Great Britain 1900 ½d colour trial, SG213varGreat Britain 1900 d colour trial, SG213var. A very fine unused example with original gum printed in blue green on unwatermarked paper. A very scarce Queen Victoria colour trial. In 1900 the colour of the "Jubilee" issue was changed to green to conform to U. P. U. guidelines. The ink used for early printings contained lead chromate. This compound is poisonous and so was replaced by a mixture of Prussian blue and zinc chromate. BUY NOW: Order online,