Ink Limits

[jasonx]

Hey guys,

Making some profiles.

Can someone please clarify for me when setting the individual ink limits before printing the measurement chart do I set them all to 100%?

Once this is done I take a measurement. Everything besides yellow looks good. Yellow is attached. At this point should I manually adjust the points or reduce the yellow ink limit and repeat the process?

Also the total ink limit chart what things should I be looking for in terms of Total Ink Limit? Is it the point it starts to bleed or the point where the colours are their most vibrant?

 

[Neil]

Hi Jason,
if you're lucky, eye4clr or Bly might wander past and be able to tell you exactly what to do. I haven't used Versaworks profiling so I'm not much good to you.
But we had a good discussion on another forum where eye4clr in particular was most helpful at detailing the steps involved. Unfortunately all that info is now lost so I can't post a link to it!

I can however post this link from another thread here in case you haven't seen it:

http://support.rolanddga.com/docs/D.../Manuals and Guides/VersaWorks3_Profiling.pdf

It appears to me:
The first chart is unrestricted, after printing that you would decide where to set the individual ink limits based on looking at where the ramp stops getting any darker.
You can actually measure the chroma and lightness with your spectro but not sure if you have the ability, so you may have to do it by eye.
You can get fairly close just by looking at the magenta, cyan and black ramps but the yellow is harder to see.

Typically somewhere around 80% is normal - so the last 20% gets clipped off and won't get printed when you do the linearization chart.

Then you can manually smooth out any spikes in the curve.

Then you set your total ink limits based on the max amount of all colours the vinyl can handle at once.

 

[rfulford]

You can actually measure the chroma and lightness with your spectro but not sure if you have the ability, so you may have to do it by eye.

This is the best way to to perform your ink restrictions. This is easy enough to accomplish with Measure tool. If you download profile maker from Xrite, it comes with Measure Tool which will run with limited functionality without the dongle.

Open Measure Tool

Connect to your Spectro

Click on the spot tool and change the measurement mode to LCH.

Read the darkest swatches of your lin target and find the patch where the chroma peaks. Where the Chroma peaks is where you set the restriction.

Set the black channel according to L(luminance) not Chroma.

Print a new chart with the restrictions in place and linearize

 

[jasonx]

I think thats the whole step I was missing. I have that versaworks pdf and was measuring the individual ink limit chart with my i1.

With the measure tool in profile maker can I use the individual ink limit chart that versaworks prints out for measuring? or is it a file within profile maker I have to load into my rip and print off?

 

[eye4clr]

This is the best way to to perform your ink restrictions. This is easy enough to accomplish with Measure tool. If you download profile maker from Xrite, it comes with Measure Tool which will run with limited functionality without the dongle.

Open Measure Tool

Connect to your Spectro

Click on the spot tool and change the measurement mode to LCH.

Read the darkest swatches of your lin target and find the patch where the chroma peaks. Where the Chroma peaks is where you set the restriction.

Set the black channel according to L(luminance) not Chroma.

Print a new chart with the restrictions in place and linearize

BING! we have a winner.

This is exactly how to do it. Unlike me when i explain this online, i always forget to mention to setup the Measure Tool spot reading dialog to use the more current DeltaE math (the last in the list) and as you mentioned, change the measurement from LAB to LCH so you get the all important Chroma deltaE.

I'm always amused to see how often you can see how having excess ink can give you LESS chroma.

Oh yeah, almost forgot....yellow is the "wild card" color that you don't measure but use to help with grey balance relative to C and M.

Sometimes you can cut ink to the point of being just short of 1 deltaE down from the peak. This way you're taking out as much ink as you can without perceivably reducing gamut. Sometimes this can be substantial. YMMV.

Happy profiling.

 

[Rooster]

I have no experience with Versa works for profiling, but that yellow curve in the original post has a a couple of awful spikes in it at 10% and 90%.

If you ever see the curve flatten out that far or reverse direction like that, reprint or re-read your targets. It's not right.

 

[jasonx]

Cheers guys,

Just to make sure I'm doing this correctly and thanks for your patience.

Printed out my linersation chart from versaworks with all limits set to 100%.

Open up the Measure Tool.
Goto Spot Measurement.
Set on colormeteric.
Color Space = Lch
Set to Delta E (only there are other options)
Read the darkest patch as the reference.
Read the patches as samples:

Results:

Reading Magenta
Delta C
100 = 0
95 = 3.5
90 = 3.3
85 = 0.2
80 = 2.3
75 = 2.5

So in this instance when you say chroma maxes out my value is 95% Magenta?

Hopefully I have a proper understanding now.

Thanks for all your help guys so far. Been learning to do this for a long time and only had more time to develop to getting it right lately.

Jason

 

[sjm]

If you are not seeing any artifacting, ie the ink is not bleeding you can safely proceed. It's important to remember ink restriction is a way to make sure that we never put more ink on the media than needed.

 

[Neil]

Read the darkest patch as the reference.

Results:

Reading Magenta
Delta C
100 = 0
95 = 3.5
90 = 3.3
85 = 0.2
80 = 2.3
75 = 2.5

I usually start at the lightest patch and work up the ramp. It seems a bit more intuitive when you compare the reading and see just where it stops making any difference to the deltaE.
Also don't discount using you're eyes.

As eye4clr said, you can't get a true reading for Yellow so once you've set the CM&K, you base your yellow restrictions by trying to acheive a neutral grey CMY ramp. Start by restricting Y to around the same amount as say Cyan. Then linearize and print a CMY ramp. Too green= too much yellow.

 

[sjm]

Seems odd? Is this unique to Versaworks?

 

[jasonx]

thanks Neil,

I'll give it another shot.

 

[eye4clr]

Seems odd? Is this unique to Versaworks?

Not odd as far as i see. Magenta in solvents typically gets restricted the least (if at all). C, Y, and K will vary wildly from media to media.

You're likely to see longer stretches with C where the delta is less than 1. When it start to go larger than 1, back up a bit and voila!

It is also common to see the chroma go UP as you work your way down the ramp from the full 100% patch. At first I thought that Neil's method of working up from the lighter patches was brilliant. Only downside i can see is that you may not find the highest point if there is a long stretch of similar chroma values. But, then again, if there is a long stretch, maybe better off to restrict that out.

Thinking out loud here.

 

[sjm]

Not odd as far as i see. Magenta in solvents typically gets restricted the least (if at all). C, Y, and K will vary wildly from media to media.

You're likely to see longer stretches with C where the delta is less than 1. When it start to go larger than 1, back up a bit and voila!

It is also common to see the chroma go UP as you work your way down the ramp from the full 100% patch. At first I thought that Neil's method of working up from the lighter patches was brilliant. Only downside i can see is that you may not find the highest point if there is a long stretch of similar chroma values. But, then again, if there is a long stretch, maybe better off to restrict that out.

Thinking out loud here.

Sorry but we are still discussing setting individual ink limits or otherwise known as basic ink restrictions? If we have progressed to linearizing and setting total ink limits then the point made is valid.

The reason I thought basic ink restrictions was needed prior to linearizing or setting total ink limits was that it ensured that you don't get so much ink in a 1 or 2 color pixel and that bleeding along with other undesirable artifacting didn't occur.

Think of it as qualifying a media before committing 2 to 3 hours in building a profile.

 

[Neil]

Were discussing the first step - setting individual ink restrictions. Prior to linearizing (calibrating) and prior to setting total ink limits.

The purpose of this is to lop off any unnecessary ink usage beforehand and thereby achieve a better linearization curve. And consequently a better output icc.

Put simply, you print the first unrestricted CMYK ramp, look at it and try to find the point where the colour maxes out (doesn't get any darker).

The principle here is that if a colour looks just as dense at say 80% as it does at 100%, then we don't need the printer to lay down that last 20% of ink. It doesn't alter the perceivable colour any more, so we can do away with it.
So you set that individual ink restriction at 80%.

One advantage is this will save you up to 20% of your ink when you print.
The printer will only lay down as much as is actually necessary - up to that 80% limit.

But the main advantage is the subsequent linearization curve will be more smooth and even because it is based on a true 0-100% gradient ramp.

My last printmode was based on something like C80%, M95%, Y80%, K85% limits.
I needed just about all the magenta I could get. You don't want to restrict things too much - better to leave a little overhead IMHO.

 

[sjm]

Were discussing the first step - setting individual ink restrictions. Prior to linearizing (calibrating) and prior to setting total ink limits.

The purpose of this is to lop off any unnecessary ink usage beforehand and thereby achieve a better linearization curve. And consequently a better output icc.

Put simply, you print the first unrestricted CMYK ramp, look at it and try to find the point where the colour maxes out (doesn't get any darker).

The principle here is that if a colour looks just as dense at say 80% as it does at 100%, then we don't need the printer to lay down that last 20% of ink. It doesn't alter the perceivable colour any more, so we can do away with it.
So you set that individual ink restriction at 80%.

One advantage is this will save you up to 20% of your ink when you print.
The printer will only lay down as much as is actually necessary - up to that 80% limit.

But the main advantage is the subsequent linearization curve will be more smooth and even because it is based on a true 0-100% gradient ramp.

My last printmode was based on something like C80%, M95%, Y80%, K85% limits.
I needed just about all the magenta I could get. You don't want to restrict things too much - better to leave a little overhead IMHO.

OK eye4clr was confused then? Reading from 0% to 100% or 100% to 0% during the basic ink restrictions phase yields the same results. For example finding the highest percentage patch where there is no colour difference.

We'll leave lc and lm out of the equation for the moment or any advanced settings.

 

[Neil]

Yet another pointless interjection from you sjm.
Please either stick to the point or stop interfering. Preferably the latter.

 

[sjm]

Yet another pointless interjection from you sjm.
Please either stick to the point or stop interfering. Preferably the latter.

Neil I asked and you confirmed, we are discussing individual ink restrictions.

Were discussing the first step - setting individual ink restrictions. Prior to linearizing (calibrating) and prior to setting total ink limits.

So address the question or better yet don't go off on a tangent.

 

[Rooster]

It's amazing how little information you actually contribute to these threads beyond just calling other peoples information into question.

What question are you actually referring to in your last post? I've seen no wandering off topic in this thread by anyone except you.

I thought that eye4color's method of using the chroma values from the LCH readings to determine the maximum saturation point of the hue was rather ingenious. You're either just not getting it, or you're just baiting people. After going through this a few times with you now I'm leaning towards the latter. It would seem you're far more interested in pushing people's buttons than contributing anything useful.

 

[sjm]

I have no experience with Versa works for profiling, but that yellow curve in the original post has a a couple of awful spikes in it at 10% and 90%.

If you ever see the curve flatten out that far or reverse direction like that, reprint or re-read your targets. It's not right.

Rooster, basic ink restrictions are what we are discussing and as such it is not linear.

 

[Rooster]

Really? How so?