GRENADA 1970 QUEEN ELIZABETH II PROFILE COLOUR TRIALS IN BLUE
Queen Elizabeth II profile colour trials in blue, numbered '5.' and '4.' with differences in contrast, prepared during the thermography experiments for the Pirates issue. Ex Bradbury Wilkinson. Scarce. Generally fine. SG367var-370var; SC345var-348var
Note: Bradbury Wilkinson experimented with thermography in an attempt to cut escalating engraving costs, but the trial was short-lived as the depth of shading offered wasn't deemed acceptable
