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Ink Pooling

Custom_Grafx

New Member
I have tried everything I know to get rid of this ink pooling on my VS-640.

- heaters
- feed rate
- try on different media
- different profiles (including using custom made with my i1)
- different heat settings
- uni/bi-directional
- ink limits (total and individual)

My previous machine did not have this kind of problem - and if/when it did, I could quite easily adjust for it and fix it.

It's usually because there is too much ink for the media to accept. I don't really want to go below total ink of around 170% or so. I tried printing at a total ink limit of 100% which can't get you dense colours, to see if it would stop, and it makes a huge improvement. So I'm guessing I've isolated the problem to ink/substrate rather than a printer problem?

Any help would be appreciated.
 

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That looks really odd. What media product are you using to produce this? It appears more like the results you would tend to get when printing on a media who'se chemistry is incompatible with the ink set being used. Any additional info you can provide would be helpful (RIP, media product, resolution of print, etc).
 

Custom_Grafx

New Member
That's some Hexis, but it happens on avery, aslan, any gloss white vinyl pretty much.

Ink: Ecosolmax
Printer: VS640 double cmyk config
RIP: versaworks
Print: 40degrees
Dry: 45degrees
Quality: 540x720 high speed (does it on standard too though).
 

Colin

New Member
A digital temp & humidity sensor is a good thing to have in the shop. They can be had cheap - just got one for $25.00

I think the printers like to be in the 40% humidity range.


*shrug*
 

jens

New Member
start raising the heathers. i had simulair problems on my mimaki. and if possible put a delay between the passes.maybe try changing the resolution to less (300dpi)
 

toli13

New Member
Although you said that you had an eye on the individual ink limits, for me it looks like an issue of to much ink in single channels. In most media settings I've seen the settings for C and M are to high. I think, for 540x720 a limit of around 80 % for C and M would be a good starting point.
And I'm thinking about this CCMMYYKK-thing. I've never worked with such a set up, so all I can assume is speculation. May be, there's to much ink laid down on the vinyl from spraying each colour twice in one pass. Ok, the machine is made for this set up. But possibly the vinyl can't handle that much ink in one pass. What if you limit the channels to somewhat around 60 % and see what happens. Just an idea. For example, I've made a profile for vinyl at 1440x1440 where the limits for the channels are set to 40-55%.
If you look at the numbers of the linearisation strip in VersaWorks, what is the max density value you have measured? Just click on the darkest patch. Below the Lab values you find the density. Ideal would be to get chroma values instead of densities, but to figure out where the error is, the density values are better than nothing.
Tilo
 

Custom_Grafx

New Member
Although you said that you had an eye on the individual ink limits, for me it looks like an issue of to much ink in single channels. In most media settings I've seen the settings for C and M are to high. I think, for 540x720 a limit of around 80 % for C and M would be a good starting point.
And I'm thinking about this CCMMYYKK-thing. I've never worked with such a set up, so all I can assume is speculation. May be, there's to much ink laid down on the vinyl from spraying each colour twice in one pass. Ok, the machine is made for this set up. But possibly the vinyl can't handle that much ink in one pass. What if you limit the channels to somewhat around 60 % and see what happens. Just an idea. For example, I've made a profile for vinyl at 1440x1440 where the limits for the channels are set to 40-55%.
If you look at the numbers of the linearisation strip in VersaWorks, what is the max density value you have measured? Just click on the darkest patch. Below the Lab values you find the density. Ideal would be to get chroma values instead of densities, but to figure out where the error is, the density values are better than nothing.
Tilo

Thanks Tilo,

I'm going to take into account what you have mentioned, and am going to try going for the best looking maximum in the calib chart.

On the sp300v it was around the 80% mark, but looking at my chart printed at 85.80.85.80, above the 60-65% area, the boxes actually begin to bleed into each other - which I guess is not a good thing!

I'm retrying at 55.55.60.65 and it's looking alot better... let me put a quick profile together - it won't be 100% accurate because of drying times, but let's see if any improvements.

Will keep you posted.

Thanks,
John
 

Custom_Grafx

New Member
wow, what a difference! Obviously the double cmyk could be the reason behind this. I'm halfway through profiling... went with around 45.45.60.60... am printing target charts now. It's looking about 80% better already on the target charts.

Fingers crossed!

When I have some time this weekend I might fine tune all my profiles again based on this 'discovery'.

Thanks Tilo
 

Custom_Grafx

New Member
Ok, here's another test using the new profile. Opinions?

I feel it's alot better. Definitely no where near as bad. I might actually even decrease the individual ink limit a little more.

I'm using 42.42.60.60 and a total ink limit of 160%.
 

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toli13

New Member
Hm??? A total ink limit below 200 %? That means, that for example Red can't be made of 100 % M + 100 % Y and will possibly be looking muddy or brownish. What happens, if you decrease Yellow to 50 % and set a total of 200 %? Usually I have a total ink limit of about 220-270% for glossy vinyl, but my machine has a CMYKLcLm set up.
I have attached a screen shot of the MediaExplorer. Look for the darkest patches of C, M Y and K. Try to set your individual ink limit down to a value you finally get a density of somewhat about 1,8 for C, 1,6 for M, 1,2 for Y and 1,8 for K. This density oriented workflow isn't perfect, as I said, but within VersaWorks you can't measure for Chroma.
Tilo
 

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toli13

New Member
Not very high densities, especially for M and Y. Have you tried to print a few swatches of primary colours? Just to check if you can print nice looking reds and greens and so. May be, with these low values you are cutting the gamut of the printer.
 

Custom_Grafx

New Member
Thanks I'll check it out. I did a couple of random PMS and the matches were very close. Which PMS do you suggest I do a check on? Maybe I'll do a 185C and a 355C?

Yeah you could say night shift I guess... it's 1.30am.
 

Custom_Grafx

New Member
I'm in the middle of a 7 metre print at 1560mm print width, very solid background colours, blue and green. They are looking great. No banding whatsoever, and no pooling. They are both PMS colours and the match is pretty close! The green is 348C, the blue is 654C, and there is yellow 123C as well - also very close. The print before this was a 322C and was also a very close match.

So far, happy :)
 

toli13

New Member
Just print a large red patch of 100 M + 100 Y. If this looks muddy and not colourful, then the limit of M or Y or both is to low. Also it would be interesting, what a Roland tech says about this ink set up. May be, there are known problems and a workaround.
 

Custom_Grafx

New Member
Yeah, I let him know yesterday, so he's aware of it - told me to try his 'sample' media thinking it's a media problem - but it was happening on 2 or 3 different brands. After tonight, it looks pretty obvious that there was too much ink.

after this print is done I'll try that 100/100 test and see how I go.
 
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