Luminous Landscape Forum
Raw & Post Processing, Printing => Colour Management => Topic started by: Marco Ugolini on March 26, 2010, 03:34:13 am
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Let's say that you have an Epson inkjet (any of them), and that you are trying to print on it from Illustrator (any version) a color proof of a specific CMYK image (with both raster and vector elements in the artwork).
Let's say that you are trying to cross-render on your inkjet the printing conditions of US Web Coated (SWOP) v2.
Let's also say that you have profiled your inkjet printer as carefully as you know how to. Also you don't use a RIP — just the Epson driver. (Note: I am not inquiring whether I should use a RIP, so I ask that the discussion not be derailed onto that topic. Please bear with this scenario just as I describe it.)
Of course, since you are attempting to produce a color proof, you use the Absolute Colorimetric intent in Illustrator's Color Management tab along with the correct custom profile for your inkjet printer.
So my question is: why does the finished print not show the paper tone simulation that I know should appear on it?
("Should", because I know that the inkjet paper I'm using is brighter than the substrate used under US Web Coated (SWOP) v2 print conditions.)
In Photoshop it all works as expected (the workflow being: printer profile with AbsCol in Photoshop's Print CM tab + "No Color Mgmt" in the driver). The Photoshop print distinctly shows the expected simulation of the destination profile's substrate. But no substrate simulation is visible in the print made from Illustrator when using the exact same workflow (or any workflow, for that matter).
What am I missing? Or is this a bug?
Thank you.
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Epson inkjet printers can not prink in CMYK and must convert to RGB to render an image.
Jerry,
That is something I already know. My question is about something else altogether.
Thank you for trying, but I am still looking for my answer.
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I don't understand. You are trying to print a CMYK image on an RGB inkjet without converting it first, and then letting the printer manage the color using a profile created with an RGB target?
Can you include a screen shot of the Illustrator print settings?
Please, reread my post. You are misinterpreting it.
What I'm doing is called cross-rendering, and it's done all the time in the imaging business.
I will not allow a diversion from my topic and question, so I will ask you please to refrain from commenting if you either don't understand the question or have no way to contribute to a solution.
Thank you.
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What am I missing? Or is this a bug?
Sure sounds like a bug, considering you get the paper simulation in Photoshop from that profile.
Might need to rip the Illustrator file into PS to do this.
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Excuse me for trying to help. I am familiar with the Illustrator print settings, apparently you are not. The solution to a problem is often something simple that is overlooked.
You would get better responses if you explained your situation with a little more clarity.
Good luck with your problem.
Please, either help or spare me the hurt feelings and the platitudes.
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Excuse me for trying to help. I am familiar with the Illustrator print settings, apparently you are not. The solution to a problem is often something simple that is overlooked.
I don’t use or own Illustrator. One would hope it behaves similar to the other Adobe suite products.
He’s trying to use an output profile with the Absolute Rendering intent to simulate the paper white but it *appears* he’s just getting a Relative Rendering intent (no paper white simulation). The two intents produce the same results with the exception of the mapping of paper white and for whatever reason, perhaps an Illustrator setting (or a bug), its not honoring this rendering.
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I don’t use or own Illustrator. One would hope it behaves similar to the other Adobe suite products.
He’s trying to use an output profile with the Absolute Rendering intent to simulate the paper white but it *appears* he’s just getting a Relative Rendering intent (no paper white simulation). The two intents produce the same results with the exception of the mapping of paper white and for whatever reason, perhaps an Illustrator setting (or a bug), its not honoring this rendering.
Illustrator is not the best choice for printing a CMYK image on an inkjet because Illustrator is optimized for Postscript printing, color management is best handled in RGB.
Preserve Numbers (Ignore Linked Profiles) option is available in Illustrator for CMYK. Preserves color numbers when opening files and importing images, but still allows you to use color management to view colors accurately in Adobe applications. Select this option if you want to use a safe CMYK workflow. This option (if checked) could be the cause of the problem because it would appear correct on screen, but would not in print correctly.
In general, Illustrator is not the best choice for printing a CMYK image on an RGB device. InDesign, on the other hand gives you the option to override this color management policy.
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I don’t use or own Illustrator. One would hope it behaves similar to the other Adobe suite products.
He’s trying to use an output profile with the Absolute Rendering intent to simulate the paper white but it *appears* he’s just getting a Relative Rendering intent (no paper white simulation). The two intents produce the same results with the exception of the mapping of paper white and for whatever reason, perhaps an Illustrator setting (or a bug), its not honoring this rendering.
Well, I cannot replicate from Photoshop the same results with my file that I get in Illustrator — not with the RelCol, or Perceptual, or Saturation RI, with or without BPC.
The results produced by Illustrator with AbsCol appear to be their own kind, something apart, not related to anything comparable in Photoshop. Not a huge difference, but enough to be fairly noticeable. And no paper simulation whatsoever.
This is baffling. What the heck is going on here?
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Illustrator is not the best choice for printing a CMYK image on an inkjet because Illustrator is optimized for Postscript printing, color management is best handled in RGB.
If the application offers a choice of Absolute Colorimetric intent along with a "Let [application] determine colors" workflow, I expect it to produce results according to that intent.
Incidentally, the "Let Postscript® printer determine colors" option is grayed out in Illustrator when printing directly to an inkjet via the driver, without a dedicated RIP.
Preserve Numbers (Ignore Linked Profiles) option is available in Illustrator for CMYK.
Only when printing to a CMYK device (like a laser printer or a RIP for an inkjet). In my case (printing directly to the inkjet via the Epson driver) the "Preserve..." option is grayed out and not selectable. So, its usefulness in this case in out of the question.
In general, Illustrator is not the best choice for printing a CMYK image on an RGB device. InDesign, on the other hand gives you the option to override this color management policy.
Right now, I'm not interested in which application or workflow is best for printing or proofing a CMYK file. I know the answer to that already, and it was not what I was asking.
What interests me is that the Absolute Colorimetric intent is not producing the intended results in Illustrator, though the selectable option is there.
So, the question still remains: is this an impossibility in Illustrator? If it is, so be it. If it isn't, which workaround will make it behave properly?
By the way, I have 25 years of experience in digital workflows, and I am a veteran production specialist. I am definitely not a beginner.
Routinely, I use a RIP to print color proofs to an inkjet. This particular use of Illustrator which I describe here is highly unusual for me. All the more so, I want to get to the bottom of what I still consider a misbehavior, no matter how "advisable" or not it is to use Illustrator in this fashion.
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If the application offers a choice of Absolute Colorimetric intent along with a "Let [application] determine colors" workflow, I expect it to produce results according to that intent.
It may be something as simple as using the wrong rendering intent. If you are using absolute colorimetric, the program is only adjusting out of gamut colors. This is great for converting from a smaller color space to a larger space, but for printing, it does not take into consideration the paper color. For that you should be using Relative colorimetric which will move out of gamut colors to the closest possible color that will print on your inkjet with paper profile.
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Marco - I also think there's a bug. While printing, Illustrator seems to ignore the rendering intent selected in Print>Color Management dialog box, and it's using the rendering intent selected in Color Settings (with Advanced Mode enabled). The workaround is to set Absolute Colorimetric intent in Color Settings.
Another issue is, that the document is transparent, so if you want to have simulation of paper white, you need to put a rectangle filled with white in the background.
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It may be something as simple as using the wrong rendering intent. If you are using absolute colorimetric, the program is only adjusting out of gamut colors. This is great for converting from a smaller color space to a larger space, but for printing, it does not take into consideration the paper color. For that you should be using Relative colorimetric which will move out of gamut colors to the closest possible color that will print on your inkjet with paper profile.
I believe you've got a couple of points wrong...
* Absolute colorimetric (abscol) does not "adjust" OOG colors. It either matches them more-or-less precisely or clips them.
* Not sure exactly what you mean when you say abscol "does not take into consideration the paper color". Abscol will "impose" the paper color of the source profile on the destination profile with the result being a simulation of the source profile's paper color. This is extremely common for a proofing workflow and is the most accurate rendering of the source profile/device when printing on a different device. It's generally UNdesirable for photographic prints since you want the paper color of the source to be "mapped" or "zeroed" to the paper color of the destination.
* You say "you should be using Relative colorimetric which will move out of gamut colors to the closest possible color that will print on your inkjet with paper profile". Neither relative or absolute renderings will "move" OOG colors. They either MATCH or they CLIP. Perceptual rendering on the other hand will attempt to "scale" OOG colors from the source to the destination and in the process move other in-gamut colors "inward" in an attempt to maintain the visual separation between in-gamut and out-of-gamut colors. With relcol and abscol, you can easily end up with ink in-gamut and out-of-gamut colors that render on the print to exactly the same color (no separation or "clipped"). Main difference between relcol and abscol is that one (relcol) "zeroes" the paper white while the other imposes the paper white color of the source to the destination. Because relcol zeroes the source white point to the destination, you'll see a slightly expanded "gamut" (slightly higher chroma and lower L*) on the print depending on the initial difference between the two medias.
Hope this helps,
Terry
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It may be something as simple as using the wrong rendering intent. If you are using absolute colorimetric, the program is only adjusting out of gamut colors. This is great for converting from a smaller color space to a larger space, but for printing, it does not take into consideration the paper color. For that you should be using Relative colorimetric which will move out of gamut colors to the closest possible color that will print on your inkjet with paper profile.
As Terry said, and I will confirm and agree, your idea of gamut mapping and the role of the Absolute Colorimetric intent for paper simulation is simply incorrect (as is your ideas about Illustrator and CMYK for printing to something like an Epson). The driver is the “issue” here, not the app or the color model (GDI and Quickdraw printer drivers barf when handed CMYK data). Huge numbers of users send CMYK data to ink jets every day.
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As Terry said, and I will confirm and agree, your idea of gamut mapping and the role of the Absolute Colorimetric intent for paper simulation is simply incorrect (as is your ideas about Illustrator and CMYK for printing to something like an Epson). The driver is the “issue” here, not the app or the color model (GDI and Quickdraw printer drivers barf when handed CMYK data). Huge numbers of users send CMYK data to ink jets every day.
The point is, that no matter what rendering intent is chosen in Illustrator Print>Color Management dialog box, the print is rendered with intent, that was set in Color Settings. And if Absolute Colorimetric intent is set in Color Settings, there's a paper white simulation on the print, so just what Marco expected.
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I believe you've got a couple of points wrong...
* Absolute colorimetric (abscol) does not "adjust" OOG colors. It either matches them more-or-less precisely or clips them.
* Not sure exactly what you mean when you say abscol "does not take into consideration the paper color". Abscol will "impose" the paper color of the source profile on the destination profile with the result being a simulation of the source profile's paper color. This is extremely common for a proofing workflow and is the most accurate rendering of the source profile/device when printing on a different device. It's generally UNdesirable for photographic prints since you want the paper color of the source to be "mapped" or "zeroed" to the paper color of the destination.
* You say "you should be using Relative colorimetric which will move out of gamut colors to the closest possible color that will print on your inkjet with paper profile". Neither relative or absolute renderings will "move" OOG colors. They either MATCH or they CLIP. Perceptual rendering on the other hand will attempt to "scale" OOG colors from the source to the destination and in the process move other in-gamut colors "inward" in an attempt to maintain the visual separation between in-gamut and out-of-gamut colors. With relcol and abscol, you can easily end up with ink in-gamut and out-of-gamut colors that render on the print to exactly the same color (no separation or "clipped"). Main difference between relcol and abscol is that one (relcol) "zeroes" the paper white while the other imposes the paper white color of the source to the destination. Because relcol zeroes the source white point to the destination, you'll see a slightly expanded "gamut" (slightly higher chroma and lower L*) on the print depending on the initial difference between the two medias.
Hope this helps,
Terry
Illustrator and InDesign support a safe CMYK workflow by default. As a result, when you open or import a CMYK image with an embedded profile, the application ignores the profile and preserves the raw color numbers. If you want your application to adjust color numbers based on an embedded profile, change the CMYK color policy to Preserve Embedded Profiles in the Color Settings dialog box. You can easily restore the safe CMYK workflow by changing the CMYK color policy back to Preserve Numbers (Ignore Linked Profiles).
This is from Real World Adobe Illustrator CS3 by Mordy Golding:
Rendering Intent. If some colors in your document cannot be reproduced on the chosen output device, those colors are considered out if gamut and must be converted to colors that will reproduce on the output device. There are different methods for converting these colors, and the Rendering Intent setting determines the method used. The most commonly used method, Relative Colorimetric, moves out-of-gamut colors to the closest possible color that will print on the device. It also adjusts other colors so that colors appear to be accurate. The Absolute Colorimetric setting adjusts only out-of-gamut colors and may result in posterization, where many shades of similar colors are used. The Perceptual method shifts colors so that they appear correct relative to each other, but it may not represent colors as being the most accurate match to the original values. The Saturation method enhances colors and makes them more vibrant and most suitable for business presentations where bright colors are more important than accurate colors.
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Question for Marco:
What happens if you place, say, a box with a white file in Illustrator and send that to the printer using absolute rendering.? I would suggest assigning (but you already know this) something like SWOP Coated5 to your Illustrator document so you get a very "nasty" dark/dirty paper simulation. What I'm wondering is if you'll get a "paper" simulation over the white box but not in the surrounding "substrate" area? In other words, is abscol rendering being applied to the graphics but not to the "transparent" substrate area?
Might be interesting....unless you've already tried that.
Terry
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Question for Marco:
What happens if you place, say, a box with a white file in Illustrator and send that to the printer using absolute rendering.? I would suggest assigning (but you already know this) something like SWOP Coated5 to your Illustrator document so you get a very "nasty" dark/dirty paper simulation. What I'm wondering is if you'll get a "paper" simulation over the white box but not in the surrounding "substrate" area? In other words, is abscol rendering being applied to the graphics but not to the "transparent" substrate area?
Might be interesting....unless you've already tried that.
Terry
If you set the Absolute Colorimetric intent in Print>Color Mangement, nothing happens.
If you set the Absolute Colorimetric intent in Color Settings>Advance Mode>Conversion Options, white gets "nasty"
(XP, CS4, Epson 7880)
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This is from Real World Adobe Illustrator CS3 by Mordy Golding:
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Rendering Intent. If some colors in your document cannot be reproduced on the chosen output device, those colors are considered out if gamut and must be converted to colors that will reproduce on the output device. There are different methods for converting these colors, and the Rendering Intent setting determines the method used. The most commonly used method, Relative Colorimetric, moves out-of-gamut colors to the closest possible color that will print on the device. It also adjusts other colors so that colors appear to be accurate. The Absolute Colorimetric setting adjusts only out-of-gamut colors and may result in posterization, where many shades of similar colors are used. The Perceptual method shifts colors so that they appear correct relative to each other, but it may not represent colors as being the most accurate match to the original values. The Saturation method enhances colors and makes them more vibrant and most suitable for business presentations where bright colors are more important than accurate colors.
Mordy is wrong! The Absolute and RelCol intent is identical expect for the mapping of paper white. Its the same table! And how he can say one (RelCol) is more common than other is suspect unless he’s taken some kind of poll of which I’d like to see.
If you want your application to adjust color numbers based on an embedded profile, change the CMYK color policy to Preserve Embedded Profiles in the Color Settings dialog box. You can easily restore the safe CMYK workflow by changing the CMYK color policy back to Preserve Numbers (Ignore Linked Profiles).
That tells us nothing about how Illustrator deals with conversions FROM a color space, TO an output color space, the OP’s concern.
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If you set the Absolute Colorimetric intent in Print>Color Mangement, nothing happens.
If you set the Absolute Colorimetric intent in Color Settings>Advance Mode>Conversion Options, white gets "nasty"
(XP, CS4, Epson 7880)
Well that’s what Marco wants, “nastly” whites (paper white simulation).
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As Terry said, and I will confirm and agree, your idea of gamut mapping and the role of the Absolute Colorimetric intent for paper simulation is simply incorrect (as is your ideas about Illustrator and CMYK for printing to something like an Epson). The driver is the “issue” here, not the app or the color model (GDI and Quickdraw printer drivers barf when handed CMYK data). Huge numbers of users send CMYK data to ink jets every day.
From your previous statement you don't own or use Illustrator. Illustrator has seven pages of print set up dialog that adjusts everything from transparency flattening, printing black overlay, spot colors, preserving RGB or CMYK numbers as well as rendering intent all of which can affect print color. My experience printing with Illustrator to the Canon iPF5100 proved that conversion to RGB prior to printing gave more color accurate results while CMYK images were best handled by Postscript compatible printers.
Absolute Colorimetric does not scale colors to the destination white point. That was the only point I was trying to make. If you are testing an image on a particular paper type this intent would not be the optimal choice.
The issue here is the CMYK document going to an RGB device. Either the device or the application must make the color conversion. Illustrator and InDesign share a similar print engine in that they are both optimized for Postscript printing. If you are using a RIP this is not a problem because it does the conversions for you. Without a RIP there are several adjustments that could affect the outcome of the print. Without knowing the specifics of the OP's case, it is pointless to speculate about what went wrong.
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I don’t need to own Illustrator to point out that the text above about rendering intents is wrong.
I don’t need to own Illustrator to point out that an ICC profile using an Absolute Colorimetric intent will map identically as RelCol but with paper white simulation and that unless the OP is doing something wrong (that’s why he asked) OR there is a big fat bug in Illustrator, it don’t matter squat what the source profile assumption is, there should be a difference in output using the two options from the same profile table, with one having paper white simulation.
I don’t need to own Illustrator to tell you with no ambiguity, it doesn’t matter squat what color model a document is in, in terms of printing to an ink jet (its a driver issue, that’s WHY folks like Epson bundle a RIPs with their devices for those handling postscript and CMYK data). It has zero to do with “CMYK going to an RGB device” because the Epson isn’t an RGB device. A Lightjet is.
So far, about everything you’ve added here has been incorrect. But you say you have and use Illustrator and we hoped you could aid the OP in settings there, instead of posting nearly 100% incorrect info about color management and printing.
My experience printing with Illustrator to the Canon iPF5100 proved that conversion to RGB prior to printing gave more color accurate results while CMYK images were best handled by Postscript compatible printers.
IF you used the native GDI or Quickdraw driver from the printer, its perfectly understandable to everyone here but you as to why you experienced this. What it proved is you don’t understand the relationships between the color models, the drivers and how they interface with the printer. Your Canon is no more an “RGB printer” than the OP’s Epson. Unless Canon has now a light emitting printer called the iPF5001 exposing onto silver materials.
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The issue here is the CMYK document going to an RGB device.
The issue here is, that although Illustrator makes the color conversion, it ignores the rendering intent chosen in Print>Color Management dialog box.
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The issue here is, that although Illustrator makes the color conversion, it ignores the rendering intent chosen in Print>Color Management dialog box.
That is probably the most salient and useful comment provided to help the OP so far. Hopefully he can test this and it fixes his problem.
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Marco - I also think there's a bug. While printing, Illustrator seems to ignore the rendering intent selected in Print>Color Management dialog box, and it's using the rendering intent selected in Color Settings (with Advanced Mode enabled). The workaround is to set Absolute Colorimetric intent in Color Settings.
Another issue is, that the document is transparent, so if you want to have simulation of paper white, you need to put a rectangle filled with white in the background.
I just tried that, and there is a difference in the output, just as you suggest, crazy as that sounds otherwise.
Still, the printed colors look off, compared to what I get by printing with Photoshop – in the Illustrator print, the reds and purples are too dark, the yellows, greens and oranges more saturated.
Also, the substrate simulation is now there in the Illustrator print, amazingly so — but I had to activate the AbsCol intent in the application's Color Settings!. Still, the color of the paper simulation is wrong — in my case, too yellow-reddish, instead of the slightly bluish tinge it should have (which should match an *a value of 0 and a *b value of -1.98, to be exact [the aimpoints of GRACoL Coated v1], whereas it is *a +1.04 [too red] and *b 0 [not blue enough] in the Illustrator print).
Plotting spectral readings of the print made from Photoshop against the expected values in my destination profiles, I achieve a reasonably close match, overall (in DeltaE 2000, a max of 2.75, a min of 0.82, an average of 1.47; 60% of the values are below 1.5 DeltaE). The paper simulation measures *a -1.28 [too green] and *b -4.10 [too blue]: that is overall too blue, which probably indicates a linearity problem in the highlights in my custom profile; still the error is in the correct hue direction — blue, instead of red.
A similar plot of the spectral readings of the print made from Illustrator produces the following DeltaE 2000 values: a max of 5.89, a min of 0.94, and an average of 2.61; 43% of the values are below 1.5 DeltaE; 28% are higher than 4.5 DeltaE.
So, even when I set the RI in Illustrator's Color Settings to AbsCol, Photoshop still creates a markedly better match to my intended target.
Given all that, I would conclude that the suggested workaround, unfortunately, is not remedying the problem, though we now know that one changes the printed results in Illustrator by changing...the application's Color Settings! That is clearly a software bug, or a result of bad programming, which, in practical terms, probably amounts to the same thing.
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The point is, that no matter what rendering intent is chosen in Illustrator Print>Color Management dialog box, the print is rendered with intent, that was set in Color Settings. And if Absolute Colorimetric intent is set in Color Settings, there's a paper white simulation on the print, so just what Marco expected.
Well, as I stated and documented in my other message, it's not exactly what one would expect, as confirmed by taking colorimetric or spectral readings off the print with a spectrophotometer (in my case, an EyeOne Pro Rev B, UV-included).
True, there finally appears a paper simulation on the print, but it is the wrong hue, very different from what Photoshop produces using the very same output profile.
Also, the composite colors across the range are off as well, by significant amounts.
In other words, the problem remains: Illustrator's behavior is incorrect. In more than one way, it appears, but still incorrect in factual terms.
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Question for Marco:
What happens if you place, say, a box with a white file in Illustrator and send that to the printer using absolute rendering.?
Well... [drum roll]...nothing!
I tried that too, and it makes not a bit of difference.
I would suggest assigning (but you already know this) something like SWOP Coated5 to your Illustrator document so you get a very "nasty" dark/dirty paper simulation. What I'm wondering is if you'll get a "paper" simulation over the white box but not in the surrounding "substrate" area?
The simulated paper color that I finally get using Czornyj's workaround looks the same across the sheet, whether or not a white rectangle is placed behind the image.
In other words, is abscol rendering being applied to the graphics but not to the "transparent" substrate area?
When AbsCol is enabled in the Color Settings, the resulting paper simulation on the printout looks the same throughout the page, from what I'm able to determine.
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The issue here is, that although Illustrator makes the color conversion, it ignores the rendering intent chosen in Print>Color Management dialog box.
Exactly!
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Well, as I stated and documented in my other message, it's not exactly what one would expect, as confirmed by taking colorimetric or spectral readings off the print with a spectrophotometer (in my case, an EyeOne Pro Rev B, UV-included).
True, there finally appears a paper simulation on the print, but it is the wrong hue, very different from what Photoshop produces using the very same output profile.
Also, the composite colors across the range are off as well, by significant amounts.
In other words, the problem remains: Illustrator's behavior is incorrect. In more than one way, it appears, but still incorrect in factual terms.
I tried it myself and in my case paper simulation in Illustrator is correct - there's dE( a*b )=0,5 difference between whites from Photoshop (proof mode) and Illustrator (AbsCol), dE for primaries - C: 0.2, M: 0.3, Y: 0.2. Are you sure you assigned the same CMYK profile to the Illustrator document as you chose in Photoshop Proof Setup dialog box?
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Are you sure you assigned the same CMYK profile to the Illustrator document as you chose in Photoshop Proof Setup dialog box?
100% sure.
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100% sure.
Ciao Marco,
Interesting post. I have to run some color tests today and I'll try and recreate the issue. I actually believe that I ran into a similar issue making some tolerance charts for a customer a month or so again, I was up against a deadline so I just printed them out of PS and haven't had a chance to revisit.
Do you have a test file that you are using, that you could ZIP and send to me.
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Ciao Marco,
Interesting post. I have to run some color tests today and I'll try and recreate the issue. I actually believe that I ran into a similar issue making some tolerance charts for a customer a month or so again, I was up against a deadline so I just printed them out of PS and haven't had a chance to revisit.
Do you have a test file that you are using, that you could ZIP and send to me.
Hi Julian!
Good to see you here.
Please let me know what you come up with. I trust your sleuthing skills implicitly, and I would love to get to the bottom of this Illustrator snafu.
I'll send you my test files in a private email.
Best.