Sorry I forgot to mention the printer is a JV3 and I am printing unidirectional.
I never really print 4 pass only maybe when it is a banner, short term or going on a racecar or something otherwise it is almost always 8 pass. Just noticed a little banding today while printing some small logos and couldn't remember if that was common on 4 pass or not.
This is normal. We don't typically ever print in 4 pass, it is difficult to stop banding using our bulk ink and it the printer can actually put down more ink than the lines can handle. 4 Pass is giving the ink alot less time to dry which I think you'll find is alot of the banding problems. If you were to put a pass dealy you could probably take the banding out, but at that point just use 8 pass if you aren't getting banding
4 pass is pretty much useless. I'm convinced its there just to throw a high production speed number out there for the purposes of marketing the machine. We run bi-directional on almost everything and mostly 8 and 16 pass. Keep in mind, you need to have profiles that are specific to your pass count.
It depends on what kind of banding you're seeing. It there are very thin light or dark lines between each pass, that's just a media compensation issue and is easy to adjust. If the passes themselves are different from one to another, that's an ink or profile issue, harder to fix. For what it's worth, with the right profile, 4 pass can be made to print just fine. We've got a good profile for Ultraflex banner material, so all of our banners are printed at 4 pass bidir with no banding. We also get great results on some other banner materials, matte vinyl, and some images on gloss vinyl. Often, if the image has alot of solid color, gloss vinyl gets bandy, but overall, we get good results. About half of everything we print is printed in 4 pass bidirectional and it's all perfectly sellable. It just takes time to figure out what media will take that much ink that quickly and what profile and heat settings are required to achieve it. But the JV3 is capable of producing good prints in that mode.