The Trial Color Proofs
These were made at various times for many different reasons. The normal purpose of the proofs was to choose the color for the finished stamp. Since trial color proofs served as examples of the engravers work, they were very carefully made. Ink was applied to a steel die or plate with the proof being taken on a piece of dampened India paper to which often was added soft cardboard. The final product left the India paper impressed into the card. The proof may subsequently be soaked off its cardboard backing.
PR1TC- Bright Red (untrimmed- showing plate holes) & Large Die Trial Color Proof- Black
Color proofs exist in may colors and shades that are difficult to tell apart when "stand alone."
Note: Myself and fellow collectors are convinced PR16TCCarmine(12¢), PR30TCBlack($3), PR31TCVioletBrown($48) do not exist (I've written to Scott Publishing). While referenced by Frank Braceland, the PR30TCBlack in his collection turned out to be a black Atlanta trial color proof.
PR4TC Black---- PR4 Black Counterfeit
Trial Color Proofs should not be confused with Counterfeits which were also printed in different colors. However only one Trial Color, the PR4TC Black actually matches the colored Counterfeits.