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TomG
02-01-2010, 01:41 AM
On the Fiery customer CDs there's a document called FieryColorRef.pdf (http://download.support.xerox.com/pub/docs/XRIP_700DCP_Base/userdocs/any-os/en/FieryColorRef.pdf) that describes a recommended workflow for printing better colors and quality. Some advices I didn't fully understand and others were inconsistent in my eyes. It would be nice to get answers for less confusing... Here are my questions:


Pages 20, 21: It's said that Office applications (e.g. Microsoft Word) uses RGB and this why converts all non-RGB objects to RGB. The only way to keep CMYK or spot colors is to use EPS files.

- Is this really true?
- How does Word convert? (Rendering Intent? Source color profile?)
Also, if you place several RGB images that need different Rendering Intents, you shall convert the photographic objects into CMYK with Adobe Photoshop and then place them as EPS in Word (see also page 25).

- This just means you convert these objects manually, right?
- Does this mean Fiery's Rendering Intent works only with RGB images?
- How are CMYK objects converted then? There must also be a Rendering Intent.

Page 22: Generally it's said that there's a difference between No color management, PostScript color management, Printer color management and application color management, e.g. when printing from Adobe applications. Also, you shouldn't include PostScript color management information but ICC color information when saving to EPS (see also page 27).

- What are the differences between these:
- I think No color management means in the PostScript data stream there's only "anonymous" RGB, CMYK and spot information without any color space definitions. So Fiery enforces the source ICC color profiles and Rendering Intent as defined in the driver or in the color setup. Right?
- I dont's understand PostScript color management and Printer color management because Adobe applications use both terms simultaneously. In Adobe you can select the item PostScript-/Printer color management from the dropdown menu.
- I always understood Adobe's PostScript-/Printer color management as the fact that Adobe sends the original color information to the printer driver and lets the driver do color conversion. FieryColorRef.pdf says that No color management does this. Now I have problems between these settings' behavior, especially what is meant with PostScript-/Printer color management.

Page 25: It's said that Fiery uses the embedded ICC-profiles for RGB objects instead of the Fiery RGB settings.

- Does this mean that Fiery always prefers embedded ICC object information such as source color profile and also output intent (Rendering Intent)? For RGB and CMYK objects?
Page 29: It's recommended to embed ICC profiles, e.g. Fiery RGB or EFIRGB.

- These RGB profiles are not standardized as Adobe RGB, sRGB or ECI RGB. What makes them special or better to print with a Fiery controller?
- Usually when you don't create the files to be printed, e.g. as a print provider or copy shop, wouldn't it be better to recommend a standardized RGB color space as the application's default color working space? Same question as before: what would be worse?
Pages 31, 32: Now the most confusing of all: "When saving a document, you have the option to embed a color profile in the document. If you will send the document to the Color Server, we recommend that you disable this option."

- Why that? Before it was said that you sould always embed ICC color profile information. If you don't embed it then the color space information gets lost for future applications, right?
I have learned that PostScript generally cannot contain color space information, so all objects (vector graphics, text and raster images) are saved as "anonymous" RGB, CMYK or spot color objects without color space definitions. The big difference is when you import (good) PDF files into the Fiery controller via CWS or Hot Folders that all color space definitions are preserved. So printing over the printer driver always causes less color control and this why can produce less color quality. But I also learned that PostScript Level 3 has improved somehow but I don't know in which way.

- Can PostScript preserve ICC profiles for the document color space as well as for every object color space?

kmuser
02-02-2010, 07:52 AM
Hi!

I will try to shortly and quickly answer your questions based on my actual knowledge and understanding.

1) It's true (if using PS driver)
Word convert from embedded profile to sRGB using perceptual intent.
(sRGB is the default working space in Windows and can't be changed)

2) No color management = postscript file is created with the original % from the document and no other color information
PS color management = as above, but CSA and CRD are included
(this are the equivalents of ICC color profiles in PS)
Printer color management = as PS color management and no CRD
(you are right, PS and Printer color management are very similar)
Appl. color management = % in the postscript are modified for "direct" printing (in Fiery, RGB and CMYK source profiles="none").These % are different then the ones in the document.

3) Fiery will honor the embeded profiles in the document (if any).
Not true for the rendering intent.

PostScript doesn't contains embeded color profiles(only PDF,tiff etc - so, for use embedded profiles, you should import them, not print).
Further more, in a PDF one can attach a different color profile to any object in the file. Fiery will not detect all of them.
Normally, as standard, in a PDF file should be no more than one RGB color
profile and one CMYK.

4) It's a good idea to work with standard profiles (this is the correct way to produce documents for portability).Many times, we don't know/care on what kind of eq. will print.
On the other hand, there are some considerations:
- avoid standard large gamut RGB profiles (widegamutRGB.icc etc)
The more the bigger the gamut is, the more chances of "blue turns purple" and even "red turns orange" effect.This is due to the perceptual unevenness of Lab color space and the fact that color transformation is always done preserving a constant hue in Lab.
- some "not standard" profiles are generated with this effect in mind and can deal with it (EFIRGB, Fiery RGB). sRGB, AdobeRGB,AppleRGB etc. don't take it into account.
- more important is that you use the same profile(s) as working spaces for appl. and as source profiles in Fiery.

5) No embeded profile = No color management => unpredictable colors
(extreme example: You can take AdobeRGB and switch color channels => AdobeBRG. Use it as color space in Photoshop and draw a strawberry and adjust the color.Save it without embedding color profile.Open it with other appl. and see/print it. => the strawberry will be blue)
I think that in the book is about importing it in ColorServer (as tiff) and not printing it from another appl.Anyway, if you use the same profile(s) as working spaces for appl. and as source profiles in Fiery, doesn't matter embedding or not.

6) ICC profiles cannot be included in any version of postscript.
That's why we should make a manual selection for source color profiles in Fiery and there is no "Auto" option.
Even so, in postscript color info can be preserved by mean of use of:
- CSA=color space array ("equivalent" of ICC source profile)
- CRD=color rendering dictionary (equiv. of dest profile)
In PS, as standard, only one CSA and one CRD can be used.

TomG
02-02-2010, 02:18 PM
Thanks for your good reply! Still some questions:


1) It's true (if using PS driver)

Why only "if using PS driver"? Does Word's color conversion rely on the selected driver?


Word convert from embedded profile to sRGB using perceptual intent.

New to me.


(sRGB is the default working space in Windows and can't be changed)

The same as I know.


2) No color management = postscript file is created with the original % from the document and no other color information

The same as I know.


PS color management = as above, but CSA and CRD are included
(this are the equivalents of ICC color profiles in PS)

New to me.


Printer color management = as PS color management and no CRD
(you are right, PS and Printer color management are very similar)

I also read: when you select this type in Photoshop, it shows an information that says this activates the color management in the operating system's printer driver.


Appl. color management = % in the postscript are modified for "direct" printing (in Fiery, RGB and CMYK source profiles="none").These % are different then the ones in the document.

The same as I know. I also tried and in some cases the result is really better than Fiery's CMS (image looks smoother and brighter, no bandings etc.), even when you directly import a PDF by Command WorkStation or Hot Folder.


3) Fiery will honor the embeded profiles in the document (if any).
Not true for the rendering intent.

How much does Fiery "honor" them? Or in other words: what not? Do we talk about PDF's ICC profiles or PostScript's equivalents?


PostScript doesn't contains embeded color profiles(only PDF,tiff etc - so, for use embedded profiles, you should import them, not print).

You mean import by Command WorkStation or Hot Folder and not print by the PostScript printer driver, do you? We always prefer this way.


Further more, in a PDF one can attach a different color profile to any object in the file. Fiery will not detect all of them.

I knew that, but I didn't know that Fiery cannot detect all of them? Which not?


Normally, as standard, in a PDF file should be no more than one RGB color
profile and one CMYK.

You can never guarantee. What happens if there are more than one embedded ICC profile for RGB and CMYK? Does Fiery look for the first one and ignores all the others for the same color space?


4) It's a good idea to work with standard profiles (this is the correct way to produce documents for portability).Many times, we don't know/care on what kind of eq. will print.
On the other hand, there are some considerations:
- avoid standard large gamut RGB profiles (widegamutRGB.icc etc)
The more the bigger the gamut is, the more chances of "blue turns purple" and even "red turns orange" effect.This is due to the perceptual unevenness of Lab color space and the fact that color transformation is always done preserving a constant hue in Lab.
- some "not standard" profiles are generated with this effect in mind and can deal with it (EFIRGB, Fiery RGB). sRGB, AdobeRGB,AppleRGB etc. don't take it into account.

That means EFIRGB and Fiery RGB describe smaller gamut, optimized for the RGB colors that can be converted in a good way? What's the difference between EFIRGB and Fiery RGB?


- more important is that you use the same profile(s) as working spaces for appl. and as source profiles in Fiery.

In reality this is not always possible because you never know what files you get and maybe you don't have the same source profile. That's why I'd like to hear that Fiery detects and prefers embedded ICC profiles. But as you said this is not fully supported, is it?


5) No embeded profile = No color management => unpredictable colors
(extreme example: You can take AdobeRGB and switch color channels => AdobeBRG. Use it as color space in Photoshop and draw a strawberry and adjust the color.Save it without embedding color profile.Open it with other appl. and see/print it. => the strawberry will be blue)
I think that in the book is about importing it in ColorServer (as tiff) and not printing it from another appl.Anyway, if you use the same profile(s) as working spaces for appl. and as source profiles in Fiery, doesn't matter embedding or not.

Last sentence: right and clear. But even if you import a TIFF-image into CWS and you don't have an embedded ICC profile, the Fiery cannot auto-select the right source RGB profile. Isn't this stupid?


6) ICC profiles cannot be included in any version of postscript.
That's why we should make a manual selection for source color profiles in Fiery and there is no "Auto" option.
Even so, in postscript color info can be preserved by mean of use of:
- CSA=color space array ("equivalent" of ICC source profile)
- CRD=color rendering dictionary (equiv. of dest profile)
In PS, as standard, only one CSA and one CRD can be used.
Are PDF ICC profiles converted automatically to CSA/CRD when you print the PDF with the PostScript printer and if yes, how? What happens if the PDF has more than one RGB and CMYK?

kmuser
02-03-2010, 01:17 AM
Hi, again!

Here are some additional infos about your questions:

- "It's true (if using PS driver)" <- because I was in a hurry, here is a little mistake: Word will convert everything to RGB except EPS, but, if you print it to a "native" PCL device (=RGB printer for apps. & OS), all data will be converter to RGB. (native PS printers accept as input both RGB & CMYK data)

- "Word convert from embedded profile to sRGB using perceptual intent."
Indeed, Word can handle color profiles -> save in Photoshop the same picture twice with 2 different color profiles (ex: CIERGB and ProPhotoRGB) and import them in Word.Further more, you can use Photoshop to check if the rendering intent is perceptual or not.)
You can make an image opened in, for example, Photoshop, Corel and Word should look almost the same (99.9%) with the right color management settings (it is normal to have a difference between because of the CMM used:
Word can use only MicrosoftCMM - this one is the worse, so in Adobe I use AdobeCMM, Corel - KodakCMM)

- "Printer color management = as PS color management and no CRD"
"I also read: when you select this type in Photoshop, it shows an information that says this activates the color management in the operating system's printer driver."
From my point of view, this is not true. Color management in OS's printer driver is activated by the presence of a color profile in the "Color management" tab of driver's properties.

- "Fiery will honor the embeded profiles in the document (if any)."
"How much does Fiery "honor" them?"
Fiery will honor embeded profiles only for files imported through CWS (PDF, tiff etc)
For PS files, Fiery will not check for any CSA included.

- "You mean import by Command WorkStation or Hot Folder and not print by the PostScript printer driver, do you?" - a big YES

- "I knew that, but I didn't know that Fiery cannot detect all of them? Which not?"
Because the normal way to create docs is to have only one RGB and/or CMYK embeded profile.Why having a different profile for every object in the job? -> This is like many printer/platesetters manufacturers do as an advertising: Our device can print the hole Bible on a A3 page! <= so what? When I will have a job like that?

Also, take into account the rise of the processing power/time needed to check and convert(color manage) every object in the job!

- "You can never guarantee. What happens if there are more than one embedded ICC profile for RGB and CMYK? Does Fiery look for the first one and ignores all the others for the same color space?"
Fiery will look for the first one.
It's true, can never guarantee.I can make a very small doc (in size) that will bust any controller on earth.
That's why some rules should be defined.

- "That means EFIRGB and Fiery RGB describe smaller gamut, optimized for the RGB colors that can be converted in a good way? What's the difference between EFIRGB and Fiery RGB?"
What I mean is that EFIRGB & FieryRGB are optimized for the "blue turns purple" effect.In fact, both of them are similar as gamut with sRGB.

- "In reality this is not always possible because you never know what files you get and maybe you don't have the same source profile. That's why I'd like to hear that Fiery detects and prefers embedded ICC profiles. But as you said this is not fully supported, is it?"
I was meaning your apps. color working space, not the embedded profiles from the customer docs. The jobs from your customers can have any profiles, as long are embedded.

- "Last sentence: right and clear. But even if you import a TIFF-image into CWS and you don't have an embedded ICC profile, the Fiery cannot auto-select the right source RGB profile. Isn't this stupid?"

If the tiff doesn't have an embedded profile, Fiery will use the settings choosen by you with CWS:
- RGB Tiff no profile -> will asume the profile set in RGB source
- CMYK Tiff no profile -> will use the one set as CMYK simulation(source)

- "Are PDF ICC profiles converted automatically to CSA/CRD when you print the PDF with the PostScript printer and if yes, how? What happens if the PDF has more than one RGB and CMYK?"
Print PDF with PostScript printer - I assume you mean PS driver.In this case,if CSA/CRD are used in resulting PS file depends of your application printing settings.(see question no. 2)

TomG
02-03-2010, 02:32 AM
Thanks a lot, your knowledge is really refreshing! Still some (hopefully last) annotations and questions:


Hi, again!

Here are some additional infos about your questions:

- "It's true (if using PS driver)" <- because I was in a hurry, here is a little mistake: Word will convert everything to RGB except EPS, but, if you print it to a "native" PCL device (=RGB printer for apps. & OS), all data will be converter to RGB.

So PCL contains RGB only? That is new to me. But this would explain why Fiery's PCL driver has no extended ColorWise options.


(native PS printers accept as input both RGB & CMYK data)

Yes, I agree.


- "Word convert from embedded profile to sRGB using perceptual intent."
Indeed, Word can handle color profiles -> save in Photoshop the same picture twice with 2 different color profiles (ex: CIERGB and ProPhotoRGB) and import them in Word.Further more, you can use Photoshop to check if the rendering intent is perceptual or not.)

What does Word use in case there's no embedded profile?


You can make an image opened in, for example, Photoshop, Corel and Word should look almost the same (99.9%) with the right color management settings (it is normal to have a difference between because of the CMM used:
Word can use only MicrosoftCMM - this one is the worse, so in Adobe I use AdobeCMM, Corel - KodakCMM)

Yes, I agree.


- "Printer color management = as PS color management and no CRD"
"I also read: when you select this type in Photoshop, it shows an information that says this activates the color management in the operating system's printer driver."
From my point of view, this is not true. Color management in OS's printer driver is activated by the presence of a color profile in the "Color management" tab of driver's properties.

Partially right, just have a look in Photoshops note when you select Printer color management. So this option should exactly be the same as No color management if there's no color profile present in the OS's printer driver's color management tab. Would you agree?


- "Fiery will honor the embeded profiles in the document (if any)."
"How much does Fiery "honor" them?"
Fiery will honor embeded profiles only for files imported through CWS (PDF, tiff etc)
For PS files, Fiery will not check for any CSA included.

This means embedded ICC profiles are honored in single image import, not for PDF and even not for PostScript (printer driver)?


- "You mean import by Command WorkStation or Hot Folder and not print by the PostScript printer driver, do you?" - a big YES

- "I knew that, but I didn't know that Fiery cannot detect all of them? Which not?"
Because the normal way to create docs is to have only one RGB and/or CMYK embeded profile.Why having a different profile for every object in the job?

Easy answer: Last year I've been on trainings from ICC and FOGRA where the advantages of PDF/X-3 and X-4 have been explained to print providers. The key word was "media neutral producing" -> means DON'T convert images, always embed the originals in PDF including their ICC profiles. You never know if the document shall be printed or viewed on screen... This ensures best quality for all kinds of output.

It makes no sense to manually convert an ECIRGB image to CMYK using ISO Coated v2 (FOGRA39) when you don't know if your press or digital printer has a different gamut to ISO Coated v2. It's always necessary to re-convert the image to the gamut of the output-device... so you cannot prevent to convert twice what means loss of quality. It's always better to convert the original to the output-device. Would you agree?

In these times you don't know where your images come from. That's why it happens that you get ECIRGB as well as sRGB images for the same job.


-> This is like many printer/platesetters manufacturers do as an advertising: Our device can print the hole Bible on a A3 page! <= so what? When I will have a job like that?

By the way: Xerox production printers can do that with Specialty Imaging MicroText.


Also, take into account the rise of the processing power/time needed to check and convert(color manage) every object in the job!

- "You can never guarantee. What happens if there are more than one embedded ICC profile for RGB and CMYK? Does Fiery look for the first one and ignores all the others for the same color space?"
Fiery will look for the first one.
It's true, can never guarantee.I can make a very small doc (in size) that will bust any controller on earth.
That's why some rules should be defined.

Good to know!


- "That means EFIRGB and Fiery RGB describe smaller gamut, optimized for the RGB colors that can be converted in a good way? What's the difference between EFIRGB and Fiery RGB?"
What I mean is that EFIRGB & FieryRGB are optimized for the "blue turns purple" effect.In fact, both of them are similar as gamut with sRGB.

Sorry, this is not clear to me. In my opinion the conversion engine should prevent these "blue turns purple" things, not the source profile if the gamut is nearly the same as e.g. sRGB.


- "In reality this is not always possible because you never know what files you get and maybe you don't have the same source profile. That's why I'd like to hear that Fiery detects and prefers embedded ICC profiles. But as you said this is not fully supported, is it?"
I was meaning your apps. color working space, not the embedded profiles from the customer docs. The jobs from your customers can have any profiles, as long are embedded.

If I understood right, this means: The color working color spaces for RGB and CMYK in e.g. Adobe InDesign are sent to the PS printer driver (maybe it converts them to CSA/CRD but Fiery ignores them anyway -> so it's a must to select the right source profiles in ColorWise to get predictable results) and are also embedded in a PDF. If using PDF, Fiery ignores the object-specific ICC-profiles but honors the document's color spaces (= InDesigns working color space) -> Fiery then uses these color profiles for every RGB and CMYK object even if the object-specific ICC-profile is different. Right?


- "Last sentence: right and clear. But even if you import a TIFF-image into CWS and you don't have an embedded ICC profile, the Fiery cannot auto-select the right source RGB profile. Isn't this stupid?"

If the tiff doesn't have an embedded profile, Fiery will use the settings choosen by you with CWS:
- RGB Tiff no profile -> will asume the profile set in RGB source
- CMYK Tiff no profile -> will use the one set as CMYK simulation(source)

Clear. And if there's an embedded ICC-profile in the TIFF image, Fiery will use the embedded profile, right?


- "Are PDF ICC profiles converted automatically to CSA/CRD when you print the PDF with the PostScript printer and if yes, how? What happens if the PDF has more than one RGB and CMYK?"
Print PDF with PostScript printer - I assume you mean PS driver.In this case,if CSA/CRD are used in resulting PS file depends of your application printing settings.(see question no. 2)
New to me. How do I know if CSA/CRD is created? I mean as long as Fiery ignores them anyway, this is not really important...

Do you know if CSA/CRD has the same features and quality or is this completely different to embedded ICC-profiles in PDF?

Again, thanks a lot!!!

kmuser
02-04-2010, 07:48 AM
Thanks for you kind words.
I found some spare-time, so I managed to reply you.

- "So PCL contains RGB only? That is new to me. But this would explain why Fiery's PCL driver has no extended ColorWise options."

A "native" PCL device will accept as input only RGB data. That's why those devices, from appl. & OS point of view, are "RGB printers".
Anyway, Fiery, when place as frontend of an engine, is PS "native".

- "What does Word use in case there's no embedded profile?"
Word will assume then sRGB (assign profile)

- "Partially right, just have a look in Photoshops note when you select Printer color management. So this option should exactly be the same as No color management if there's no color profile present in the OS's printer driver's color management tab. Would you agree?"
You can try both options with a Fiery controller and check if the results are different.
On a CREO one, there is a difference, but this forum is for EFI products.

- "This means embedded ICC profiles are honored in single image import, not for PDF and even not for PostScript (printer driver)?"
Honor for imported jobs = for PDF, TIFF
NOT for PS files (no CSA check)

- "Easy answer: Last year I've been on trainings from ICC and FOGRA where the advantages of PDF/X-3 and X-4 have been explained to print providers. The key word was "media neutral producing" -> means DON'T convert images, always embed the originals in PDF including their ICC profiles. You never know if the document shall be printed or viewed on screen... This ensures best quality for all kinds of output."

This is true, if:
- you will print in a photo minilab
- watch the docs on screen

If none of the above:
- digital printing is always compared with offset (customers do it!)
- offset printing have standards (digital - no):
-> now is ISO (coated/uncoated)
-> before was: Euroscale for Europe/SouthAmerica
SWOP for NorthAmerica/Canada
Toyo (Japan)

In our business, if the doc is viewed on screen or printed should make no difference.This is softproofing. I'm not interested in colors that an offset machine cannot reproduce.

- "It makes no sense to manually convert an ECIRGB image to CMYK using ISO Coated v2 (FOGRA39) when you don't know if your press or digital printer has a different gamut to ISO Coated v2. It's always necessary to re-convert the image to the gamut of the output-device... so you cannot prevent to convert twice what means loss of quality. It's always better to convert the original to the output-device. Would you agree?"

Again, ISO is a standard. I agree, it is not necessary to convert a RGB image to CMYK, but, if I have to, I will choose ISO v2.
If I get 2 images with 2 different profiles to be layed-down in a doc, I will convert them to a common one.
Converting twice will not render too much quality loss.

- "Sorry, this is not clear to me. In my opinion the conversion engine should prevent these "blue turns purple" things, not the source profile if the gamut is nearly the same as e.g. sRGB."

When creating color profiles, we print % and measure color (Lab, for instance).So, for a complete RGB profile, we will need to print and measure 256x256x256=16777216 patches. In practice, we measure a few houndreds or thousands of patches.
Here came the CMM to approximate for colors/% that we didn't measure, to make the conversions based on the rendering intent, to compensate for the white point or black one.
No matter the rendering intent, one rule is kept for this conversion: constant hue. The problem is that in Lab/XYZ a constant hue line will not offer visual constant hue.

- "If I understood right, this means: The color working color spaces for RGB and CMYK in e.g. Adobe InDesign are sent to the PS printer driver (maybe it converts them to CSA/CRD but Fiery ignores them anyway -> so it's a must to select the right source profiles in ColorWise to get predictable results) and are also embedded in a PDF."

Working color spaces, in conjunction with your display profile, are used for softproofing = to show you (more or less) the real colors of your doc.
When creating a PDF file you can choose to embedd or not color profile(s).

- "And if there's an embedded ICC-profile in the TIFF image, Fiery will use the embedded profile, right?"

Yes.

- "Do you know if CSA/CRD has the same features and quality or is this completely different to embedded ICC-profiles in PDF?"

CSA/CRD mechanism is similar in results with ICC profiles.(tables and rendering intent are included).However, a ICC profile include much more information(ever pre- and post-linearisation data, type of media used etc.).

I hope I could answer to your questions.

TomG
02-04-2010, 08:22 AM
Close to the end... :rolleyes:


- "Partially right, just have a look in Photoshops note when you select Printer color management. So this option should exactly be the same as No color management if there's no color profile present in the OS's printer driver's color management tab. Would you agree?"
You can try both options with a Fiery controller and check if the results are different.

I will check this.


In our business, if the doc is viewed on screen or printed should make no difference.This is softproofing. I'm not interested in colors that an offset machine cannot reproduce.

Again, ISO is a standard. I agree, it is not necessary to convert a RGB image to CMYK, but, if I have to, I will choose ISO v2.
If I get 2 images with 2 different profiles to be layed-down in a doc, I will convert them to a common one.
Converting twice will not render too much quality loss.

I agree, but usually we aren't the designers. I think best would be to let Fiery convert correctly by taking care of object-specific embedded ICC profiles. But as you said this would increase RIP time.


Working color spaces, in conjunction with your display profile, are used for softproofing = to show you (more or less) the real colors of your doc.
When creating a PDF file you can choose to embedd or not color profile(s).

Important detail: Fiery will automatically use embedded color profiles as RGB and CMYK source color profile in PDF -- no matter what is set in ColorWise as source profiles -- Right? Or do you have to specify "No" in ColorWise RGB source/CMYK simulation settings -- otherwise these settings will overwrite the embedded color profiles?

If there are no embedded ICC-profiles, Fiery will definitely use the specified profiles in ColorWise, that's clear. But what does Fiery use as source profile if you specify "No" for RGB source/CMYK simulation settings and there're no embedded profiles?

kmuser
02-05-2010, 02:08 AM
Important detail: Fiery will automatically use embedded color profiles as RGB and CMYK source color profile in PDF -- no matter what is set in ColorWise as source profiles -- Right? Or do you have to specify "No" in ColorWise RGB source/CMYK simulation settings -- otherwise these settings will overwrite the embedded color profiles?

If there are no embedded ICC-profiles, Fiery will definitely use the specified profiles in ColorWise, that's clear. But what does Fiery use as source profile if you specify "No" for RGB source/CMYK simulation settings and there're no embedded profiles?

Fiery will automatically use embedded color profiles as RGB and CMYK source color profile in PDF -- no matter what is set in ColorWise as source profiles.
=>True.

If you specify "No" for RGB source/CMYK simulation settings and there're no embedded profiles, % from the docs are passed without any alteration to the print engine.
But here is a little catch! CMYK % can be passed directly to output, but what about RGB %? EFI doesn't specify that. What I mean is, even if you select "none" for RGB, somehow a "color profile" should be used for RGB->CMYK transform.
It's easy if we have to transform from RGB to CMY, but we have also to generate the K channel (we all know how important is this K channel in the final print!).
Other manufacturers don't provide this "odd" option for RGB source profile - "none".