Keystone View Company
Changing Fixation from 7 to 4 requires 11 1/2 prism diopters of Positive Convergence. The Keystone Eye Comfort and Depth-Perception Series.

Changing Fixation from 7 to 4 requires 11 1/2 prism diopters of Positive Convergence. The Keystone Eye Comfort and Depth-Perception Series.

Public Domain

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Artist Keystone View Company(American, active 1892–1949)American, active 1892–1949

Artist Underwood & Underwood(American, active 1882–1940s)American, active 1882–1940s

CultureAmerican

Titles

Changing Fixation from 7 to 4 requires 11 1/2 prism diopters of Positive Convergence. The Keystone Eye Comfort and Depth-Perception Series.

Dateabout 1930

MediumGelatin silver print, stereograph

DimensionsImage (Each): 3 1/16 × 3 in. (7.8 × 7.6 cm)
Sheet: 3 1/16 × 6 in. (7.8 × 15.2 cm)
Mount: 3 7/16 × 6 15/16 in. (8.7 × 17.7 cm)

Credit LineGift of Malcolm Daniel and Darryl Morrison

Object number2021.555

Not on view

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Department

Photography

Object Type

PHOTOGRAPHS

ProvenanceMalcolm Daniel and Darryl Morrison; given to MFAH, 2021.
Inscriptions, Signatures and Marks

Printed, mount recto, left: KEYSTONE STEREOSCOPIC SERVICE // SKS // COPYRIGHT UNDERWOOD & UNDERWOOD, INC.
Printed, mount recto, top center: EC // 3
Printed, mount recto, top right corner: B01
Printed, mount recto, right: KEYSTONE VIEW COMPANY // SKS // OFFICE AND STUDIOS // MEADVILLE, PENNA. MADE IN THE U. S. A.
Printed, mount verso: THE KEYSTONE EYE COMFORT // AND DEPTH PERCEPTION // SERIES // For the Development of Comfortable Vision // and a High Degree of Depth Perception // // E. C. 3–V32931 Changing Fixation from 7 to 4 requires 11 ½ prism diopters of Positive Con//vergence. // // KEYSTONE VIEW COMPANY, Meadville, Penna. Printed in U. S. A.

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