A special printing ink formulation based on cationic dyes is developed for digital printing of acrylic fabrics using a conventional inkjet printer. In order to investigate the contribution of color gamut boundary of printer colorants to printing efficiency, customized color targets containing 3164 color patches in 25 different hues were generated. The printed color patches were then fixed through steaming for 30 minutes followed by washing with hot soap and water and finally drying. To show the influence of dye fixation on colorimetric changes as well as color gamut boundary of samples, the L*a*b* values of color patches before and after fixation process were compared. Results demonstrate that color saturation of samples is enhanced dramatically after the dye fixation process. In fact, 3D color gamut of color patches has been drastically expanded as a direct consequence of adsorption to absorption transition. Additionally, dye fixation changes the structure of printed image from halftone superimposed dots to contone superimposed dyes. Strictly speaking, during fixation process, colors inside the halftone dots diffuse through the interfacial area to make the individual printed dots integrated. This is in analogy to the chromogenic photography films and dye-sublimation thermal transfer processes by which contone images are produced. Moreover, dye fixation improves the washing fastness of digitally printed acrylic fabrics to the level comparable with the traditional screen printing method.