After developing the film, he created three separate negatives and exposed one of the three to a red filter, one to a green filter, and the last to a blue filter. Porter then created three matrices by shining light through each negative onto its own sheet of matrix film. To make the print, Porter then put the one with the red filter into the blue dye, the one with the green filter into the red dye, and the blue filter into the yellow dye. The absorption of the dye depended on the thickness of the paper, where the thicker paper absorbed the most dye. After four minutes and the dye had completely transferred, he then carefully removed the die, washed it, and carefully rolled the next die into place. He was able to change the hue and contrast of different prints by changing the acidity of the dyes and then repeating the process of dipping and rerolling on one or more dies. When it was finished, it would create a color image