Leather spew would give a gummy feel – and would not only appear on the grain, but the grooves as well quite consistently.
Mold would gives off a musty smell again the spotting pattern does not suggest mold growth.
These natural grain spotting pattern suggest the leather finishes as “Nubuck”.
Nubuck is top-grain leather that has been sanded or buffed on the grain side or outside to create a velvet like texture or nap. You may check this “finger writing effect” from the un-used area (turn a cushion). They are also easily darken when wet (test with a wet cotton swab on hidden unused areas).
If this leather is positively identified as Nubuck then the grain-spotting coloring could be intensified by Hydrator-3.3. Nubuck is aniline dyes through; the sanded tip may be more prone to fading and drying of the fatliquor that cause this phenomenon. Hydrator-3.3 will activate the dormant dyestuff from below to resurface to a degree and
Fatliquor-5.0 revert the dryness that saturate the color intensity at the same time.
Roger Koh
Leather Care Consultant
www.LeatherDoctor.com
[email protected]
Information - Nubuck Leather Care from - http://www.leatherdoctor.com/servlet/the-Kit-%E2%80%93-Nubuck-Leather-Care/Categories
Nubuck is top-grain cattle leather that has been sanded or buffed on the grain side, or outside, to create a velvet like texture or nap. It has the characteristic of a slight nap, with the softest “hand” or tactile feel. Although nubuck is aniline dyed through and sanded it is commonly finish with a surface dye sometimes incorporating micro-pigment to cover up some natural blemishes. It looks similar to suede, but the difference is that suede is created from the flesh side of leather, whereas nubuck is created from the grain side of leather. As both nubuck and suede are napped leather, it is often incorrectly identified as suede. Leather is both hydrophilic and oleophilic, nubuck especially with its open nap absorbs both water and oil more readily, than any other smooth leather. It is generally more expensive than suede; fashion types include embossed, oil and wax pull-up effect. Fatliquor plays an important role when comes to maintenance to both reduce ingress of waterbased and grease stain; plumps the leather with fullness, reduces creases, and wrinkles. Leather protein-fiber component is amphoteric therefore, a leather-safe (pH 3 - 5) care product system is highly recommended to keep them clean while maintaining their chemistry integrity.