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Using photographic patents as a source of information

Trying to find relevant sources of information for the surface relief properties of gelatin, Paul A. Lehman finds an unusual source to find answers: The patent archives. He shares his findings here. Each patent provides detailed information on emulsion ingredients, preparation and processes, which can be reproduced in a suitable home darkroom laboratory. Writer and photography / Paul A. Lehman Color and Gelatin Relief Emulsions U.S. Patents Issued to Michele … Read more

CarbroGel example print. Mission Door, San Antonio, Tx by Paul A. Lehman. 8"x9". Negative 1975. Print 1999.

Novel Experimental Approaches for Making Pigment Prints

After struggling with making Carbon Prints in the late 1990s, Paul A. Lehman explored alternative approaches to making pigment prints.   Writer and photography / Paul A Lehman, MSc. It is well recognized that the Carbon Print is considered by most as the quintessential historic pigment process. However, the process of making a carbon print is challenging and requires skill and patience. I struggled through this process in the late … Read more