Laser subtitling entails the burning of the subtitles into the surface of the film print letter by letter, frame by frame, subtitle by subtitle. Since any mistakes become a permanent part of the film print and cannot be corrected, we exercise the utmost of care when creating our subtitle files. Since polyester film material is heat-sensitive and subject to warping, it does not allow the clean burning of subtitles. For this reason, the film prints are washed after subtitling to remove residues, leaving the subtitles crisp, white and clearly visible. The burning process leaves small bulges around the edges of every letter, which appear as black borders during projection, making laser-burned subtitles much more readable than those made using outdated chemical processes. Following the completion of the subtitle lasering process, each film print undergoes final technical quality control.