 The company took the first steps towards developing the View-Master stereoscope after a chance meeting, at the Oregon Caves in 1938, between Graves and William Gruber, an organ maker of German origin trained by Welte & Sons and an avid photographer, living in Portland.The View-Master used disk-shaped "reels" which are thin cardboard disks containing seven stereoscopic 3-D pairs of small color photographs on film, and its individual eyepieces immersed the viewer into the scene more fully than previous stereoscopes.Mayer and Gruber had both developed devices for viewing stereo images, but Gruber had developed the idea of mounting tiny pieces of Kodachrome color transparency film into reels made from heavy paper stock, for viewing in a stereo slide viewer designed for the reels.