In addition to heat, grainy solids can also be attributable to several other factors:
1. Drop Accuracy - Perform a bi-directional calibration, and slow down the carriage (head) speed. Both of these can serve to improve dot placement accuracy.
2. GCR settings in the Media Profile - For non-Roland Color System colors, including RGB, CMYK, and Pantone colors, Versaworks uses the ICC Profile. Too much GCR in the ICC will cause peppering in quartertones and highlights. GCR settings are defined in the output ICC profile.