xc540 - 400% coverage looks clean, calibration doesn't fix green gray

[wreeper007]

Recently upgraded to flexi from versaworks for both our printers (HP FB700 and XC-540).

Started calibrating everything and it went perfect for the HP.

The xc on the other hand didn't go well at all.

I have had issues with green grays for a while, and we thought moving to a unified rip with better color management would solve it.

Start to calibrate and I notice that the ink coverage test area is still very good at 400% coverage. It shouldn't look like that, it should be an unrecognizable blob.

So I decide to replace the dampers and captops (since they haven't been replaced for the 2 years I've been here and most likely were still original parts). That didn't seem to change anything.

So I decide to poke around a little. In flexi, when calibrating you have the option to print a gray balance test print as well. I print it, calibrate with it, then print a confirmation piece (along with a before piece). The green shift starts around 25% gray on the un calibrated piece, and about 35% on the calibrated piece.

But, if I mess with the coverage setting I can get it to shift up to about 45%.

That, to me, tells me there is an issue with the density of the ink being delivered.

I ran this through my dad (retired electrical engineer for GE) and we have a couple ideas. The first is maybe its just bad pumps not sending enough ink (but the dampers are filled and on long runs there is no starvation banding). The other idea, which I am leaning toward more sadly, is there is some electrical issue with the heads and their discharge of ink.

So now I'm kinda stumped because I can't find any articles that address this specific problem, or even know the specific terminology to describe it.

Thoughts?

TL;DR - XC-540 prints green grays, calibration process shows no loss in quality at 400% ink coverage, dampers/captops replaced with no change. Adjusting ink limits shifts the greening but does not remove it.

 

[ImpactSignCo]

This is an oldie, but a goodie. We used to have the XC-540. We changed to an XR-640 with the light black ink cartridge and it has done wonders for us as far as printing grays and beige.

 

[oksigns]

What do your rendering intents look like? I have a profile that can throw out 290% but I don't use the calibrated setting under the rendering intents so that may explain it?

 

[wreeper007]

The roland article never worked even when I was using versaworks.

I haven't played with the rendering intents. I just use the flexi calibration wizard for it.

I'm trying to get rid of the green cast, but I'm wondering if the cast combined with the 400% usable coverage isn't indicative of an actual mechanical/physical problem.

 

[wreeper007]

Perceptual for the CMYK art.

 

[ImagePress]

We've found that the best for us to address this issue is to tweak our transition curves (light cyan and light magenta blends). Making sure those are just so helped with our grays tremendously.

 

[wreeper007]

We've found that the best for us to address this issue is to tweak our transition curves (light cyan and light magenta blends). Making sure those are just so helped with our grays tremendously.

Link to the process? I'm a quick study I just need the info.

And when I did the LcLm part during the profile it looked correct.

I think I will verify that the dampers are filling properly. If they aren't then it looks like I will try a pump or 3.

 

[splizaat]

ur VS540i with light black helped a ton, but we never really struggled too bad with green grey...it always tends to shift blue/greenish a hair, but I've walked down the streets and wonder how sign shops get away with some of the crap green prints they pass off as a black and white photo.

Try adding 1-2% Magenta in your grey. Or click the magenta slider up one or two clicks (or blue down one or two) and it evens it out quite a bit.

 

[eahicks]

on our SC545ex I tend to shoot for nearly a purplish hue in most greys. I have a few swatch colors I use if printing on this thing. By the time they get laminated, they are more grey, since most lam's add a tint of yellow, which exaggerates the green/grey.