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Input/Output/Workflow Scanning, printing, color management, and discussing best practices for control and repeatability

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  #1  
Old 06-09-2004, 03:41 AM
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ljl269 ljl269 is offline
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imbedded profile

My congrats to all involved for a well designed site with great content. Any site that yields relevent info in < 5 mins I join!

Attached r 2 GretagMacbethColorChecker where 1 has an imbedded profile. These look a bit different to me no matter what I enable in Ulead's PI8 Color Management.

1-Is the idea that the image with the imbedded profile will display accurately on any calibrated monitor & print accurately on any printer that recognizes imbedded profiles? Here accurately means matches to the eye the purchased GretagMacbethColorChecker.

2-What profiles r embedded? I thought it would be monitor but 1 site said it's capture device.

BTW Color Management is about the most difficult subject associated with a PC 4 me.

Your help is MUCH appreciated. Any Comments/ suggestions/corrections appreciated.Thanks- bye- Larry
Attached Images
File Type: jpg ColorChecker-ImbedsRGB+Gamma=2.2.jpg (16.1 KB, 8 views)
File Type: jpg ColorCheckerChart.JPG (24.6 KB, 8 views)
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  #2  
Old 06-09-2004, 06:06 AM
Vikki Vikki is offline
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I'm not sure what you're asking.
If you want to compare images with and without profiles, you would use the same image.

Maybe this will help (not to be considered an expert at this though) Think of embedded profiles as a "code" that tells a device how to render colors.

As an analogy, think of a profile as a box of crayons.
My camera uses sRGB crayons and colors reds using the red2 crayon.
However, my monitor uses an aRGB box of crayons. It has a few crayons that look red, but doesn't have the red2 crayon. So, the monitor will make a substitution, and use a medium red crayon.

To make it even crazier, my printer uses Epson crayons, and doesn't have either of the red crayons used by my sRGB crayons (camera) or aRGB crayons (monitor). It only has a redx crayon.

Now, when I see the image on my monitor, the reds may not look like the actual color I saw when I took the picture, because it's not able to produce the same red color. When I go to print the image, it doesn't look like the image on my screen because the printer doesn't have the same exact red used by my monitor.

Embedded profiles tells the device which crayons were used to for the image. Soft profiling allows you to "preview" how the image will look when "colored" using different "crayons" .

Bottom line: When you have an image from your camera or scanner, if it has a profile, your program will know which box of crayons was used, so that it can render the image as accurately as possible, using the box of crayons it has. You can then tell the program to "convert" the profile to your printer's profile, so that it knows how to convert the colors using the crayons your printer has available.
Does that make sense?
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  #3  
Old 06-09-2004, 11:50 AM
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Chip Hildreth Chip Hildreth is offline
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Vikki, that was without a doubt the best plain english description of basic color management I have ever seen.

I can only add, and my plain english will not be so good, that profiles go with devices like monitors, printers, cameras, etc. The profile that probably matters most is the printer, or more specifically, the printer/paper combination. Say your working with the epson crayons and you print on a piece of plain old bond paper and then you print on a piece of very expensive, glossy epson paper... the color checker will look different on each print. The printer software needs to know what kind of paper you're using so it can adjust how much of each crayon to use to get as close to the expected color as possible.

Color management and profiling are a big ball of wax that is hard to get you brain around, at least for a while. But once you start to get it figured out with your particular system, it will be a simple set of steps to take each time to make sure everything (all your devices, paper and inks) is in harmony and reading from the same page. From a printing perspective, you can look into Harald Johnson's book, 'Mastering Digital Printing'. He also has a helpful website, 'www.dpandi.com'.

Lastly, beware, this is a subject involving many possible solutions to a single set of problems and opinions are many... and often strongly stated as though they were gospel. You have to work out your own methods. You'll know they are right when the results are good, as expected, and repeatable.
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Old 06-09-2004, 04:21 PM
Vikki Vikki is offline
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Thanks Chip, but I can't take full credit for that analogy.
Gary Box was my inspiration. I read this quite a while ago, and upon reading it again just now, I think in my interpretation I've clumped "color profiles" and ""color spaces" into one.
Even so, putting it in these terms has helped me comprehend these issues, and I wanted to pass it on, as I know so many people are struggling with this.
Good point to mention the paper profiles.
To read Gary's article:
Click on: Understanding Colorspace
Also read: Device Profiles (link on his site)
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Old 06-10-2004, 12:24 AM
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ljl269 ljl269 is offline
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Thank you for such a quick response.

RE:'I think in my interpretation I've clumped "color profiles" and ""color spaces" into one"- I was gonna suggest color spaces = brand of crayon(or paints).

Comments/suggestions/corrections appreciated.
Thanks- bye- Larry
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  #6  
Old 06-10-2004, 12:50 AM
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ljl269 ljl269 is offline
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Good Pt

QUOTE=Chip Hildreth] Lastly, beware, this is a subject involving many possible solutions to a single set of problems and opinions are many... and often strongly stated as though they were gospel. You have to work out your own methods. You'll know they are right when the results are good, as expected, and repeatable.[/QUOTE]

This is atually a subproblem that arose from calibrating my monitor which, without extra hardware, has many solutions (like 2 equations with 3 unknowns). I have at least 3 that will pass 'gray pattern tests' at 3 sites but fail some real-world tests(from which this question arose). I think ur advise above is applicable to monitor calibration.

From experimenting I'm trying to get a list of tests & general guidelines. IE: in nVidia driver, Gamma correctionms > 10% probably dont work very well outside of 'gray pattern tests' !

That will be subject of a later post so I dont want to say 2 much. Thanks- bye- Larry
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  #7  
Old 06-10-2004, 03:21 PM
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Chip Hildreth Chip Hildreth is offline
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My work involves mostly paper and ink so my perspective is very print oriented. I use Adobe Gamma to adjust my monitor for changes in lighting conditions and I use soft proofing in Photoshop as a rough guide. Otherwise, I'm pretty ignorant about color management for monitors.
I thought I should at least try and address your original questions with what I've learned so far. Expect dissenting opinions and corrections from others. I'm certain to miss things or be mis-understood... but it's a start in the right direction.

Quote:
Originally Posted by ljl269
1-Is the idea that the image with the imbedded profile will display accurately on any calibrated monitor & print accurately on any printer that recognizes imbedded profiles? Here accurately means matches to the eye the purchased GretagMacbethColorChecker.

The embedded profile is a color key specific to a device like a camera, monitor, scanner or printer and it's used in conjunction with a reference model to render colors as accurately as possible on a different device with different color capabilitiy. Everything has to be coordinated in terms of the reference model, how the file is to be used and at what point the profiles are applied. It is very likely the colors will not match between different devices and the original because light and color work differently on monitors and paper and, practically all devices have different capabilities when it comes to rendering color..

2-What profiles r embedded? I thought it would be monitor but 1 site said it's capture device

Originally, it's the capture device, usually camera or scanner, but it can be converted to any other device profile and saved that way. The capture device profile is a description of what colors the device can record and what values it assigns to those colors (device charaterization). It's what set of crayons the device uses. sRGB is the general purpose profile for PC monitors running windows and is almost a standard for digital cameras and scanners. It's the safest profile for display applications and it prints most images well too.

BTW Color Management is about the most difficult subject associated with a PC 4 me.

Like I said earlier, it's difficult at first but you can get the hang of it by being methodical. As you work with it, you will make happy mistakes that work perfectly. Research those mistakes to figure out what went right and learn to repeat them. Then, it's easy to find information and opinions backing up what you did. When I was first trying to use color management to print, I wasted $140 worth of fine art paper trying to match a painting. About two thirds of the way through, I got a match but couldn't repeat it. Turned out I was applying the same profile twice and that one match happened when I forgot to tell the printer to apply the profile. I later learned that double profiling was a common issue.
These days, I have a standard workflow for printing to the printers for which I have profiles and most of it is safely recorded in Photoshop actions so I don't screw up.
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  #8  
Old 06-10-2004, 07:28 PM
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"These days, I have a standard workflow for printing to the printers for which I have profiles and most of it is safely recorded in Photoshop actions so I don't screw up."

This idea seems pretty tasty. Could you supply details of your workflow as a rough guide to others?

Cheers
Dave
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  #9  
Old 06-10-2004, 08:59 PM
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Chip Hildreth Chip Hildreth is offline
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Dave,
I'm happy to pass this on though you should take it with a big grain of salt. I'm not formally trained, this is just what I've figured out over time that happens to work for me with my equipment and software... which I should probably outline first.
I shoot either a Nikon D1X recording RAW files or film (6x7 or 4x5) and scan using an Imacon FT848 ccd scanner.
For the Nikon, I process the RAW files into TIFFs using Phase One's CaptureOne DSLR software, mainly because it makes RAW files easy to handle in batches. I keep the 'Nikon D1X Daylight' profile embedded the whole way through until I'm ready to print. With the Imacon I do kind of the same thing, scan RAW files and process them into TIFFs using Imacon's Flexcolor software. I keep the 'Imacon Flextight 848' profile all the way through until ready to output.
I print to several devices: an Epson P2200, an Epson 10000, a Xerox Phaser 6200 and various offset presses at our printer's. I only have usable profiles for the Epsons.
I pass virtually every file I print through Photoshop 7 because it gives me the control I want. I usually sharpen a little bit, last thing before converting the profile and printing. No matter what, I do all my PS work without changing the embedded profile until I'm absolutely ready to print. When I go to the Epsons, I convert the profile to the appropriate printer/paper profile (I use Ilford and Epson papers) and turn on soft-proofing just to see what changed. Typically the image loses some contrast and the reds shift slightly to the blue. I try to compensate for that with levels or curves prior to converting. When I click print I watch for the Epson preview, which is not color managed, and if it's heavy on the magenta, I print; if it looks normal, I stop and check my settings. Strange, I know, but it works. There's probably something I could do about it but, as yet, I haven't needed to.
One thing is for certain, if I don't like the print and need to make a change, I go back in the history to before I convert the profile to do it. Whenever I make changes to the file once the output profile is embedded I get color cast problems that I'm unable to correct.
So that's that for the Epsons which are the only cases of true, closed loop color management I use. When I print to the laser, I convert to 'Adobe RGB 1998' and let it rip. If I need to make changes, I go ahead and change them without backing up to the source profile. We mainly use that laser for proofing or printing from QuarkXpress... but that's another thread entirely.
When we go to offset press, I convert to CMYK as soon as I know that's what the destination is. Typically the image files are layed out in Quark or Illustrator once the manipulation and color correction are done so it's CMYK, CMYK, CMYK.
So far, we get good, reliable results and our printers love us because we send them files just like they want them.

That's really all there is. The PS actions are maily for converting the profiles and turning on the appropriate soft proofing.
It's funny, it seems so simple now... but I've wasted a lot of paper and ink getting to this point.

Is that useful to you?
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  #10  
Old 06-11-2004, 12:41 AM
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ljl269 ljl269 is offline
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Very Clear BUT

Thank you Vikki for such a quick response. Mine was not so prompt because I was reading, thinking, & experimenting to give some meat to my reply. Chip has brought-up some of the same issues in 3 subsequent posts so I will make my responses there since they break into subtopics similar to his posts.

I look forward to ur continued input on profiling.

Now I gotta find out how to get this thing to not QUOTE all the time.

Thanks- bye- Larry
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