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Color Management and Adobe Photoshop

Nigel Lew

New member
Hi folks, I wrote this a while ago for an art news site but they like to keep disappearing. Hope it helps someone.

Here is a comprehensive guide to getting prints to look like they do on your monitor.

Color Management and Adobe Photoshop

Color management, and creating a workflow to get from your scanner to the printer can be a little tricky. There are a few things that need to be understood first before we can accomplish this. By following the steps outlined in this column you will easily be able to grasp the concepts involved in color management and ensure your prints come out looking exactly like they do in your "working space" or on your monitor.


Preface


In order to understand color management, it is important to get your hands around some of the workflow. It is also important to understand a little bit about the ICC itself. The ICC or "International Color Consortium" was created in 1993 by a number major corporations with the goal of assisting end users in creating consistent, color, throughout the entire reproduction process. ICC profiles are a means by which one device can translate the same color information to another. This process is applied in graphics programs like Adobe Photoshop, and created in color management systems like X-rite’s Pulse or ColorVision’s Spyder software.

How is a profile created?


In order to have a fully color controlled environment you must have all devices displaying or printing color, profiled. How is this accomplished? Color management software (CMS) takes readings from your specific devices and compares their color with reference files of what color “should be” as defined by the ICC. For example, to profile a scanner you would scan in what is called an IT8 target. This scan is then compared with a reference file by the CMS. The differences between what the reference file says the color should be, and what the color your device actually output is meat of the profile. Basically, a profile says what’s not perfect about your particular device. If your scanner always seems to scan things in a little green, or your printer always seems to print things with a magenta cast-these are the things that are taken into account when color profiling your devices. To complicate matters a little further, this process also takes into account the differences in color between various paper and ink combinations.

Understanding Your Environment

Color Model: When you hear the term color model we are referring to the method from which we define or classify the color we are to work with. Examples of such are RGB, LAB, CMYK, etc.
Color Space: A color space is simply a variation of your color model. For instance, within your RGB framework some common variations are, sRGB, Adobe RGB, and so on. Some of these spaces are better for display e.g. sRGB and Wide Gamut RGB while other color spaces are more suited to printing e.g. ColorMatch RGB and Adobe RGB.

Now, it is important to note that every device in our workflow utilizes it's own unique color space. Meaning, while your monitor, scanner, and printer will base their color spaces basically on what we can see their actual gamut (range of colors) will differ. This is where we lose our consistency across devices. This is the problem we must attend to.

Color Management Using Adobe Photoshop: Step-by-Step

Okay, so now we’re ready for the whole process-it’s a big one, so keep with me. In this section I will describe how color management works with entry-level CMS’s like Monaco EZ Color or ColorVision’s Spyder2-programs like these utilize actual hardware colorimeters for monitor calibration and a reflective target for scanner calibration. Scanning the printed target with your home scanner creates the printer profile. Entry-level programs like these generally retail between $150 and $500.


Step One: The Monitor

This step is quite easy and is generally conducted entirely in the CMS program of your choice. The CMS will guide you through the process of adjusting you monitor brightness and contrast to its proper settings and then, with the hardware colorimeter, take readings of the colors your monitor can produce. Your CMS should also set this profile as your default profile for your operating system. Take note if your CMS doesn’t already explain it, you should remove Adobe Gamma Loader.exe from your Startup folder after creating a new monitor profile. AGL is a very minimal monitor correction tool and will conflict with your newly created profile.

Step Two: The Scanner

For the scanner profile you will be using an IT8 target. This is a printed color reference of approx. 250 color patches. These targets are manufactured under strict controls and are measured by ICC approved methods to produce accurate reference files. Kodak, Coloraid, and Fuji are the major manufacturers of IT8 targets and should be included with your CMS package but may be a required separate purchase. There are two forms of IT8 targets: reflective and transparent. Reflective targets create a generally consistent profile for scanning reflective images. Transparent IT8 targets are printed on to the specific film to be profiled and therefore cannot be used as globally as reflective targets.

Profiling of the scanner involves scanning the IT8 target under the same conditions that will be used to scan originals. This has to be taken to the nth degree, as every setting in your scanner software needs to be exactly the same for scanning the target as it is for every other original that you will scan. Turning all hue/saturation/brightness/contrast controls off in your scanner software generates the most effective profile. Any auto correction adjustments need to be turned off so the same conditions the profile gets generated under will apply to each consecutive scan.

At this point you will scan in the IT8 target, most likely at 200 dpi, and save the file. Some CMS’s will have you scan the IT8 target out of their own interface, but I would recommend scanning the target with the same application that you will be using in the future-if possible. When scanning into an application like Photoshop, remember to save the image without any profile attached (in Photoshop when saving you will see a checkbox under Save Options>Color that is labeled ICC Profile-make sure this is not checked). Now load this image into your CMS, it will take this image and calculate the differences between what your scanner sees compared to what the colors of the IT8 “really” are.

Step Three: The Printer

Now, the last piece to the puzzle, printer targets. Like transparent IT8 targets, printer targets are more complex. Similar to film, different papers or media can produce incredibly different color results. This has to be taken into account in the profiling stage. When creating a printer profile, you are essentially creating a description of the differences between what is ideal color and what is the result of the specific paper/ink/quality setting you choose. A profile created for a professional glossy photo paper will generally not produce good results if used to print on a matte heavy weight paper. The same holds true for differences in ink or quality/speed settings.

In your CMS you should be given the option to save your printer target for printing within your chosen graphic app. If asked choose not to apply a profile when opening. In Photoshop choose File>Print with Preview. Change the Output dropdown to Color Management. Under Source Space choose Document. Under Print Space choose Profile: Same as Source. You are now set up in Photoshop to print your profile target. You aren’t done yet! Now go into your printer driver software and set any color options to none, or zero, or whatever shuts off any color changes by the driver. Now print your target.

This is where professional level CMS’s and entry level ones differ. At this point with the entry level you will scan in the printed target and the CMS will actually use the before generated scanner profile to correct the scan, so it can the correct your printed target. A professional level CMS will have a separate hardware device designed specifically for reading printed media targets.

Step Four: Utilizing the Profiles

Okay, now that we’ve created all of the profiles-time to implement them. Your monitor profile should be getting applied upon startup by your operating system, so let’s move on to your scanner. Scan in an image-once again using the exact same settings that were used to create the profile (other than resolution). In Photoshop choose Image Menu>Assign Profile. Then choose Profile: Your Scanner Profile. Having done all of the previous steps in Photoshop correctly, you should now be amazed at how your image colors changes to appear incredibly like the original that you’ve just scanned in.

From here go to Image Menu>Convert to Profile and choose Working RGB from the profile selections. This will convert your document to the native RGB working space of Photoshop. When printing you will apply the printer profile by once again choosing File>Print with Preview, select Document as your Source Space (which this time should be your Working RGB space) and in your Print Space choose Profile: Your Printer Profile. Remember once again to disable any color options in your printer driver. Finally, Print!

Other Notes on Profiling


I would recommend using Relative Colorimetric as your Rendering Intent when doing the Convert to Profile step and when printing with Print with Preview out of Photoshop. Rendering intents control how the profile is applied to either the scanner or printed image. Relative Colorimetric has proven to be the best in my testing. Read the documentation that came with your CMS in order to learn more about the other available rendering intents.

Profiles are only as accurate as the CMS that generates them and the size of the targets that are used to generate them. Packages in the $150-$500 price range generally have around 75-250 patches, while $2000 and up gets you 729 patches or more. Also, the more expensive packages rely on physical hardware devices to generate printer profiles, while the less expensive packages use your scanner as the print colorimeter. In addition, the more expensive packages have numerous options for the edition of the profiles you create.

Sources cited in this column are:
Adobe®
xrite/monoco®
Colorvision®
Shawn Tolle, Technical Consultant.
 

Rachel Foster

New member
I've printed this for study, Nigel. It looks extremely helpful. I bought Spyder a few months ago but messed up my display with it. I'm screwing up my courage to give it another go.

Thanks for posting this.
 

nicolas claris

OPF Co-founder/Administrator
Hi Nigel
interesting post that will help a lot of folks here.
As discussion may arrise, I made it a "sticky" (stay on top of list of its forum)

BTW, I have deleted your twin post…
 

Nigel Lew

New member
Thanks, I must have clicked back or something. I seem to recall an issue when I was formatting it a bit. I am going to run through it real quick since its a tad old but I suspect the info is still spot on.

Thanks very much for making it a sticky :)

Nigel
 

Nigel Lew

New member
Thanks, I think it is fine now. I will add you folks and feature you on my directory in my sig.
I should have it done shortly.

Nigel
 

Nigel Lew

New member
I've printed this for study, Nigel. It looks extremely helpful. I bought Spyder a few months ago but messed up my display with it. I'm screwing up my courage to give it another go.

Thanks for posting this.

Sure, if you have any issues let me know. Occasionally, creating a monitor profile gets mucked up. It can have to do with a range of things like glare on the monitor, the monitor itself, etc.

You will typically get the best results on a crt. There are some flat screens that will do the trick but I seem to recall they are a bit pricey.

If it really messes things up just try it again.

From the article remember..... "you should remove Adobe Gamma Loader.exe from your Startup folder after creating a new monitor profile. AGL is a very minimal monitor correction tool and will conflict with your newly created profile."

hope that helps,
Nigel
 

Jack_Flesher

New member

Other Notes on Profiling


I would recommend using Relative Colorimetric as your Rendering Intent when doing the Convert to Profile step and when printing with Print with Preview out of Photoshop. Rendering intents control how the profile is applied to either the scanner or printed image. Relative Colorimetric has proven to be the best in my testing.

While I agree with this for most cases, you'll find that using perceptual sometimes generates better results -- like when moving from a very large space like Profoto to a relatively small space like sRGB. RC trims out of gamut colors to the nearest in-gamut color which can cause blocking, where perceptual compresses them over a broader range eliminating obvious blocking in the smaller space. The downside to perceptual is it can alter in-gamut colors so isn't as good at preserving absolute color accuracy on in-gamut colors in the smaller space... Note that for either of the above, you should also use Black Point Compensation (BPC).

Note too that rendering intents are used in the background when files are sent to printers -- the image's working space gets converted to the printer profile. If you print from CS per above, the default conversion method is set in your color settings dialog (Edit>Color Settings). Here, some brands of printers prefer Perceptual over RC for general use; as such it's best to experiment with both. Generally speaking, Epson pigment printers tend to prefer RC over Perceptual.

Cheers,
 

Nigel Lew

New member
I concur Jack. I am going to work on it a bit as it is a few years old and things have actually changed. It is still a good basis for folks to get their head around the process. I tried to make it as easy to understand as possible.

Its nice to find some folks who are printers. It is certainly a unique demographic to be in.

thanks for the discourse.
Nigel
 

Andrew Rodney

New member
While I agree with this for most cases, you'll find that using perceptual sometimes generates better results -- like when moving from a very large space like Profoto to a relatively small space like sRGB.

Unless you've got some V4 working space profiles (and I've yet to find any but sRGB), you might be selecting Perceptual but you're not getting Perceptual, that table, as well as the Saturation table do not exist in simple v2 matrix profiles.

I've requested Adobe simply gray out the intents not possible to use when encountering such profile because it confuses users. You're picking something that just doesn't exist in the profile.

LUT based profiles, the vast majority of true output profiles do have all three tables.
 

Doug Kerr

Well-known member
Hi, Joseph,
Can anyone tell me what the difference between the "Working RGB - sRGB IEC61966-2.1" and "sRGB IEC61966-2.1" options in Photoshop are?
Perhaps the listing with the "Working" prefix is a duplicate listing for the color space that is currently in effect, just to make that clear.

Are those two entries in the same list (perhaps in the "Color Settings" dialog)? (I use Photoshop so rarely that I don't know where all these things appear.)

Best regards,

Doug
 

Joseph Westrupp

New member
Hi, Joseph,

Perhaps the listing with the "Working" prefix is a duplicate listing for the color space that is currently in effect, just to make that clear.

Are those two entries in the same list (perhaps in the "Color Settings" dialog)? (I use Photoshop so rarely that I don't know where all these things appear.)

Best regards,

Doug
They both appear in a list of possible color spaces on invoking the Convert to Profile command. And it seems to have nothing to do with the current profile--there are a number of different color spaces with the prefix "working".

Incidentally, if not Photoshop, what do you use?
 

Doug Kerr

Well-known member
They both appear in a list of possible color spaces on invoking the Convert to Profile command. And it seems to have nothing to do with the current profile--there are a number of different color spaces with the prefix "working".
In my Photoshop, in the Convert to Profile dialog, in the dropdown for Destination Space, at the top are listed the currently nominated color spaces of three different classes: RGB, CMYK, and Gray.

For example if,in Color Settings, I have set as my RGB working color space "ProPhoto RGB", then in Convert to Profile, the Destination Space dropdown list has as one of three entries in its top section, "Working RGB - ProPhoto RGB". That is true even if the current active space for the current image is something different.

That top section also lists, in a similar way, the currently-nominated color spaces of the CMYK and Gray classes.

Thus, we could easily choose (working only only that top section of the list) to convert the image to the profile for our currently nominated RGB color space, or our currently-nominated CMYK space, or our currently-nominated Gray space.

But of course all the spaces, along with many others, are listed in later sections of the list (without the "Working" prefix).

Does this make sense with respect to your observations?

Incidentally, if not Photoshop, what do you use?

I do most of my image editing in Picture Publisher, Version 10, a program originally developed by Micrografx (then located near Dallas). They later sold the rights to it to Corel, who basically let it go to its eternal rest as it was in version 10 (not wanting it to compete with their own native products).

In, my opinion, the human interface for many functions is much easier to use than in Photoshop. That may just be a matter of my history with it. But often, I will ask of the experts here, "Say, in Photoshop, how can I do such-and-so." Often, after elaborate replies and misunderstandings about what I am asking about, the answer turns out to be, "Well, you really can't", or you can, but in a way that I find extremely clumsy.

It of course does not have many features of Photoshop (no actual layer structure, for example), and many of its functions do not represent today's capabilities and level of performance (its vintage is 2001). It will work with many Photoshop plug-ins, but often with limitations (sometimes it looks as if they are going to work, but just don't).

Thus I will occasionally move an image into Photoshop to perform certain operations, then perhaps back to PP10 to wrap it up.

Best regards,

Doug
 

Joseph Westrupp

New member
In my Photoshop, in the Convert to Profile dialog, in the dropdown for Destination Space, at the top are listed the currently nominated color spaces of three different classes: RGB, CMYK, and Gray.

For example if,in Color Settings, I have set as my RGB working color space "ProPhoto RGB", then in Convert to Profile, the Destination Space dropdown list has as one of three entries in its top section, "Working RGB - ProPhoto RGB". That is true even if the current active space for the current image is something different.

That top section also lists, in a similar way, the currently-nominated color spaces of the CMYK and Gray classes.

Thus, we could easily choose (working only only that top section of the list) to convert the image to the profile for our currently nominated RGB color space, or our currently-nominated CMYK space, or our currently-nominated Gray space.

But of course all the spaces, along with many others, are listed in later sections of the list (without the "Working" prefix).

Does this make sense with respect to your observations?
So it just groups the current color spaces for convenience. Slightly odd, but I guess it could be handy if you have a massive list of color spaces.

I do most of my image editing in Picture Publisher, Version 10, a program originally developed by Micrografx (then located near Dallas). They later sold the rights to it to Corel, who basically let it go to its eternal rest as it was in version 10 (not wanting it to compete with their own native products).

In, my opinion, the human interface for many functions is much easier to use than in Photoshop. That may just be a matter of my history with it. But often, I will ask of the experts here, "Say, in Photoshop, how can I do such-and-so." Often, after elaborate replies and misunderstandings about what I am asking about, the answer turns out to be, "Well, you really can't", or you can, but in a way that I find extremely clumsy.

It of course does not have many features of Photoshop (no actual layer structure, for example), and many of its functions do not represent today's capabilities and level of performance (its vintage is 2001). It will work with many Photoshop plug-ins, but often with limitations (sometimes it looks as if they are going to work, but just don't).

Thus I will occasionally move an image into Photoshop to perform certain operations, then perhaps back to PP10 to wrap it up.

Best regards,

Doug
Wow, that's dedication to software. I suppose there's no reason to change if it does everything you want.
 

Doug Kerr

Well-known member
So it just groups the current color spaces for convenience. Slightly odd, but I guess it could be handy if you have a massive list of color spaces.
Yes, I guess so. Or if you can't remember what your favorite Gray color space is!

Wow, that's dedication to software. I suppose there's no reason to change if it does everything you want.
Well, I'm a bit reactionary!

Here are examples of just a few little things I prefer about PP10 over PS:

1. I often do many "Save As" operations in processing an image file (mostly to make different versions for different purposes). I like to be able to set the JPEG parameters and them have any Save as JPG just follow those. In PS, each time I do a Save As JPG, I have to deal with the dialog wanting to know what parameters I wish to use.

2. Often I will want to crop an image to a known aspect ratio (perhaps determined by the intended use), but adjust the absolute dimensions (and placement) by eye. In PP10, I can set that ratio. Then when I invoke the mask tool, a mask of that aspect ratio will appear, which I can move around and resize using the two mouse buttons (the aspect ratio being held). Then I just crop to the mask with a button for that (or a keyboard shortcut).

3. In fact, it is very nice to be able to move around a mask (and size it) using only the mouse (both buttons potentially involved). In PS, one has to use Shift to move between "change size" and "change origin" modes. I may not have another hand available for that (sandwich in my left hand, for example).

4. In the PP10 Clone tool, both the "inlet" and "outlet" areas are continually visible, so one can always see just what is coming from where and going where. It is also easier than in PS to reset the current location of the "inlet" area (requires Shift, so I do have to set down my sandwich). You need not click on the new location of the inlet; just move the entire tool so the inlet is at the desired initial pickup location, hold Shift (which freezes the inlet there), move the mouse until the outlet area is at the desired initial outlet location, then release shift and paint away.

5. I like to have custom buttons for functions I use a lot.

Just personal preferences, of course!

Best regards,

Doug
 
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