Originally Posted by
Roger Koh
Bruce,
Here is the revised version for your consideration . . .
BMW Black Nappa Leather Seat Refinishing
BMW Nappa leather is top-grain leather, which retains a lot of the original textures and markings of the hide. This semi-aniline leather is first dyed through with transparent dyestuff so that the suede side takes the same color shade as the grain side. A fine opaque micro-pigment is then applied to the grain side to camouflage blemishes or imperfection for a mono-tone appearance. We can consider its finish as half transparent aniline-dyed grains and half opaque micro-pigment sprayed on for a more even appearance, thus befits its name as semi-aniline.
The advantage of restoration and refinishing a semi-aniline over pigmented leather is that the excess dyestuff within the leather structure can be hydrated to resurface to reduce the contrast in appearance between worn, sun-faded, creases and micro-cracks from surrounding areas prior to reduced micro-pigment coatings. Diminishing original average 14% fatliquor (fat and oil) content from aging lightens the color saturation and is replenishable to increase the color saturation. These hydrating and fatliquoring capabilities rejuvenate the leather structure both in appearance and suppleness. When worn, creases, and micro-cracks appearances are less contrasting, less micro-pigment is used. In contrast, more coatings mean producing a lower grade leather. Micro-pigment is a finer and higher quality pigment that is also strong against sunlight fading. This micro-pigment is adjusted with an auxiliary thickener to control flow during fine airbrushing. In a three dimensional airbrushing, a cone shape pattern spray produces better results due to ease of directional control. An artistic technique produces a professional result, and a few light coats with in-between drying produces better results than heavy coatings. The objective is to retain its natural appearance with suppleness for seating comfort and a good feel of hand.
When refinishing BMW Nappa leather, care must be taken not to diminish the grain surface. This applies especially to the use of abrasives during cleaning and preparation steps. Sanding is only performed on the coatings or finishes, sanding to the grains is to be avoided as the coarseness of the grain increases with reduced tensile strength.
BMW Nappa Leather is made for BMW by the German company Bader Leather.
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