Need Help GCR in Caldera

Mark Allibone

New Member
Hi all,

I’m just wondering if somebody can explain the differences within the GCR tab during profiling in Caldera v13.

basically I’m printing direct to textiles on a DGEN H12 and my pure black is great but the machine is clearly over inking as a rinse test shows run off on the black areas a little too much.

i have 4 settings to adjust:

1. black start - i understand this and is set correct.

2. Black Max
3. Max Ink
4. GCR Amount

2-4 are the variables that I’m sure i need to adjust to get my ink levels just right for the media i’m using but if anyone can explain these further it may help me make better decisions before i go and just randomly try settings.

thanks
 

Pauly

Colour Guru
Before you start askng questions abouot GCR. i suggest you learn what GCR is and what it does.

and GCR wont fix over inking.
ink limits will.
 

Mark Allibone

New Member
Thank you. Yes i have been reading about it. My global ink limit is as far as i can drop it without starting to lose the colour punch.

im learning all the time but i came to this forum as i don’t have any people around me to ask for help on such matters.
 

Mark Allibone

New Member
I've never quite understood how "max ink" works in relation to "ink limit" setting from previous step. Any insights?
This was one of my main issues. Im going to run some tests this week and try to discover what occurs now I understand some more. Ill post my results if they are successful
 

Mark Allibone

New Member
I've never quite understood how "max ink" works in relation to "ink limit" setting from previous step. Any insights?
I thought id post my results. So i rebuilt the profile for the flag media that was using way to much black and in the GCR dialogue box i reduced ‘max black’ down to 50% from 90% and ‘max ink’ down from 300% to 200%.

I knew this would be too much but i wanted to see where the boundaries were.

i was please to see a radical reduction on black as print was more washed out. So i know that these variables are reducing black usage. I just need to find the sweet spot now .

Its interesting because you can see the GCR working in the colours further from the neutral axis like dark blue when you make the adjustments.

Still plenty to learn but its looking good!
 

chinaski

Member
I thought id post my results. So i rebuilt the profile for the flag media that was using way to much black and in the GCR dialogue box i reduced ‘max black’ down to 50% from 90% and ‘max ink’ down from 300% to 200%.

I knew this would be too much but i wanted to see where the boundaries were.

i was please to see a radical reduction on black as print was more washed out. So i know that these variables are reducing black usage. I just need to find the sweet spot now .

Its interesting because you can see the GCR working in the colours further from the neutral axis like dark blue when you make the adjustments.

Still plenty to learn but its looking good!

Just a tip, if you need a bit more saturation, try adjusting rendering such that saturation is negative.

Linearization and ink limits are more important steps and if your results are way off, I'd go back to the beginning. What are your global ink limits? Black point with pure and rich black? Caldera will give you a default Dmax of 99%. This is more times than not too high. Lower these once curves start to flatten, or even prior if you know your media cannot handle alot of ink.
Screen Shot 2021-04-29 at 9.33.39.png
 

Mark Allibone

New Member
Thank you for this information. My settings are set to default in this window but thats interesting what you say about a method for saturation reduction.

My global limit is at 45% so quite low but the media is flag and i know some users go right down to 20% on this but you see a drop in rich colours under 35%.

What i am doing seems to be working fine to solve my issue as I’m nearly at a sweet spoke to controlling the black.


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Mark Allibone

New Member
Hi All,

Just wanted to double check something. I have been struggling after ink limiting on Caldera to reduce black. I bring the global limit down to the minimum i can allow without starting to lose depth of colour, but the black doesn’t seem to follow and is clearly over inking.

Now there is a choice under the ink limit slider in the photo attached. When our print provider engineer set this profile he left the setting on ‘preserve black ink’ which seems to clearly explain my issue as the limiting i am performing is not touching pure black.

If i were to select ‘full clip’ i assume this means limit all inks the same?

Thanks for your time


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