The high-definition color laser plotter CLP-300 was developed with the main purpose of using digital color' image data to create color originals for printing reproduction use on color photographic materials. It uses three, laser light sources: argon ion (AO, green helium-neon (green He-Ne) and helium-neon (He-Ne), to continuously' modulate beams of blue, green and red light in response to image data, simultaneously scan-exposing each photosensitive layer of the color photographic materials at a maximum resolution of 80 lines/mm and a maximum. speed of 1200 lines/minute, thereby recording a continuous tone color image on the photographic materials. Through the use of a green He- He laser, this unit is able to use light wavelengths that more closely match the color sensitivity of photographic materials and can therefore provide a wide gamut of reproducible colors. In addition, the CLP-300 can also perform color and gradation conversion, basically using a look-up table method for both, in order to change either 4-color YMCK image data for printing reproduction use or computer graphics and other 3-color BGR image data into the 3-color YMC image data for color photographic materials, thereby achieving superior color and tone reproduction.