A Technical Note: Note on “Inverted Relief” In Photographic Illustrations Available to Purchase

The author points to errors in the orientation of photographs illustrating pitting or blistering forms of corrosion which result in incorrect relief perception by the reader. That is, pits appear to be blisters and vice versa. He suggests the reason for this misconception is incorrect orientation of the illustrations with respect to the location of the shadow. It is recommended further that the general policy be adopted of photographing specimens illustrating pitting and blistering phenomena, so that the shadow falls toward the bottom of the paper.