Under a raking light...

The appraisal of an art piece is not an easy matter. Experts resort to a multitude of methods, ranging from using a magnifying glass to employing complicated chemical tests to establish the nature of a tiny, but mysterious stain. The range of terminology used in defining the results is vast, perplexing and tediously detailed. Here are some examples of simpler and most common faults or merits usually found in photographs, books and drawings. The only rule of thumb in the process is that all evaluation or condition reports should be performed 'under a raking light'...