This paper presents a low-cost method of constructing a UV illuminator, which is considered an important component of a gel documentation system. The procedure involves using a smallest-possible UV lamp in the UV illuminator instead of conventional 4 UV lamps.A comparative analysis of images produced by using the commercial gel documentation system and our prototype was performed using MATLAB. Despite the use of only 1 UV lamp, the proposed system demonstrated a similar imaging performance compared to the image quality of a conventional gel documentation system equipped with 4 UV lamps.