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Author Topic: Absolute Colorimetric not working in Illustrator?  (Read 4824 times)
digitaldog
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« Reply #20 on: March 27, 2010, 12:13:49 PM »
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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.

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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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Andrew Rodney
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« Reply #21 on: March 27, 2010, 12:14:41 PM »
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Quote from: Czornyj
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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Andrew Rodney
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jerryrock
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« Reply #22 on: March 27, 2010, 12:32:01 PM »
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Quote from: digitaldog
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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Gerald J Skrocki
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« Reply #23 on: March 27, 2010, 12:41:23 PM »
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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.
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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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Andrew Rodney
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Czornyj
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« Reply #24 on: March 27, 2010, 12:41:34 PM »
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Quote from: jerryrock
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.
« Last Edit: March 27, 2010, 12:44:37 PM by Czornyj » Logged

digitaldog
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« Reply #25 on: March 27, 2010, 12:45:30 PM »
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Quote from: Czornyj
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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Andrew Rodney
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Marco Ugolini
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« Reply #26 on: March 27, 2010, 07:23:31 PM »
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Quote from: Czornyj
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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Marco Ugolini
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« Reply #27 on: March 27, 2010, 08:05:00 PM »
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Quote from: Czornyj
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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Marco Ugolini
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« Reply #28 on: March 27, 2010, 08:13:32 PM »
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Quote from: terrywyse
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.

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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.

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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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Marco Ugolini
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« Reply #29 on: March 27, 2010, 08:18:06 PM »
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Quote from: Czornyj
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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Marco Ugolini
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« Reply #30 on: March 28, 2010, 02:42:48 PM »
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Quote from: Marco Ugolini
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?
« Last Edit: March 28, 2010, 02:50:12 PM by Czornyj » Logged

Marco Ugolini
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« Reply #31 on: March 28, 2010, 03:12:25 PM »
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Quote from: Czornyj
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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Marco Ugolini
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« Reply #32 on: March 30, 2010, 01:40:21 PM »
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Quote from: Marco Ugolini
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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Julian Mussi

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« Reply #33 on: March 30, 2010, 01:48:39 PM »
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Quote from: Mussi_Spectraflow
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.
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Marco Ugolini
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