Background

Doppelganger grew out of a research project aimed at improving print standards. In February 2003, Bill Birkett and Chuck Spontelli discussed the problem of setting up digital proofing systems to commercial print standards. The GRACoL guidelines were a start, but they didn't provide enough information. Creating tone curves required more than just densities and dot gains. Seeing this need, they began a collaborative research project.

The first goal of the research was to determine what information was required to characterize color printing. To answer this question, numerous tests were done matching proofs to presswork. This research led to a new color matching technique which is both simple and powerful. The basic ideas are explained in a technical paper, which was presented at the TAGA annual meeting in San Antonio in April 2004.

A by-product of the research was software for producing tone curves and device link profiles from colorimetric measurements. A printer, who had helped with the research, was having problems matching color proofs provided by a key client. With a simple test, the problem was solved by creating a tone curve for that client. This success led to further work with the printer — a carefully planned program to standardize color within their plant.

From this early work, it became clear that both printers and print buyers could benefit from the fruits of the research. Doppelganger was founded to help clients solve their color problems, and to promote color standards within the printing industry. The Optimal Method, a technique for calibrating print processes, is based on our work in this field. This technique has its own web site, which includes information about our open source color tool kit.

William B. Birkett

Bill Birkett is a graduate of the University of Michigan with degrees in mechanical and electrical engineering. He founded Precision Color, a prepress firm, and worked as technical director, production manager, and sales manager, at various times, during a 32 year career with Precision Color. He has an extensive knowledge of color, workflow and computer programming, which he used to develop our unique software tools. He now works full time as a print quality consultant, helping both printers and print buyers eliminate waste, and increase profits.

O. Kay Birkett

Kay Birkett is a graduate of University of Michigan, with a degree in geology, and Walsh College with a degree in marketing. She worked as a quality engineer for a big three auto company. More recently she has worked in sales and marketing functions.