Chemical Preparations for Incorporation into, or Application to, an Artist's Drawing on Paper to Render the Work Areas of the Drawing Absorbent of Ultraviolet Light Whereby to Adapt the Drawing for Reproduction by a Photoengraving Process Wherein the Highlight Areas on the Negative Are Cleared of Screen Pattern by Exposure to Ultraviolet Light Reflected by the Non-Work Areas of the Drawing, Said Preparations Being in the Following Forms: (a) a Liquid Preparation (Devoid of Any Fluorine or Flu...