Nearly all keyboard instruments (virginals, spinets, harpsichords, clavichords, etc.) as well as lutes and guitars have one or more ribs glued to the bottoms of their soundboards for statical or acoustical reasons. Up to now any documentation of these ribs made it necessary either to open the instrument -- i.e. Painstakingly remove the soundboard which could take days -- or x-ray them which requires special training and equipment that would not ordinarily be available to a normal restorer. After due experimentation in the photographic studio of the Institute für Farbenchemie of the Akademie der bildenden Künste in Vienna, I would like to introduce a simple photographic process of documentation, which any restorer able to handle a camera can employ under certain circumstances. Almost all the above-mentioned instruments have somewhere one or more openings to let out the sound (the process can only be applied with such openings) -- either in the soundboard itself in the form of a rose or near the keyboard in the so-called dam. A series of flashes are shot into the inside of the soundbox through their soundhole thus lighting up the soundboard to such an extent that the ribs on the bottom can clearly be seen as shadows and making visible any faults in the wood as well as the direction of and the distance between the annual rings in the grain of the wood. If there should be more than one soundhole, the others must be closed tight permitting no light in.