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Author Topic: More color management confusion  (Read 6279 times)

mouse

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More color management confusion
« on: August 29, 2014, 09:11:34 pm »

May I start a new thread relating to color management confusion.  I am coming at this issue as one who sends edited (and soft proofed) image files to  commercial labs for printing.   My understanding of color management is far from encyclopedic, but I believe I have sufficient grasp of the basics to recognize it when I see conflicting information.   

[In that regard, and somewhat parenthetically, I recently read a LuLa thread from 2010 (http://www.luminous-landscape.com/forum/index.php?topic=40660.0) which was rather depressing.  It does have some interesting overlap with the subjects covered in the most recent threads here on color management.  I hope that the situation described in that old thread has changed for the better.]

My confusion arises from the following statements found in the web site of a firm with an excellent reputation for quality and concern for the photographer's needs:

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"Calibrating your monitor is the first step in receiving the best monitor to print match. The second step is to embed a valid ICC profile into each file you send.  Without this profile, we do not know what colorspace your files are in. Most photographers use either sRGB or Adobe RGB (1998) as a working colorspace.

Soft-proofing with our output profiles on a properly calibrated monitor will give you the best possible screen to print match. Do not embed these profiles in your files, only use them with Photoshop's "Soft Proofing" function.
 
When you save your JPEGs out of Photoshop, make sure to check the "Embed Color Profile" checkbox in the Save dialog box. Without this checked, we do not know the color space of your files, and you will have unpredictable color in your prints."

I most frequently use my local Costco for printing.  I obtain the proper printer/paper profiles very kindly provided by Dry Creek, who also publish a very helpful tutorial on the use of the profiles for soft proofing.  The following is excerpted from their web site:

Quote
Finally, convert the image to the appropriate profile**, using your chosen rendering intent. In Photoshop CS2 and above the command is Edit→Convert to Profile. Earlier Photoshop versions use Image→Mode→Convert to Profile. Frontier and Noritsu printers do not read embedded profiles, so the image data must be converted. This changes the data in the file to compensate for how your lab's machine actually prints colors.

Do not embed the profile in the saved file. Frontier, Noritsu, and Agfa printers ignore embedded profiles, and sometimes can not process images with embedded profiles. In the File→Save As dialog box, uncheck the "Icc Profile:" box in the Color settings area.

**By "appropriate profile" I assume they mean the printer output profile.

So I sit here scratching my head. ??? ::)

I am sure the answer is NOT: "Just send them an sRGB file" as has been suggested elsewhere.
 



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digitaldog

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Re: More color management confusion
« Reply #1 on: August 29, 2014, 09:18:10 pm »

One source, the lab appears to be saying: soft proof with the profile, don't convert to the output color space with it. That's kind of pointless.
The other source (Drycreek) is telling you to use the profile and convert to the output color space. That's a lot more useful as you control the rendering intent and other parameters.
In each case the data has to have an embedded profile, both are in agreement on that.
If the lab says "send us sRGB but use the profile for soft proofing", it is a kind of half baked color management workflow. You don't know if the profile they provide for soft proof is even used for conversion, you don't know what rendering intent they use etc. In the workflow Drycreek suggests, you're in full control.
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Slobodan Blagojevic

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Re: More color management confusion
« Reply #2 on: August 29, 2014, 09:30:18 pm »

... In each case the data has to have an embedded profile, both are in agreement on that...

Are we reading the same OP?

Dry Creek:

Quote
Do not embed the profile in the saved file. Frontier, Noritsu, and Agfa printers ignore embedded profiles, and sometimes can not process images with embedded profiles.

fdisilvestro

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Re: More color management confusion
« Reply #3 on: August 29, 2014, 09:35:19 pm »

If I'm not mistaken, those two quotes from the OP are from different Labs

Lab 1:

Work your images in your preferred profile, Adobe RGB or sRGB
Use our profile for softproofing only (do not convert to it)
Remember to embed the profile used (Adobe RGB or sRGB) so we will treat it accordingly

Lab 2:
Convert your images to the provided printer profile
Do not embed the profile since it might cause issues.


I do not see confusion in those statement (unless they were from the same lab)
Now, it is important to understand that "embedding" the profile does not change the data, it is just metadata and in this particular case the second lab is requesting not to include it.

mouse

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Re: More color management confusion
« Reply #4 on: August 29, 2014, 09:41:34 pm »

If I'm not mistaken, those two quotes from the OP are from different Labs

Lab 1:

Work your images in your preferred profile, Adobe RGB or sRGB
Use our profile for softproofing only (do not convert to it)
Remember to embed the profile used (Adobe RGB or sRGB) so we will treat it accordingly

Lab 2:
Convert your images to the provided printer profile
Do not embed the profile since it might cause issues.


I do not see confusion in those statement (unless they were from the same lab)
Now, it is important to understand that "embedding" the profile does not change the data, it is just metadata and in this particular case the second lab is requesting not to include it.

Sad to say both are from the same lab, same web site, different pages.
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Slobodan Blagojevic

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Re: More color management confusion
« Reply #5 on: August 29, 2014, 09:42:59 pm »

... Now, it is important to understand that "embedding" the profile does not change the data, it is just metadata and in this particular case the second lab is requesting not to include it.

How do you work with the lab #2 out of Lightroom. You only have the option to export the file by converting it to the color space of choice. There is nothing in LR about embedding or not.

digitaldog

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Re: More color management confusion
« Reply #6 on: August 29, 2014, 09:50:40 pm »

Are we reading the same OP?
Dry Creek:
My bad, yes you are correct, they say not to embed for Frontier, Noritsu, and Agfa printers.
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fdisilvestro

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Re: More color management confusion
« Reply #7 on: August 29, 2014, 09:51:55 pm »

Sad to say both are from the same lab, same web site, different pages.

In that case, and with my experience in managing web sites, is that one of them is out dated. What I would do is to inform the lab about the contradicting information. It is a common thing to find contradictory information in different pages of a web site

digitaldog

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Re: More color management confusion
« Reply #8 on: August 29, 2014, 09:52:03 pm »

Sad to say both are from the same lab, same web site, different pages.
Well that doesn’t make any sense.
She's my mother, my sister, my mother, my sister... she's my mother and my sister... ;D
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Slobodan Blagojevic

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Re: More color management confusion
« Reply #9 on: August 29, 2014, 09:53:36 pm »

Well that doesn’t make any sense.
She's my mother, my sister, my mother, my sister... she's my mother and my sister... ;D

In Tennessee?  ;)

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Re: More color management confusion
« Reply #10 on: August 29, 2014, 09:54:18 pm »

How do you work with the lab #2 out of Lightroom. You only have the option to export the file by converting it to the color space of choice. There is nothing in LR about embedding or not.

You'd have to run the image through some other program to strip the profile.  In reality though, I doubt if there are many machines out there today that would refuse to process an image with an embedded profile.  Some of that info on the DryCreek site hasn't been updated for several years.  Pretty simple and low-cost thing to check.  Just give costco an image with a profile and see if the machine starts smoking.   ;D

It's the other scenario that always has me scratching my head.  If a machine accepts a custom profile but they DON'T want you to embed it, then how does the machine know how to process it?  If I actually sent them an image in sRGB, would it print "wrong" because it's assuming it to be in the custom color space?
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digitaldog

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Re: More color management confusion
« Reply #11 on: August 29, 2014, 09:56:34 pm »

In Tennessee?  ;)
Well in Chinatown she's my daughter and my sister  ::)
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digitaldog

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Re: More color management confusion
« Reply #12 on: August 29, 2014, 10:06:18 pm »

You'd have to run the image through some other program to strip the profile.  In reality though, I doubt if there are many machines out there today that would refuse to process an image with an embedded profile.
I believe that's correct. At least in the old days, some front ends would barf (choke) if they encountered an embedded profile. Having the data in the necessary color space, sRGB for some, is probably the key.
Quote
If a machine accepts a custom profile but they DON'T want you to embed it, then how does the machine know how to process it?
Probably like a lot of prepress CMYK workflows where the numbers just go directly to the output device, whether the profile is 'correct' or not. IOW, maybe it doesn't process it visa vie converting the data. That's just a guess.
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mouse

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Re: More color management confusion
« Reply #13 on: August 29, 2014, 11:15:51 pm »

In that case, and with my experience in managing web sites, is that one of them is out dated. What I would do is to inform the lab about the contradicting information. It is a common thing to find contradictory information in different pages of a web site

I have informed the lab.  Awaiting response.  Will report.

As for stripping the embedded profile, assuming you will convert the image to jpg, Dry Creek tells you to not check the ICC Profile box.  Don't know about LR as I don't use it.
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fdisilvestro

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Re: More color management confusion
« Reply #14 on: August 30, 2014, 12:29:23 am »

How do you work with the lab #2 out of Lightroom. You only have the option to export the file by converting it to the color space of choice. There is nothing in LR about embedding or not.



As for stripping the embedded profile, assuming you will convert the image to jpg, Dry Creek tells you to not check the ICC Profile box.  Don't know about LR as I don't use it.

That's an issue if true, since as Slobodan says, there is no user option for this in LR

D Fosse

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Re: More color management confusion
« Reply #15 on: August 30, 2014, 04:00:00 am »

This kind of thing (convert but do not embed) is quite common in the world of offset printing, the reason being that many rips (still) choke on embedded profiles. Outdated, maybe, but it happens.

That's why there is a PDF standard called PDF/X-1a that does this. It converts to destination CMYK, strips the profile, but states "output intent" to avoid confusion. This is press-ready PDF, and usually the preferred output format for InDesign files going to offset print.
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Czornyj

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Re: More color management confusion
« Reply #16 on: August 30, 2014, 04:56:18 am »

Let's start from Gary's Frontier.

It has a non-color aware controller, which by default converts anything from sRGB to emulsion profile using sort of device link profile. This conversion is of perceptual type, and it is hyper aggressive as "saturation" rendering intent (something that caused that Gary demanded from the service to straighten the bananas):
...so sending an sRGB file

...results in something like this, actually perceptual conversion uses some colours beyond sRGB, so it cannot be replicated on sRGB display, but you should get the idea:

You can simulate this behaviour by selecting the printer profile and check "Preserve RGB colours" in Photoshop soft proofing dialog box
http://products.fujifilm.eu/support/color_management/photographic/frontier_rgb.html

To counteract this aggressive rendering you can just send a target thru it, create a profile, and make a pre conversion, that will calm it down:

It doesn't matter if you embed ICC profile or not, Frontiers controller is ICC profile colour blind - it only increases the file size, so that why we may want to uncheck "embed ICC profile" while saving pre converted images.

Frontier has two working modes - sRGB (above mentioned), and PD. The second mode is more interesting from our perspective, as it is something like "ICM off" "no colour correction" known from printer drivers. It doesn't seem to proceed any limiting conversion, and allows us to utilise the whole gamut of c-print emulsion. As in sRGB mode case, we have to create/download profile created in PD mode, convert the image rendered to a large colour space, and enjoy much more saturated colours from blue-emerald-phtalogreen region, and better tonality (there's only one conversion, so there's less rounding errors). If you have a wide gamut display you can check the difference switching between sRGB and PD mode profiles:
http://products.fujifilm.eu/support/color_management/photographic/frontier_pd.html
...and here's my test file, it has a lot of out sRGB blue-turquise region colours: https://dl.dropboxusercontent.com/u/19059944/ECItest.jpg

The catch is that we have to force the printer operator to switch Frontier from sRGB to PD mode, and make sure he really did it - otherwise we'll get hyper saturated results.
« Last Edit: August 30, 2014, 05:01:49 am by Czornyj »
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Czornyj

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Re: More color management confusion
« Reply #17 on: August 30, 2014, 08:37:40 am »

Noritsu is another story. Any QSS3x0x without ("HD" symbol) behaves like Frontier in sRGB mode, and there's no PD mode  equivalent. The only way to avoid internal sRGB-centric conversion is to use Noritsu QSS Printer Driver, which also has limitations - it doesn't use sharpening, nor "RGB GCR" (which slightly limits the laser power for blacks to avoid "halo" effect), and the maximum format length is limited.

All newest Noritsu QSS with "HD" symbol - like QSS3701HD, QSS3801HD etc. at last have controller with some sort of colour management. You can define editing colour spaces that you're planning to use, and it will automatically convert the images to the ICC profile of the paper emulsion, you can also replace default profiles with custom created ones. The only limitation is it uses perceptual rendering intent by default. However it's important to check if the printer has properly configured workflow, our editing space of choice is on the controllers list, and if there's default or custom ICC profile attached.
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