The invention discloses a focusing control apparatus applied in an image recording system. A primary mirror reflects light rays to form a first set of light rays to a secondary mirror that has a generally concave shape coupled to the housing. The emulsion includes a mesoionic compound having a thiolate structure or a protonated thiolate structure, and the emulsion is sensitized by an Au compound. The severed edges of the aligned ply strips are formed in mutual linear alignment and do not include projecting triangular patterns, or crenelations. The difference gives the amount of line shortening due to flare, and may be used to calibrate line shortening measurements made using optical measurement tools.