Examine a single, restricted area of an aged item from various perspectives while it rests beneath a moveable lighting source. Do not attempt to clean it; rather, observe whether the surface appears darker, smoother, rougher, brighter, or more worn. Then, look for similar characteristics in a concealed section, such as the underside, the interior of a hinged lid, or an area that lies beneath a decorative element. Such brief comparisons are more practical than a rapid judgement that each and every discoloration is either worth preserving patina or removable debris.
Patina is the alteration in a surface that occurs as an object gets older from handling, exposure, and natural material characteristics. For metal surfaces, patina can occur as oxidation or change in color; for wood surfaces, as mellowed color, softened finish, and friction wear where an object was held repeatedly; for leather surfaces, as darker colors and smoother friction wear at edges and at grips. Patina has no single characteristic appearance, and brown coloration does not signify age. Staining, smoking, polishing, or intentional aging can mimic patina at first glance.
Dirt usually rests on or in a surface; it does not occur as an aging characteristic of the material. Dust may lodge in recessed carving and molding; sticky substance may attract dirt; old wax may become cloudy or inconsistent in color. Recognizing dirt, however, does not indicate whether a cleaning method will not harm a surface. A solvent that affects one type of finish may discolor another type, erode hand-painted design, affect applied gold leaf, or remove signs of previous use. Even plain water can stain paper, expand unstabilized wood, or cause brownish spots in a glaze crack in porcelain or pottery.
Damage is a physical change that causes the weakening, removal, or alteration of a material. Chips, cracks, losses, abrasion, loose veneer, torn woven fabric fibers, broken book bindings, and loose corrosion can be recorded in condition reports. Look for sharp, exposed edges, loose movement, lifted edges, loose powdery substance, or cracks running through a surface. In some instances, polishing and cosmetic repairs will hide damage from view; photograph a damaged area before any restoration is attempted. Filled chips in ceramics, replaced hardware fittings on furniture, and areas with hand-painted retouching may look tidy but still be relevant to a condition assessment.
A location clue helps you separate these surface conditions. Wear occurs naturally where there is frequent handling, such as a drawer handle or chair arm, the top corner of a book, or the base of a handled object. Dirt collects where surfaces are hidden by molding or raised carving. Randomly placed scratches that cover both high and low areas may be the result of careless handling or intentional aging rather than use. Inspect various areas of an object rather than relying on a single, striking example. Patterns that repeat themselves are more telling than one-off stains.
Write down your observations with impartial language. Rather than describing “patina,” write something such as “surface has brown coloring that is darker in color and lighter, smoother in texture in areas of friction wear near the handles.” Instead of stating an item “needs to be cleaned,” describe the area of discoloration as “darkened deposits, concentrated in recessed carving, and not known to be stable or water-resistant.” Note that a damaged area is a “long, fine crack extending from a top edge, and a small chip in corner veneer” as well as “green loose powdery material concentrated around a metal hinge.” You can later compare your notes to the object, a provenance list, and known, confirmed examples.
Ask yourself three questions before deciding what you believe is happening to a surface change. Is the location of a change one that would be typical of usage of the object? Is the change one that can be cleaned off, has altered a surface, or removed material? Is a proposed cleaning or handling likely to destroy an item or make it worse? Where uncertainty exists, do not touch a surface; document it carefully. The best clue you will find may be the clue you find because you didn’t rub it off.