, nubuck, and suede.
Always test clean with Soft 3.8 and evaluate the result to your satisfaction before progressively increasing the cleaning power to Strong 4.3 or Super 4.9.
Accumulated soiling may require the next level of Prep 4.4 or Prep 7.7 preparatory cleaners.
Penetrated body oil, grease, and sweat requires Degreaser 2.2 and is rinsed with Acidifier 2.0.
Provides the “just right” strength—a balance between under-cleaning and over-cleaning.
Part of a holistic leather-safe system: always follow rinse with Rinse 3.0
Soft 3.8 Key Benefits:
Gently Cleans Without Harsh Effects – Maintains leather’s natural integrity
Works Seamlessly with Prep 4.4 and Prep 7.7 – Allows for after cleaning of sticky residue
Prevents Rings & Browning – Ideal for pH-sensitive leathers
Residue-Free with Rinse 3.0 – Restores leather’s pH balance for long-term care
Leather Rinse 3.0 by Leather Doctor is a pH 3.0 leather-safe rinse formulated to remove suspended soil and restore the pH balance of leather, ensuring its structural integrity and long-term durability.
Rinse 3.0 Key Features & Benefits:
Removes Suspended Soil – Lifts and extracts emulsified soiling for a clean, residue-free finish.
Neutralizes Alkaline Residue – Restores pH balance to prevent damage from alkaline overexposure.
Prevents Tackiness & Dye Bleeding – Stabilizes the leather structure, reducing unwanted texture changes.
Enhances Leather’s Ionic Charge – Recharges the leather with a positive (+ve) charge, improving its ability to bond with negatively (-ve) charged tanning agents, dyestuff, and fatliquor.
Preserves Suppleness & Durability – Helps maintain the leather’s softness, preventing stiffness and cracking.
Leather Acidifier 2.0 by Leather Doctor® is a pH 2.0 acidic rinse designed to control, neutralize, and restore leather’s natural pH balance.
Acidifier 2.0 prevents leather from denaturing, which can lead to bleeding, streaking, tackiness, and structural weakness due to alkaline overexposure.
Acidifier 2.0 Key Benefits:
Neutralizes alkaline contamination from cleaners, sweat, and body oils
Prevents dye bleeding and color streaking
Reduces leather tackiness and improves texture
Strengthens leather fibers and enhances structural integrity
Leather Hydrator 3.3 is a leather-safe pH 3.3 aqueous solution formulated by Leather Doctor® to hydrate, relax, and restore the leather’s internal structure during cleaning, conditioning, and restoration processes - in line with its tannery science-based function:
It mimics the hydration stage of tannery pre-conditioning to prepare leather for deeper structural rejuvenation.
Hydrator 3.3 Key Benefits:
Rehydrates dried, stiff, or collapsed fiber structure
Restores moisture to the leather’s protein fibers, relaxing them so they can regain flexibility.
Essential before fatliquoring (with Leather Fatliquor 5.0) so fats and oils can penetrate deeply and bond properly.
Displaces and flushes out impuritie
Helps suspend and wick out residual body oils, sweat, soiling, or alkaline contamination that may have penetrated the leather.
Balances pH and readies leather for further treatments
The mild acidic pH of 3.3 re-aligns the ionic charges of the leather structure, making it receptive to fatliquor and protecting against pH damage.
Helps reduce stiffness and restore suppleness
When used alone or in conjunction with fatliquor, Hydrator 3.3 is critical for achieving uniform softness, without patchiness.
Tannery science basis
In professional tanning and retanning, hides are hydrated before fatliquoring or coloring to ensure that treatments penetrate evenly and bond effectively.
Leather Hydrator 3.3 replicates this essential tannery hydration step at the restoration stage, particularly for dried-out, stiff, or aged leather.
Leather Fatliquor 5.0 by Leather Doctor® is a leather-safe pH 5.0 emulsion of fat, oil, and water designed to replenish the original fatliquor content of leather’s fibrous structure.
It restores leather’s internal lubrication, flexibility, strength, and resilience—mimicking the essential fatliquoring stage in professional tanning and retanning processes.
Fatliquor 5.0 Key Benefits:
Lubricates and nourishes the leather structure
Fatliquor 5.0 deposits fat and oil molecules that bond to the amphoteric protein fibers.
These lubricate the fibrils, allowing them to slide over each other without stiffness, brittleness, or cracking.
Reinforces tensile strength and elasticity
Proper fatliquoring prevents fiber embrittlement and maintains leather’s natural strength and softness.
Restores suppleness and prevents future damage
Leather loses fatliquor over time due to aging, heat, sunlight, alkaline exposure, or cleaning.
Replenishing it prevents shrinkage, stiffness, and cracks.
Provides long-term structural protection
Maintains leather’s dimensional stability and ability to flex without damage.
Tannery science basis:
In the tannery, fatliquoring is one of the final and most critical stages after tanning and dyeing.
It ensures that leather stays soft, strong, and flexible as it dries.
The fats and oils form a molecular film around the protein fibers, acting as internal lubricants.
Leather Fatliquor 5.0 brings this same process to leather restoration.
It ensures the leather is not just “looking good on the surface” but structurally rejuvenated from within.
Leather Primer Adhesor 73 by Leather Doctor® is a compact resin primer designed to smooth, seal, and enhance adhesion before color coating.
Adhesor 73 is formulated and designed to:
Smooth and seal leather surfaces.
Enhance adhesion for color coating.
Build uniform surfaces over rough or abraded areas.
Assist in removing deteriorated finishes.
Reactivate aniline dyestuff to some extent.
Aniline Staining Dye 21 by Leather Doctor® is a new-generation, water-based transparent staining dye based on tannery science principles designed specifically for absorbent leathers, including:
Aniline leather
Nubuck
Suede
Aniline 21 Key Features:
Transparent and brilliant staining effect:
Enhances the natural beauty, depth, and character of the leather grain or nap rather than concealing it.
Lively, rich color:
Produces more vibrant and vivid results compared to most conventional liquid dyes.
Superior lightfastness & fade resistance:
Offers better UV stability and longer-lasting color than standard liquid dyes.
Water-based & leather-safe:
Compatible with Leather Doctor’s tannery science-based care system, ensuring no harm to the leather’s structure or pH balance when used as directed.
Flexible color shading:
Can be diluted with distilled water or Leather Hydrator 3.3 for lighter, custom color shades.
Purpose
Aniline Staining Dye 21 is formulated for:
Re-dyeing faded aniline leathers
Reviving color on nubuck and suede
Creating uniform or shaded effects while allowing natural markings and grain to remain visible
Aniline Gloss Coating Dye 76 by Leather Doctor® is a next-generation transparent surface coating dye designed for vivid, bright color coverage.
Unlike traditional dyes that penetrate leather, this dye forms a surface coating, delivering enhanced color intensity and uniformity. It's especially effective when applied over bronzing-stained dye effects like Aniline 21, or over existing finishes to revitalize and enrich leather surfaces.
How Does Transparent Aniline Coating Dye 76 Work?
Layered Transparency
Like watercolor painting, color intensity builds up with each layer. The more layers, the deeper the color.
Overlapping Strokes
Applying strokes on top of each other increases color depth, enabling shading and visual richness.
Diluting for Lighter Shades
To achieve a lighter or more subtle tone, dilute the original dye with the 'Clear' component.
Always Test First
Conduct a color test before full application to confirm the desired outcome.
Test Application Method
Different tools and methods can yield varied results. Always test your application approach beforehand.
Recommended Tool: Airbrush
For best consistency, use an airbrush with 80 to 100 psi pressure.
Other Methods
Varnishing brushes or folded towels can also be used but may produce more artistic or varied results.
Two Shading Techniques
Method 1: Airbrush
Apply fine, even coats with a Paasche airbrush for a smooth, professional finish.
Method 2: Hand Brushing or Padding
Use brushes or padding for a “salvage” look, emphasizing artistic or antique-style shading.
Pre-Mixing with ‘Clear’
Mix with 'Clear' before application to control the starting intensity.
Depending on the tool used, the finish can range from clean and uniform to uniquely shaded.
Leather Protector B by Leather Doctor® is a pH 3.2 non-stick, rub-resistant conditioner that enhances smooth leather’s durability while providing a soft, buttery feel.
