Hi, good night. Well, we have a Mutoh Value Jet 1620, and have been dealing with two different troubles, grays were printing as red-purple-ish and a lot of vibrant blue colors as violet. I've been wasting a lot of time trying to catch the problem, and yesterday finally I solved it. let me tell you all about this, maybe it will help you as well. 1.-Be sure all your work is CMYK and not RGB, RGB is for light, I mean, tablets, cellphones, monitors, etc. CMYK is for ink, 2.-The main trouble is the color profile, I have a Mutoh Valuejet 1624 (I use FlexiSIGN Pro to RIP, using Arlon Vinyl, obviously, there are some Arlon profiles, that honestly work decently, but not with gray and blue, so after trying more than 40 profiles I found this one that works really good, VJ-1624 Magic GFPhoto 240 720x720 Graphics 2.icc, change color correction to "Use linearization only", color mode CMYK (variable dot), Dither: SO Diffusion, with those changes the gray color its been printing super nice, and also the blue, is blue, not purple or violet. Hope this can help.