Print quality vs Setup, 6 color or dual CMYK

I think you'll lose a bit on color gamut, but at the same time, if you're mostly doing outdoor billboards and the like, that's not all that much of a problem. And you don't have to stock as many different kinds of ink.

 

i thought 2x cmyk was for 8 heads and printing a larger path on each pass ,purly for speed not for a quality hike.

in colour rip there is the option to run cmyk on a 6 colour machine

as far as ink banding is concerened i think is down to material and profile and a lot of luck.



woolly

 

Light ink channels (light cyan and light magenta) are designed to add realism to highlight areas, such as skin tones etc.

Adding them (lc lm) does little to nothing in terms of adding to the color gamut potential for the inkset and media being used.

What you will get with a CMYK-only ink setup is additional speed, when compared with CMYKlclm ink configuration.

By the way, you would have one printhead per color, assuming that the're using the SP version of the JV3.

Bob

 

If your getting banding its you rip. Thats assuming that all your heads are firing correctly. Its you rip and profile . I do not band at at all ever since I am using the correct profiles.
Talk to Jackpine he helped me out.
Bruce Schurmann

 

Your profile or rip can go all the above. I have a mutoh and have had no issues since Jackpine got me on the straight and narrow. NONE

 

it almost sounds like something called WET BANDING. You may be overloading the Ink onto the substrates. Check your rip settings for the total ink or max ink. Certain substrates can accept more ink load vs. others. Otherwise it is a step or feed issue. If it says its tuned correctly, you may want to consider "de-tuning" it a bit and there could be an improvement with that.
We run CMYK-Lc-Lm on our Vutek 3360. The 6 color DOES increase Gamut with certain colors....try running PMS 116 in 4 color mode, you get a darker more magenta-ish yellow. With the Lm in there, its a truer color to the PMS chips. Try turning off your Lc-Lm heads and running strictly in 4c mode.

 

We have run 6 color 720 var dot 8 pass bi-directional for nearly 3 years and have never had banding concerns. Check your media comp settings with a ripped image, not the test mode. You can adjust them on the fly on your JV3 control panel and see if that helps. I don't think switching to CMYKx2 will fix your problem. Media comp can also be adjusted in your rip (at least in Onyx 6.5).

 

The fourth head is an old fried one. Just a dummy, more or less. Your problem doesn't sound like a damper problem - it sounds more like a profile (too much ink) or a media comp problem. I can't speak about Flexi RIP from experience, but I've heard it is not the best by any stretch.

 

An easy thing to check is switching to single pass mode. If the banding disappears it's due to the inks being laid down differently in each direction.

On one pass you'll get something like KCYMLcLm
and on the return pass you'll get LmLcMYCK

With dual CMYK they set the ink channels to print the same in either direction eliminating this undesirable effect. Like KCMYYMCK.

 

We print only in 6 color mode. You need to check your media compensation under the same conditions as you print. IE take up reel use and heat. Also, you need to adjust the media comp with the aid of a loupe or magnifying aid of some kind. Check your media compensation often, and every time you change media or print a long run.

It could also be a profiling issue as mentioned before. If your ink limits are too high, ink can sort of wick away to the edges of each scan creating the appearance of overlapping scans. You will usually get fisheyes too if the ink limit is excessive.

Your heater temps and the relative humidity in the print room can also be major factors.

In the end, switching 2 dual CMYK probably won't solve your problem. There are certainly valid reasons for running CMYKX2 but this is not one of them.

 

Sorry to dig up such an old post but how does one go about changing a 6 color + Metalic + White to dual CMYK? I am currently looking at a VS540 machine with that ink configuration however I want the dual CMYK purely for speed. Is it as easy as switching out the ink cartridges and carrying on or do I need to do something more.

Thank you

 

At the very minimum you'll probably have to flush the LC and LM. White and whatever metallic ink are in there are almost certainly going to require replacement of the ink systems for those colors. The odds of being able to recover them is probably pretty slim, especially if the printer has been sitting idle.

 

Thanks Derbycity for replying again The guy who I'm buying it from told me that the metallic and white have been used daily to prevent them from clogging. Assuming that's true, what is the actual process of flushing and when you say replace the ink systems does that include the tubes. dampers etc?

 

You can flush the LC and LM lines by running cleaning solution and possibly recover them. No guarantee. Same for the metallic and white ink, except that it's almost certain that you'll have to physically replace every component of the ink delivery system for those colors.

I've never done it, but from what I understand, the motherboard dictates the colors, so the printer won't recognize the LC, LM, W, and metallic channels as CMYK. There's a workaround, but I'm not 100% what it is. Could potentially be replacement of the motherboard?

I think there's a forum specifically for Roland printers, you may want to check there. I'm sure there are some folks that have experience doing this conversion.