Within the central Rendezvous room of the 1904 Craftsman style Riordan Mansion there are two unique sets of windows. Each window consists of seven black and white photographs with a translucent frosted glass background. The photographs depict Southwest scenic landscapes and portraits of Native Americans with a diffused lighting background.

The original windows were prepared by binding the photograph transparency in contact with a piece of finely ground glass. They were then coated with a matte varnish, thus creating a photograph on glass. The seven images provide an inspiring addition to the rustic mission decor of the room's interior. John K. Hillers, the prominent photographer who accompanied John Wesley Powell on his second expedition to the Grand Canyon in 1879, is the author of the spectacular photographs used in the windows. Hillers had met the Riordan brothers, Michael and Timothy, during archaeological excavations at Walnut Canyon in 1885. He was later commissioned by the brothers to produce the windows for the adjoining family room of their twin mansions in Flagstaff.

 In 1993, an ambitious project was begun at the Riordan Mansion to address the deterioration of the glass and images. The damaged windows were faded, cracked, with pieces of glass missing. A conservation assessment in 1984 revealed that the images have been damaged by fungus growth and chemical instability through 90 years of fluctuating humidity and condensation. Due to the advance stage of fungus damage there was no hope of restoring the original glass images.

A decision was made to attempt to locate the original negatives and reproduce the images on modern materials and to replicate the exact images, sizes, and wood window. In addition, modern materials and technology were incorporated to replicate the original images.

The John K. Hillers window transparencies at the Riordan Mansion and those at the National Museum in Washington, D.C. are the only known surviving examples of Hillers glass photographs. The reproduced images in the Rendezvous room at Riordan Mansion State Historic Park now provide the visitor with a greatly enhanced experience of the original 1904 "Arts and Crafts" period setting.