Here's some interesting quotes about dilutes in the history of the doberman breed:

"In the period before World War I, a large number of blues of high quality were shown. A judge's report for 1910 speaks of the imposing picture made by the Dobermans of both the blue and red colors, which delighted both judges and spectators because of the entry of first-class animals. At that time these colors seem to have surpassed the black and tans in quality, showing greater symmetry and elegance." Milo G. Denlinger, _The Complete Doberman Pinscher_, Denlinger's, Richmond Va, 1953.

Fawns also appeared in the early history of the breed, and have been recorded since 1912 -- only 13 years after the first standard was written. They have been accepted in the standard since 1969, and many people supported fawns much earlier than that.

An interesting quote from Gruenig himself, a large figure in earlier years of the breed:

"It is indeed a matter of regret that the various breed organizations will not tolerate this beautiful fawn color...Our Dobermann could only profit by permitting this color to assume its rightful place in the spectrum of the breed."  in Joan McDonald Brearley, _The Book of the Doberman Pinscher_, TFH, Neptune City, NJ, 1976.

Otto Goeller, one of the founders of the breed, also wanted these colors accepted:

"Otto Goeller wanted these other colour combinations to be recognised. He refrained from taking the necessary action as he feared that it would fail, even though there appeared to be some support for this move. The main objection seems to have been that it would have necessitated the provision of additional classes in which they could be judged, for the different colours were judged separately rather than competing together against one another." Jimmy Richardson, _Doberman Pinschers Today_, Howell Book House, New York, 1995, p. 143,  MIlo G. Denlinger, _The Complete Doberman Pinscher_. Denlinger's, Richmond, Va, 1953.

"Gruenig, and most of his associates wish to recognize the isabella color. In this country there are a few persons who favor isabella, and more that favor the related blue. Blue, and isabella, are dilutions of black and liver respectively. The breed standard, like many other breed standards is inconsistent in recognizing the dilution factor in combination with black (producing blue), and not recognizing the same genetic factor when it chances to combine with liver (producing isabella, termed by admirers of the color, fawn)." p. 174, MIlo G. Denlinger, _The Complete Doberman Pinscher_. Denlinger's, Richmond, Va, 1953.