Photoshop Essential Color Setting 2

CMYK, Gray and Spot Working Spaces

The other three working spaces in the Color Settings dialog box - CMYK, Gray and Spot - can all safely keep their default settings
:

The remaining color spaces are fine with their defaults.

The only exception you'd want to make is if you know in advance that you're going to have your images printed by a commercial printer. In that case, to keep the colors in the prints as accurate as possible, ask your printer if they can provide you with a color profile. If they do provide you with one, click on the drop-down box for the CMYK working space and choose Load CMYK from the top of the list, then navigate to where you saved the printer profile on your computer and select it. In most other cases, sticking with Photoshop's default CMYK working space is fine:

Choose Load CMYK if you have a profile for the commercial printer you're going to use.

Color Management Policies

At this point, we've successfully changed Photoshop's RGB working space to Adobe RGB (or ProPhoto RGB), which is great for images we open now and in the future since they're going to benefit from a greatly expanded range of colors. But what about older images that may have been saved with the default sRGB color profile? Or what if someone asks you to work on one of their photos that was saved and tagged with a different color profile than the one we've set as our working space? What happens when we try to open these images?
We need to tell Photoshop how to handle these color profile mismatches, and we do that in the Color Management Policies section of the Color Settings dialog box. By default, Photoshop is set to Preserve Embedded Profiles, which will keep the original color profile intact, and that's usually what we want so there's no need to change these options:

Leave the RGB, CMYK and Gray color management options set to Preserve Embedded Profiles.

Profile Mismatches
Since we've already told Photoshop that we want to keep the image's embedded profile when it differs from our working space, you may not want to be asked about it every time you open a new image with a conflicting profile. If you just want Photoshop to go ahead and open the image, keeping the original profile intact, leave the Ask When Opening and Ask When Pasting checkboxes for the Profile Mismatches option deselected. Photoshop is capable of opening and working with multiple images at once, all with different color profiles, so it won't cause any problems as far as Photoshop is concerned. However, I'm a big fan of information and prefer to know what's going on. Even if I have no plans to do anything about it, I still like to be kept in the loop. If you're like me, I recommend selecting these two options:

The Ask When Opening and Ask When Pasting options for dealing with profile mismatches.

With these options selected, if you try to open an image saved with a different color profile than your working space, Photoshop will display an Embedded Profile Mismatch warning box, which informs you of the mismatch and gives you choices on what to do about it. You can keep the embedded profile, convert the image to your working space, or discard the profile completely (which defeats the whole point of color management and isn't recommended). The option to use the embedded profile will be selected by default, so unless you have a need to convert the profile to your working space, just click OK to accept it:

The Embedded Profile Mismatch warning lets you know about the mismatch and gives you a chance to change your mind about how to handle it.

Missing Profiles
From time you time, you may come across an image that doesn't have a color profile associated with it, especially if you received the image from someone else who knows little to nothing about color profiles or color management. If you want Photoshop to ignore the problem and just open these images, leave the Ask When Opening checkbox for the Missing Profiles option deselected. However, I would again recommend you select this option:

The Missing Profiles option deals with images that were saved without any color profile information.

With the option selected, if you try to open an image that does not have a color profile associated with it, Photoshop will pop open the Missing Profile dialog box. As with the Embedded Profile Mismatch dialog box we looked at a moment ago, what I like most here is that Photoshop is letting me know the color profile for the image is missing. We then have three different choices for what to do about it. We can leave the image as it is and not worry about the profile, we can assign the working RGB profile to the image, or we can assign a different profile by choosing one from the drop-down list:

The Missing Profiles dialog box.

Missing profiles can be a bit of a tricky situation, especially if the image is not your own, in which case your best bet would be to contact the person who gave you the image and ask for advice on which color profile to use. Assigning a profile can cause drastic color changes depending on which profile you choose, and unfortunately, the Missing Profile dialog box doesn't offer a preview option so you're essentially working blind.
If you don't know which profile to assign, select the Leave as is (don't color manage) option for now and click OK to exit out of the dialog box. Then, once the image is open in Photoshop, go up to the Edit menu and choose Assign Profile:

Go to Edit > Assign Profile.

When the Assign Profile dialog box appears, select the Profile option at the bottom, then choose different color profiles from the list. Keep an eye on the image in the document window as you try out the various profiles and select the one that gives you the best results:

Use the Assign Profile's preview option to choose the best color profile for the image.

Conversion Options

Finally, let's take a quick look at Photoshop's Conversion Options, which control how the colors in the image are handled when we move from one color space to another, or from one device to another (like from your computer to your printer). More specifically, it deals with what happens to colors in the original color space that fall outside the range of color in the new space. For example, you may have colors in your image that look great on your computer screen but can't be reproduced by your printer. These are more commonly referred to as colors that are out of gamut ("gamut" simply means the range of color). The fate of these out of gamut colors is determined by the conversion options. Click on the More Options button on the right of the Color Settings dialog box:

Click on More Options.

This displays some additional options. The one we're interested in is Intent, found in the Conversion Options section. There's two main choices we can select - Relative Colorimetric and Perceptual. Each one handles the color conversion a bit differently. By default, Relative Colorimetric is selected:

Relative Colorimetric is selected by default.

The main difference between the two is that Relative Colorimetric is concerned with accurate color reproduction, while Perceptual cares more about the relationships between colors. Both are capable of giving you great looking prints, but Relative Colorimetric can sometimes produce harsh transitions between colors as it tries to keep them as close to the originals as possible. Perceptual, on the other hand, can produce smoother, more natural looking color transitions, but often at the expense of color accuracy.
As with most things in life, we can't have everything so we need to decide what matters most to us. In this case, the choice is between accurate colors or smoother color transitions. If you do mostly graphics work where color accuracy is very important, stick with Relative Colorimetric. For photographic work, I tend to choose Perceptual because I find it makes images look more natural, even though I know that some of the colors in the print will have shifted from their original values. There's no absolute right or wrong choice here, so I'd suggest printing a few images to compare them and choosing the one you like best:

Perceptual can be a better choice for printing photos (if you're not concerned with color accuracy).

And there we have it! With just a few simple changes to Photoshop's color settings, we've replaced our drab, "general purpose" default RGB working space with one that opens our images to a greatly expanded range of color, we've told Photoshop how we want it to handle images tagged with different color profiles than our working space, we've looked at how to avoid assigning the wrong color profile when opening an image that doesn't have one, and last but certainly not least, we learned how to choose between accurate color reproduction and more natural looking colors in our printed images.