Polaroid Corporation

Charles E Jandrue, Sr

David P Waller

Myron S Simon

Marcis M Kampe

David C Whritenour

Elbert M Idelson

A novel class of bridged indicator dyes is disclosed which possess absorption in the infrared region of the electromagnetic spectrum. These bridged indicator dyes are useful as light-absorbing, pH-sensitive optical filter agents in diffusion transfer photographic processes adapted to be performed in the presence of ambient light and to diffusion transfer products useful in such processes. These indicator dyes will also find utility in titrations and other analytical techniques and products where pH-sensitive indicator dyes are employed and absorption of infrared is useful.

Photographic products and processes

Novel benzaldehydes of the formula: ##STR1## Where n.sup.1 is the integer 1-8 and each OR.sup.1 group is hydroxy or a protective group which can be converted or removed to provide the dihydroxyphenyl moiety. The benzaldehydes are particularly useful as intermediates in the preparation of yellow azomethine dye developers.

Growing community of inventors

Norwood, MA, United States of America

Charles E Jandrue, Sr