The effects of printhouse humidity and temperature on shade depths of three typical colors, black, blue, and yellow, are investigated. Cotton, silk, and nylon 6,6 fabrics were used for this study with reactive, acid, and acid dye inks, respectively. Our study found that a change of 10% relative humidity or 10 °c could cause 20% or even more differences in shade depths, although all the other printing conditions were the same. The mechanisms for the variations in shade depths with humidity and temperature are proposed and the possible approaches in minimizing shade variations are recommended.