Simulating spot colors with flexo

[gordo]

In a recent Kodak FlexoGlobal webinar "Do more with 4" it was claimed that with "Flexcel nx a printer can reproduce, using just 4 process colors, 72% of the Pantone Plus library with a deltaE of less than 3." Also that with "a different customer - 80% of the Pantone Plus library could be reproduced."

However, on Kodak's Spotless solution poster (downloadable from the Kodak website), the percentage of Pantone spot colors (fewer colors than the Pantone Plus library) that can be reproduced using offset and a 7 colour process with a DE of less than 3 is just 50%.

Basically the claim is that 4/C flexo with flexcel nx has a larger gamut than offset using a 7/C process (72%-80% vs 50% of spot colors simulated) - a 44% increase in the number of Pantone Plus spot colors that can be simulated.

I've reached out to Kodak a month ago about this discrepancy, but so far no explanation.

If you are shown the webinar or see other marketing material that makes this gamut claim, it might be a good idea to ask for an explanation regarding the discrepancy.

best, gordo

 

[John Reveley]

Kodak, like many companies that sell us things, either knowingly or perhaps arrogantly, make claims, which to the folk working at the coal face, know are either impossible or just ignorantly optimistic.
The company I work for, were solely chosen to beta test the NX plates in the UK a few years back, we were told that image files could be treated as litho files, but of course they were wrong. I never cease to be amazed by companies that are at the forefront of supplying services and materials to the repro/printing industry, having such a poor knowledge of the basic facts relating to print, and especially flexo.
Having said that, Kodak NX with digicap is a excellent product when managed correctly.
We are currently checking out Spotless, personally I am unconvinced of the real benefits, at the moment.

 

[conger]

I don't disagree with the comment about sales claims but there might be something else going on. If you look at a Pantone Plus formula guide you can see that most of the new colors that were added are combinations of 3 bases often with black as a 4th ingredient. These colors are lower in saturation than most of the traditional PMS colors and are easier to match in CMYK. Therefore manufacturers can now claim a higher % of achievable PMS colors without expanding the gamut of their devices.

 

[gordo]

If you look at a Pantone Plus formula guide you can see that most of the new colors that were added are combinations of 3 bases often with black as a 4th ingredient. These colors are lower in saturation than most of the traditional PMS colors and are easier to match in CMYK. Therefore manufacturers can now claim a higher % of achievable PMS colors without expanding the gamut of their devices.

Perhaps, but I can't imagine it would enable a 4/c process to deliver a 40% increase in achievable colors over a 7/c process.

If you plot the Lab values of the base Pantone Plus vs Pantone, most of the hues are shifted slightly and only the blue and yellow have a slightly different chroma. I don't think they're that far apart.

I've attached a plot of the different primaries (Pantone Plus is the colored squares).

I've asked for a profile of the 4/C flexo space. Does anyone have a profile of Pantone Plus they can send me? Even a text file of the Pantone Plus Lab values would be helpful.

best, gordo

 

[conger]

If you plot the Lab values of the base Pantone Plus vs Pantone, most of the hues are shifted slightly and only the blue and yellow have a slightly different chroma. I don't think they're that far apart.

Sorry. I wasn't speaking about the base colors. The added Plus colors are generally lower chroma because they have black and/or 3 bases in them.

thanks,
Will

 

[Paul L.]

On behalf of Kodak, please allow me to clarify a couple of statements. First off, the data from the 4/c process flexo trial reported on in the recent webinar was compiled from comparison to the Pantone Plus library-1341 colors. That analysis did, in fact, reveal that 72% of the library could effectively be reproduced with 4/c process simulation at a DE less than 3.
The data demonstrated in the Spotless poster that Gordo is referring to (attached) was evaluated from a select subset of the Pantone library focused on 379 "high chroma" colors. The statistics would obviously be different if compared to the entire library. Secondly, in viewing the attached poster, you will see that the data reveals that the percentage of spot colors simulated printed offset 7/c process with a DE of less than 3 is actually 93%.
I apologize for any confusion that may have resulted in the reporting of this data.
Cheers,
Paul

 

[fiatlux]

@ Paul - What percentage of the Pantone (not Plus) library can be simulated with Spotless flexo? The poster shows 50% of the colours with offset would it be the same? Also, I thought that the percentage of simulated colours on the poster was for all the Pantone colours not just the ones they selected. Is that not correct?

FL

 

[Paul L.]

@ Paul - What percentage of the Pantone (not Plus) library can be simulated with Spotless flexo? The poster shows 50% of the colours with offset would it be the same? Also, I thought that the percentage of simulated colours on the poster was for all the Pantone colours not just the ones they selected. Is that not correct?

FL

I believe that is where we unintentionally created some confusion here...the data demonstrated on the Spotless poster is only in comparison to the selected subset of high chroma colors-not the entire Pantone library.
As far as the flexo trial, the Pantone Plus guide was intentionally selected for comparison simply because it does not include some of the pastel and metallic colors that would be hard pressed to simulate through any form of recipe simulation. With that being said, please keep in mind that the basis for that particular trial was to compare 4/c gamut reproduction capabilities utilizing Flexcel NX plate technology versus competing digital photopolymer plate technologies. Your question is a valid one, however, and although I do not have that data at my immediate disposal, we can conduct an analysis of the data taken from the flexo trial and compare it to the complete Solid Formula Guide for those seeking a more "apples to apples" comparison to offset capability.

 

[gordo]

[SNIP]
As far as the flexo trial, the Pantone Plus guide was intentionally selected for comparison simply because it does not include some of the pastel and metallic colors that would be hard pressed to simulate through any form of recipe simulation. With that being said, please keep in mind that the basis for that particular trial was to compare 4/c gamut reproduction capabilities utilizing Flexcel NX plate technology versus competing digital photopolymer plate technologies. Your question is a valid one, however, and although I do not have that data at my immediate disposal, we can conduct an analysis of the data taken from the flexo trial and compare it to the complete Solid Formula Guide for those seeking a more "apples to apples" comparison to offset capability.

That will be helpful.

I've looked at some new data and it seems to support my concerns.
So, here are some thoughts for any flexo printer considering any vendor's (not just Kodak) solution for simulating spot colors with screen tint builds using 4/C process. Just talking gamuts not the other issues.
• Ask for an ICC profile of the 4/C process that was used to determine what percent of the Pantone or Pantone+ library is in gamut.
• Ask what method was used to determine the deltaE.
• Check to see that the vendor's print condition is representative of your print condition (substrate, screening, SIDs etc)
• Use an application that can compare profiles to each other as well as with Lab text values.
• Ask for a text file of the Lab values of the spot color library. If that can't be given to you by the vendor then have them show you, during a demo, how those values map to the gamut they based their claim on.
• It does not matter what percentage of spot colors are in gamut if the colors you need to simulate are outside of the achievable gamut for 4/C process. So, compare the Lab values of the colors you need to simulate with the gamut of the 4/C process.
• Compare your required spot colors to the gamut.

The comparison can be as simplistic as this:

The large blob is the GRACoL 7 sheetfed gamut (175 lpi gloss coated) From left to right the dots represent: Kodak corporate Red, Golden Gate Bridge terracotta, and Kodak corporate Yellow. All three are clearly out of gamut for 4/C process.

Disclaimer, I happen to think, based on my experience, that the Kodak Spotless solution is, holistically, a better solution than the other offerings for spot color simulation whether 4, 5, 6 or 7 colors. That being said, this is a technical issue so IMHO, it's best to base your decision regarding gamuts and simulation capability on data - not anecdotal information.

best, gordo

 

[Paul L.]

Gordo: I could not agree more with your recommendations for a flexo printer striving to learn what the gamut capabilities are for a particular print condition. Every point you make happens to exist as part of the Spotless Flexographic Solution, and is provided to each printer when a trial print run is conducted. The key point is the capture and understanding of gamut capabilities based on a particular print condition-press, anilox, substrate, ink, mounting tape and plate. The other key is maintaining process consistency and establishing meaningful tolerances to the point that the results can be duplicated.
Nonetheless, it appears that you remain skeptical. As added reference, please allow me to provide a direct quote authored by Ian Hole of Esko that appears in the January, 2013 issue of FLEXO magazine..."With a more controlled SID offering smooth solids and good highlights, more than 75 percent of all Pantone colors can be created by a closely managed set of CMYK inks on the substrate, with an accuracy below 3 DE. Adding O, G and B inks to the pressrun adds another 15 percent of the spot colors and delivers roughly 90 percent of the Pantone book."
Or, perhaps, for a more "unbiased" perspective of current gamut reproduction capability from 4/c process in flexo, particularly through the use of Flexcel NX and similar technologies, you may consider reaching out to Steve Smiley at Smileycolor for his viewpoint and experience.

 

[gordo]

Gordo: I could not agree more with your recommendations for a flexo printer striving to learn what the gamut capabilities are for a particular print condition.

Thanks, you're too kind.

Every point you make happens to exist as part of the Spotless Flexographic Solution, and is provided to each printer when a trial print run is conducted. The key point is the capture and understanding of gamut capabilities based on a particular print condition-press, anilox, substrate, ink, mounting tape and plate.

Excellent.

The other key is maintaining process consistency and establishing meaningful tolerances to the point that the results can be duplicated.

Absolutely

Nonetheless, it appears that you remain skeptical.

Yes, because the claim contradicts my experience in an offset shop and the tests done during the Spotless Solution product development. But I'm happy to be wrong if the data that is the basis of the claim is provided.

As added reference, please allow me to provide a direct quote authored by Ian Hole of Esko that appears in the January, 2013 issue of FLEXO magazine..."With a more controlled SID offering smooth solids and good highlights, more than 75 percent of all Pantone colors can be created by a closely managed set of CMYK inks on the substrate, with an accuracy below 3 DE. Adding O, G and B inks to the pressrun adds another 15 percent of the spot colors and delivers roughly 90 percent of the Pantone book."

Not to be too cynical about it, but if I were Esko marketing and Kodak was claiming 72% of all Pantone colours can be created in 4/C then I would be very tempted to claim I could do 75%. Again, it's anecdotal information.

Or, perhaps, for a more "unbiased" perspective of current gamut reproduction capability from 4/c process in flexo, particularly through the use of Flexcel NX and similar technologies, you may consider reaching out to Steve Smiley at Smileycolor for his viewpoint and experience.

I will do so, and if he grants permission, I will share his experience in a post to this thread.

Thanks Paul for participating in this discussion - so many vendors avoid the conversations in venues like this. gordo

 

[Bill W]

Greetings Gordo,

I have been in the flexo industry since 1981 and have seen a lot of promises. I take all with a big grain of salt until someone can prove otherwise. We use 3 seats of Prinergy, buying our first and second seat from Creo. I also have heard the hype from various flexo oriented vendors of the ability to print high percentages of PMS color using only 4 colors. Could elaborate, but prefer to counter these marketing blurbs with, "there is a sucker born every day" (attributed to George Hull) and "You can fool all of the people some of the time, and some of the people all of the time, but you cannot fool all of the people all of the time" (attributed to Lincoln PT Barnum, John Lydgate and Mark Twain).

Not from Missouri, but sure believe in their slogan "Show-me". In other words don't "market me".

 

[gordo]

So, I've spoken to the Kodak reference site, Smileycolor. They provide colour consultation and professional services to the flexo industry.

The company they tested Spotless on run 150 lip on white poly. As far as they know the data that they got was not used as the basis for Kodak's claim of being able to simulate 72% of the Pantone Plus library.

The SIDs that they ran the Flexcel NX plates at were:
K: 2.20
C: 1.75
M: 1.65
Y: 1.30

Now that's impressive to say the least.
Here's the profile that they sent me superimposed on a GRACoL7 profile.

You can clearly see the larger gamut resulting from those high densities.
The overprint traps are also improved. The comment was that the solid process patches looked like even flat areas of color without any streaks.

They felt that they were covering at least 70% of the Pantone+ library at those densities, however they have not actually measured whether that is correct or not.

In this graphic you can see the Pantone+ library superimposed over both the flexo high density and GRACoL7 standard densities.

In both cases, quite a number of the spot colors are within gamut, but I don't have software sophisticated enough to tell me what the percentage is.

Note that the spot colors that remain out of gamut are mostly in the secondaries - the two colour overprints - RGB.

So, my take away is that the Flexcel NX plates enable flexo 4/C process to simulate as many Pantone+ spot colors as offset printing run to GRACoL7 (however many that may be). The number of Pantone+ spot colors that can be simulated out of 4/C process is increased when SIDs are increased. High chroma spot colors that are in the RGBO quadrant are still out of gamut. Now that I've seen some data, it appears that a larger percentage of Pantone spots are in gamut for a 4/C process than I had previously believed.

If someone on this forum has the ability to actually calculate the number of spot colors that are within gamut for a 4/C process - please contact me off line at pritchardgordon @ gmail (dot) com

best, gordo

 

[Bill W]

My question to Kodak when I discussed higher densities to achieve more PMS colors using only CMYK was, what happens to the integrity of my solids (CMYKRGB) if I want them to meet GRACol numbers. The color from the densities cited in the test in my experience would be too high to achieve a good GRACol match. As an example a Flexo magenta ink at that density, unless a custom mix, would have a positive b value. It would be interesting to see the Labch values of the solids at the densities listed.

 

[Stephen Marsh]

Bill, how visually important is it to have the solid CMYRGB GRACoL values (apart from colour bars)? The curves would be adjusted to be close to GRACoL so that CMYK images would appear close to "regular" presswork.


Stephen Marsh

 

[Bill W]

I am not sure what you mean by "regular" presswork. Some CPC's, including Walmart, via RR Donnelly, have defined specific Labch targets numbers that one has to meet when printing labels for them. They are the same as those in the IDEAlliance G7 How To document. The request for CMYK is to keep L value ≥ 3, a and b ≥2 and the hue angle ≥2°. While one can create curves to gray balance almost any set of CMYK inks, if one does not start with solids that meet the GRACol Labch numbers, I would say that the images would not match a GRACol proof.

I guess if one was using CMYK densities that produced out of spec CMYK Labch numbers, then they could use device links to bend the solids, but then they would have to deal with solids that were "contaminate with other colors.

 

[Stephen Marsh]

What I meant by "regular" presswork was similar to GRACoL or Fogra 39. Kodak provide info on how to setup RIP curves so that the tonality of Kodak Flexcel NX plates can closely match common offset print specifications.