PMS vs Spot best practices for various presses

[Widmark]

Sorry if the title is wide-ranging or the subject well-tread. I'm often releasing files where I'm not sure what the final printing method will be, or I know the artwork is going to a variety of processes, usually HP Indigo and/or production inkjet/UV presses. In discussions/research it seems the best practice is to keep everything Pantone and let the vendor's libraries handle the conversion. Occasionally we'll break from Pantone and come up with our own GRACoL breaks, which we proof in house and hope the vendors can match.

What I'm specifically wondering about today is how various RIPs/DFEs handle Pantone Black. For instance if I release a file with elements set to Pantone Black C to an Indigo, does it treat it as 100% K, or will it try to "match" Pantone Black C by coming up with some kind of rich black mix? I know technically Pantone Black is just "black", a single ink, but I know how Adobe does a screen preview of Pantone Black C by making it a bit fainter than just 100k. Does anybody know specifically what an Indigo will do with Pantone Black?

I'm looking at our Printfactory library right now and seeing the LAB values for Pantone Black are L 17.1, a 1.3, b 2.0 which makes me wonder if the RIP would then cross render it to a rich black CMYK break, instead of just printing 100% K.

I'm going to send some test files but wondering if anybody knows or has any thoughts?

 

[jwheeler]

I just looked it up in our Fiery spot library and it says it will print the CMYK as 53.5/56/57.5/87. This is for a Konica Minolta digital press. I also looked up the CMYK conversion on the Pantone website and it gives the values: CMYK 63/62/59/94. So it appears Pantone Black is not just 100% K. The operator would have to manually go into their spot library on the RIP and change it. I think your safest bet is to use 0/0/0/100 if that's what you want. If you want a rich black, I use 60/40/40/100 for offset. As for other Pantone's, I always prefer that the customer leave it as the Pantone name. That way, I can adjust it in my spot library at the RIP if it's not coming out correctly.

 

[Widmark]

Great, thanks. Yeah that seems to make sense and that's what other vendors have said about leaving the colors as Pantone. We just occasionally prefer 4c GRACoL values of flat colors if it's for something that otherwise would be way out of gamut or is just doesn't have a pantone match.

I'm not sure that I want 100% black over a rich black, just trying to understand what it might do. Will try to test multiple options (100k, Pantone Black, Rich Black)

 

[Widmark]

This is weird, I just ran a test print, we use printfactory driving a Canon with a GRACoL queue. I sent Pantone Black C, "Black" (as selected in InDesign, which is 100 k) and a standard Rich Black break. For some reason the "Black" actually pooled up! I've never had this happen. Everything is properly linearized and I've definitely printed "black" to this proofer before without this happening. Any idea why this would happen? Probably a question for the digital printing board?

 

[jwheeler]

What do you mean by "the black pooled up"?

 

[Widmark]

ok I see in the printfactory editor that it's "overprinting" the "black" type, which sort of makes sense, except it's never done that before, we've certainly proofed things with elements set to black that haven't pooled up with another color.

 

[Widmark]

What do you mean by "the black pooled up"?

Like when you haven't set the ink limits correctly, you can see the ink all smudgy and drying poorly. I'm looking at the seps in printfactory and in InDesign and it seems to automatically treat "Black" as overprinting. I know that's standard but it's not selected in attributes. It just seems strange to me because I've definitely proofed things set to "Black" along with other colors and this hasn't happened before.

 

[Widmark]

OK, in ID prefs. it defaults to have "black" set to overprint, regardless of attributes. For this project I'll just create a 100k swatch. I'm still confused why this hasn't caused any issues in the past.

 

[DYP]

Not sure why you say it defaults in ID when it is an option you choose. How you want blacks handled is something you need to consider for every job and specific elements in that job in the Attributes settings.

 

[scotts]

Each presses DFE can be set on how to handle blacks. Whether it be 100%K or Pantone Black. You have to choose. And how to handle to the overprints.

Maybe in your case, someone was messing, or I mean adjusting the settings for a specific job, and forgot to turn it back to your shops "default" setting. But you should be able to create different workflows for different jobs, that have different settings.

 

[Widmark]

Not sure why you say it defaults in ID when it is an option you choose. How you want blacks handled is something you need to consider for every job and specific elements in that job in the Attributes settings.

In ID Preferences>Appearance of Black, there's the setting "Overprinting of [Black] Swatch at 100%" which defaults to be checked on, so anything set to black will be set to overprint. This is not reflected in the attributes panel.

 

[Widmark]

Each presses DFE can be set on how to handle blacks. Whether it be 100%K or Pantone Black. You have to choose. And how to handle to the overprints.

Maybe in your case, someone was messing, or I mean adjusting the settings for a specific job, and forgot to turn it back to your shops "default" setting. But you should be able to create different workflows for different jobs, that have different settings.

There's nobody but me messing w/ the DFE and I don't make any changes to it. We've definitely sent jobs to this DFE with type set to [Black] swatch and it's never had this behavior before so there's something I'm missing. I would also think that with the proofers ink-limiting and proper set-up (handled by a color consultant, not myself) that it wouldn't do that? The DFE tries to match the Pantone and replicate the look of the black overprinting said pantone but it should stay within the limits?

 

[DYP]

In ID Preferences>Appearance of Black, there's the setting "Overprinting of [Black] Swatch at 100%" which defaults to be checked on, so anything set to black will be set to overprint. This is not reflected in the attributes panel.

I have "Overprinting of [Black] Swatch at 100%" setting unchecked and it stays that way. For a new document it never defaults back to checked on.

In my document when creating new elements or text the "Overprinting of [Black] Swatch at 100%" setting is reflected in the attributes. Changing the "Overprinting of [Black] Swatch at 100%" won't change anything in elements already in the document only new elements.

 

[Widmark]

I have "Overprinting of [Black] Swatch at 100%" setting unchecked and it stays that way. For a new document it never defaults back to checked on.

In my document when creating new elements or text the "Overprinting of [Black] Swatch at 100%" setting is reflected in the attributes. Changing the "Overprinting of [Black] Swatch at 100%" won't change anything in elements already in the document only new elements.

I meant defaults as in when you install the program, not automatically turning back on. I've always had it on and have never changed it, thus my confusion over this new behavior at the proofer.

However, my attributes panel does not show 100k black as overprinting unless manually selected to do so.

 

[Correct Color]

Here's the way it works:

Any spot color is any RIP is two things, a name and a L*a*b* value. In just a quick check in Photoshop, the L*a*b* value for Pantone Black in the Solid Coated library is L=17 a=1 b=3.

So that L*a*b* number is what the RIP will attempt to locate in the destination printing color space -- which is whatever printer profile you are using -- and then print. Again, from a quick cursory look in Photoshop, in SWOP -- just as a for instance -- that comes out to C=68 M=63 Y=67 K=72. In other color spaces, those values will vary, because it's the L*a*b* value that's constant; that's the whole point of color management.

If -- if -- what you want is 100%K or some amount of K only, keep in mind that that's not what you're asking for if you specify Pantone Black. Your black primary is not going to be that. What you're specifying when you call for any spot color is the L*a*b* value of that spot color. How close you come to achieving it is dependent on how well the profiles you're using match what your printer actually prints.



Mike Adams
Correct Color

 

[DYP]

There ia another way that (custom) Spot Color Libraries work depending on your RIPs capability and that is to specify output values to your printer. For example RIPs with the ability to printout color charts that specify what the output values are that can be visually matched to a Pantone Book or even a paint chip and then can be saved as spot color libraries.

In my experience both with wide format and sheet fed digital presses one can often match or more closely match high gamut color that is simply not possible using color management from LAB values. Different RIPs will implement this differently. For example the Fiery DFEs use "SPOT ON" which ties these values to an output profile for a specific paper. While some Wide Format RIPs I have seen will basically do what amounts to being that same as the Replace Color options where color management for that specific color is bypassed and the specified output values are used. In both approaches these values will not be the same for different media. Using the LAB values through color management would be my first approach but where colors are difficult to match I then move on to setting output values for Spot Colors.

 

[Correct Color]

There ia another way that (custom) Spot Color Libraries work depending on your RIPs capability and that is to specify output values to your printer. For example RIPs with the ability to printout color charts that specify what the output values are that can be visually matched to a Pantone Book or even a paint chip and then can be saved as spot color libraries.

In my experience both with wide format and sheet fed digital presses one can often match or more closely match high gamut color that is simply not possible using color management from LAB values. Different RIPs will implement this differently. For example the Fiery DFEs use "SPOT ON" which ties these values to an output profile for a specific paper. While some Wide Format RIPs I have seen will basically do what amounts to being that same as the Replace Color options where color management for that specific color is bypassed and the specified output values are used. In both approaches these values will not be the same for different media. Using the LAB values through color management would be my first approach but where colors are difficult to match I then move on to setting output values for Spot Colors.

I'll just say that I have never been a fan of this at all.

In fact, my usual response to people who ask about these procedures/processes -- and yes, most RIP's have some version -- is that all of them are basically work-arounds for inaccurate profiles.

When reproducing color with a printing device that is producing color with primary colors, it's always a good idea to remember that at some point, you're simply going to run out of ability to print certain colors on certain media. That's a mechanical/physical fact. You can do any number of things to get to the very edge of these capabilities, and the commands to do this when dealing with digital printers are always digital, but the process is still physical and no amount of digital manipulation can change that.

It's also a fact that whatever the outer ranges of these color printing limitations are with any device on any media with any inkset (the gamut, of any device, for short) there is no device out there in any condition that can print any color that is not contained in the L*a*b* color space.

So specifying any color to any RIP as a L*a*b* value is specifying it in its purest, most uncorrupted digital form. And since there is no L*a*b* value that cannot be printed by any printer, there is no combination of output values that cannot be defined as a L*a*b* value.

So the "output values" are always the RIP's interpretation of a specified L*a*b* value in the destination color space, which is the printer profile. If the profile matches what the printer actually prints, that result will be the closest match you can get.

Now of course there are lots of colors that need to be matched that aren't in any color library, but the best way I've found to match them is to measure them, get a L*a*b* value, and then give that L*a*b* value a name in the RIP, and run that color as a spot color, just like any color named in a library.


Mike Adams
Correct Color

 

[michaelejahn]

I would like to suggest that - some RIPS ( I I know Adobe RIPS ofer this ) well, they have a setting where you can have black "overprint" up to a certain point size - and then trap when it is over that point size. Of course, I would assume that this would be for a RIP that is set up to make a set of color separations ( but sounds like you are printing digitally, so, not separation, but composite ) - but in any case, while the idea of adjusting black ink overprinting in composite rips for type might not be available, I share this only so that, if it were you might have a peek at that setting.