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advanced Ink limits in Onyx - How to evaluate charts

Discussion in 'RIP Software & Color Management' started by hazartilirot, Nov 3, 2018.

  1. hazartilirot

    hazartilirot Member

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    Sep 23, 2018
    Ukraine
    Good day!

    Is there any body who can explain step-by-step how to evaluate charts of advanced ink limit. Where should I begin? I've read a manual that Onyx support provided but I'm confused... I also tried to find video that shows a practical example, but I didn't succeed. They never explain the evaluation of advanced ink limit on a fresh-printed sample.

    Should I begin evaluating my print from Bleed check chart first? How to decide which value would be close to ideal?

    The result of my ink limits is always propellers....

    Thank you.
     

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  2. AF

    AF Active Member

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    Dec 8, 2013
    Ventura, CA
    It’s pretty simple. Take a sharpie and circle the highest value in each section that doesn’t have issues. Choose the lowest circled value as your total ink limit. Adjust from there as required.
     
  3. hazartilirot

    hazartilirot Member

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    Sep 23, 2018
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    Well, as an example:

    A1 - 145
    A2 - 145
    A3 - 145
    B1 - 170
    B2 - 170
    B3 - 170
    C - 210

    or the same when I put values like that
    A1 - 170
    A2 - 170
    A3 - 170
    B1 - 170
    B2 - 170
    B3 - 170
    C - 210

    The Black and Chroma set automatically, however the values are 100% and 25% respectively. The results - propellers.....

    forgotten to menton, it's a laminated banner.
     
  4. AF

    AF Active Member

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    Dec 8, 2013
    Ventura, CA
    Not sure what you did, but if you have the option to limit your ink before printing the chart, set it to 250. You should have linearized before printing the chart so the information is meaningful. In your list, you have 145 as the lowest value so that may be the ink limit for your media. It seems low and may limit gamut more than you want. Next step would be to print and read patches before building your profile.
     
  5. DSGI

    DSGI Member

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    Oct 18, 2010
    Kent, WA
    The values you provided seem very low. We use eco solvent and UV printers for banner in a relatively high resolution and pass mode (12 to 16 pass and at least 720*1440 for resolution), and this results in us typically reducing our individual ink channels (CMYK plus any extra colors the printer has like O,G,R,etc.) - sometimes as much as 50 percent. Once we do a linearization, we want to see spectral density continually increase in a straight line. If you look at density measurements and see the color channel flatten then you are not gaining anything by printing that channel higher than the percentage where the channel changes from linear growth to plateau. Finally if this is done correctly we typically see a total ink limit between 260 and 400. Based on the numbers you posted for your TIL, it makes me think you have your individual channels too high and are over inking for no gains (basically your limits are higher than where the plateau starts for the channel).

    I typically like to see a lower total ink limit in exchange for a larger gamut (gamut is defined by how much each of your individual channels max), I also like to print test charts of our two color builds before I do the total ink limit to make sure I have strong builds to allow for a very large gamut). The reason I do that is if you use a rich black build of 40,30,30,100 (or something close to that) you would only need 260% to reach your rich black. Many of the higher ink limit combos (like 80,80,80,100 for example) don't result in different colors, so if you restricted your individual channels too much, you limit your gamut size in exchange for more potential builds in the shadows (which in my opinion isn't really that beneficial because you might be able to reach the same value with a lower channel build anyway).

    Another thing you can do, if you want to target a specific reference color profile, such as US Web Coated SWOP, you can look up spectral densities for each channel and limit your inks to those densities or as close as you can to those densities. This should push your TIL higher.

    Try those and report back if you get better results. The forum members might be able to make better suggetions with your feedback.

    Thanks!

    P.S. this was posted by my phone and my auto-correct always inserts typos, I apologise in advance!
     
  6. hazartilirot

    hazartilirot Member

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    Sep 23, 2018
    Ukraine
    Okay, I don't have photographs of the banner I talked...... However I intentionally stopped creating a profile at Advanced Ink Limit. Here's a part of photograph I've taken today:

    https://ibb.co/cMJBf0
    https://ibb.co/eXhF7f
    https://ibb.co/eb9v7f

    Cotton canvas 1440x1440 16 passes.

    As far as I can judge the material behaves well at values of 400. The inks don't bleeds.... am I correct in my assumptions? I can visually distinguish the difference between 395 and 400. If I confine values at 300 does it mean I would narrow the gamut?

    https://ibb.co/edrmDL
    https://ibb.co/gVvrf0
    https://ibb.co/kHra7f


    I just don't understand how to evaluate A1, A2, A3, B1, B2, B3..... Should I more focus on bleeding or the first black column which doesn't change with increasing values.....????

    The "C" row - dunno how to evaluate at all..... I just can't get it.....

    I always try to look at bleeds between those rows.... and take the most even and crisp one though the laminated banner has texture..... which might make me think that there are bleeds..... the banner is really cheap....)))))))

    Thank you for helping anyway.... :)
     
    Last edited: Nov 6, 2018
  7. DSGI

    DSGI Member

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    Oct 18, 2010
    Kent, WA
    That looks pretty good, one thing to consider is where you limited your individual ink limits, what was your per channel ink limit? Also, since you have such a high ink limit for TIL it makes me think you used a contone driver vs. halftone driver, which is fine but basically the contone driver (if I'm correct) is a driver that is produced by the printer manufacturer with predefined ink limits already set when you choose a media type (such as Banner, or Canvas, or adhesive backed vinyl, etc.). Epson provides contone drivers and they work pretty well for the most part, however I can do a halftone driver profile, set my own ink limits and produce a more voluminous gamut profile than if I use the contone driver.

    When I evaluate ink limits for TIL I look at two things:
    1) print flaws due to over inking - such as bleed or splotchy patches
    2) Does the patch set continually change/improve as I go up in ink limit

    Typically I try to set my total ink limit where we have no bleeding/print flaws but also where we get the max change - so if you see no bleeding or print flaws + plus your density keeps increasing to 400 - then 400 is where your ink limit should be set. This all depends on:

    1) Printer
    2) Media
    3) Print Mode
    4) individual ink limits . --> if these are set too high you will have a lower TIL and if they are set to low you will have a higher TIL

    Again, I find the best results when I push my individual channels enough to give a great gamut but still restrict them enough so my TIL stays above 250, but your milage will very depending on the factors listed above. The main reason I try to for a TIL of 260 - 300 is beacause over 260 or even 300 I feel most of those builds can still be accomplished at a lower build (as mentioned in my earlier post) but you can't get a single color like Cyan of 85% with a build so if you limit your individual channel of cyan to increase your TIL you are technically NOT wrong, but you are giving up your gamut size for more possible shadow tones - but there is no guarantee you the shadow tones you can make with the higher TIL you couldn't have made with a lower TIL.

    Does that make sense?

    Let us know about the driver type you are using plus your individual limits and that will help answer if you are limiting your self.
     
  8. ColorCrest

    ColorCrest Active Member

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    Dec 11, 2017
    So Cal
    You have some helpful information to work with from previous posts, however there might be something more to be aware of in earlier steps of the profiling process.

    1) In the first step of ink restrictions, try to find the option to plot the chroma graph. In the attached image example, notice “hooks” of cyan and magenta ink channels. These are mild hooks and only slightly wasteful of ink even if imaging very high volumes of work. Beware of anything more severe and learn about “chroma hook” and color gamut limits.
    http://onyxgfx.com/userguides/legacy_profiling_guide.pdf

    2) In the second step of calibration, be sure to use the option to print the “Onyx Quality Evaluation.pdf” found somewhere in your Onyx folder. The print will show the current color balance of your settings so far with no ICC profile influence. Ideally, the print should show good density from rich blacks through neutral grays and detail throughout up to white. Although the print may not be perfect or even significantly color-biased, the last step of ICC profiling can most likely correct these failings to satisfaction. Keep this print as a calibration reference against the last step of ICC profiling and other media calibrations and to also track trends over time.

    3) The third step of ink limits is usually forgiving. When you find the time, you might try settings of very extreme limits of both light and heavy just to see for yourself what happens with any given media. If the first two steps of profiling are within reason, you might be hard pressed to create propellers using ink limit settings. Also in your favor, know some media can have a very high tolerances of ink load.
    https://www.lfpc.es/wp-content/uploads/2013/05/Using_the_Ink_Limit_Wheel__Hive.pdf

    4) When you’re finished creating the ICC profile as the last step, be sure to print the Onyx Quality Evaluation.pdf again only this time “all profiles on” should be used of course. The result should be an ideal print compared to the previous version which was printed without the ICC profile. Again, keep this print for future reference.

    Ideally, all calibration prints from any media should appear similar and especially all finished prints using ICC profiles should appear similar among like materials and definitely without color bias among them.
     

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  9. hazartilirot

    hazartilirot Member

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    Sep 23, 2018
    Ukraine
    Is there any undisclosed training videos on the subject (profiling)? Could any body share with me by uploading onto https://fex.net

    Thanks!
     
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