Great Britain 1958 2d light red brown "Dollis Hill Phosphor Trial”, SG573varGreat Britain 1958 2d light red brown "Dollis Hill Phosphor Trial, SG573var. A very fine perforated left hand marginal block of eight on gummed crowns watermarked (upright) paper, with a single green phosphor band at left. Although similar to the issued stamp (SG613), the colour is much paler, the printing courser and the phosphor reaction afterglow much stronger. The phosphor band is printed by photogravure and clearly visible in normal light on both