Section 4 - Soft Proofing

A frequently asked Photoshop questions is: why don't my prints match the screen? Generally it's down to poor monitor calibration, but on other occasions it's simply the fact that the user has an unrealistically high expectation of what can be printed. We dealt with monitor calibration in Section 2, however, on the subject of prints I'm reminded of a conversation I had with Thomas Knoll (original author of Photoshop) on my photo trip to Antarctica in January 2009. During this conversation Thomas suggested that much of the problem is really due to overly bright monitors, especially those based on LCD technology. So, if you're still having problems with dark prints after calibration it's worth reducing the display brightness control by 10/15%.

This section will discuss the options and commands associated with the Soft Proof feature. As you work your way through it you'll notice that I haven't included any reference to specific printer driver set-ups. This is because they will be covered in a separate tutorial Photoshop CS4 - Managing Color When Printing, which isn't published yet.

So, what is soft proofing?

Basically, soft proofing is nothing more than using your monitor to simulate a printing device. However, accurate soft proofing is dependent upon the quality and accuracy of the monitor profile and the media profiles for each printer/media/ink combination that you're attempting to proof.  Configuring Photoshop for soft proofing is done via the View > Proof Setup > Custom menu as shown below.

Figure 18

Proof Setup only affects the current or active document on your desktop. So, if you want to define your own default Proof Setup (a wise move) you need to configure the proof setup via the Custom menu option with no documents open. Alternatively, if you do have a document open then hold down the Alt/Option key to activate the ->Default (i.e. Save proof profile) button in the Customise Proof Condition dialog.

The various proofing options are:

• Working CMYK - soft proofs the document using the current CMYK working space defined in the Color Settings dialog.

• Working Cyan, Magenta, Yellow and Black Plate or Working CMY Plates - soft proofs the document using the current CMYK working space defined in the Color Settings dialog.

• Macintosh RGB and Windows RGB - soft proofs the document using the standard Mac or Windows monitor profile (i.e. Apple RGB and sRGB respectively). Both options assume that the simulated monitor will display your document without using color management.

• Monitor RGB - soft proofs the document using your actual monitor profile. Again, this option assumes that the simulated monitor will display your document without using color management.

• Color Blindness - creates a soft proof that reflects colors visible to a person with color blindness. The two soft proof options, Protanopia and Deuteranopia, approximate color perception for the most common forms of color blindness.

The screenshot below shows a typical view of the new Proof Setup (i.e. Customize Proof Condition) dialog in CS4. In this example, I'm showing the configuration required for simulating Premium Glossy Photo Paper on an Epson Stylus Pro 3800 inkjet photo printer. From this dialog you can easily select, configure and save your own customised soft proofing setup for any number of different printer profiles.

Figure 19

You begin the process by choosing the Profile from the Device to Simulate pop-up menu. In the example shown above I have selected the Epson Stylus Pro 3800 profile for Premium Glossy paper (i.e. Ep3800_PremGloss_2880_Colorful). In your case it will be the profile for the media that you want to simulate on the monitor.

Preserve RGB/CMYK Numbers

This option will only be available when the document and profiles are in sync, i.e. both are RGB or both are CMYK. Selecting the Preserve RGB/CMYK Numbers checkbox will usually result in a quite awful looking display, so don't make the mistake of choosing that option. Basically we are simulating how the document will appear if it's not converted to the actual device profile.

One use of this option is to enable you to see how the document would print if the appropriate media profile is not selected in the Print with Preview dialog. Normally it's best the leave the checkbox unchecked.

Rendering Intent

Rendering Intent is the setting that appears to cause most confusion and it's generally worth trying both Relative Colorimetric and Perceptual. Typically Relative Colorimetric will be best but some highly saturated documents will benefit from choosing Perceptual.

Use Black Point Compensation

I described Use Black Point Compensation previously when discussing the conversion engines. Typically, it will be best to keep it checked.

Display Options (On Screen)

There are two options (or checkboxes) shown in this section of the Customise Proof Condition dialog. The first: Simulate Paper Color allows you to simulate, on the monitor, the shade/color of the paper white. The second: Simulate Black Ink will enable you to simulate, on your monitor, the dynamic range defined by the media profile (i.e. how dark black will appear on the media you're printing to). Note that selecting the Simulate Paper Color checkbox will cause the Simulate Black Ink to be selected and greyed out. Not all profiles will support both options.

The resulting soft proof display can be quite disconcerting at first. By this I mean that the overall tone of the image may tend to look compressed or slightly color shifted (e.g. white takes on a blue cast). This can often occurs when using printer profiles that were created from scanner based profiling applications. In such circumstances it's probably best to leave the Simulate Paper Color and Black Ink options unchecked.

To save the customised proof setup simply choose the Alt/Option+Save button and give the soft proof profile a name that clearly indicates the printer/media combination for which it was created. The name of a saved soft profile will be appended to the bottom of the list immediately below Color Blindness options (Figure 18 above). A comprehensive, albeit quite old, tutorial describing the technique of soft proofing can be found at the following link: here

Section 5 - Managing the Document Color Space

As with other aspects of color management we find that color space conversion and profile-embedding hasn't changed in Photoshop CS4. I suppose you could say that since it wasn't broken in CS3 there was no need to fix it. Either way, for many Photoshop newbie's it's difficult to appreciate the difference between  embedding a profile and converting to a profile, so I'll try to shed some light of the differences below.

Assign Profile

So what does Assign Profile do and when do we use it?  Assign Profile allows you to associate any profile of your choosing to a document. The command is intended for only a few limited uses, e.g. documents that have been imported into Photoshop using a Twain module or a scanner package that has no means of embedding an ICC profile.

Itís important to note that assigning a profile does not change the document (i.e. it will not change the RGB/CMYK numbers or pixel values). Assign Profile simply provides Photoshop with a description of the actual color space that you wish to edit and view the document in. In other words it changes the document appearance or meaning of the RGB/CMYK numbers.

Figure 20

• The Don't Color Manage this Document: option is used to instruct Photoshop to remove an existing embedded profile (sometimes referred to as untagging).

• The Working RGB: option tags the document with the current default working space profile as defined in Color Settings.

• The Profile: popup option allows us to assign a profile other than the default Working Space profile. In the above example I chose to assign a customised profile for a Nikon scanner.

Other potential uses for Assign Profile include the removal of an embedded profile (i.e. don't color manage the document).

Convert to Profile

Convert to Profile is basically an enhanced version of the old Photoshop 5.0 Profile-to-Profile command, the main difference being that with Profile-to-Profile you were able to define the source color space. In all subsequent versions of Photoshop, which includes CS4, this cannot be done since the source profile for the image is predefined and locked. The only way that the source profile can be changed is via the Assign Profile command discussed above.

Figure 21 - Basic mode

Figure 21 above shows the new Convert to Profile dialog. Notice the button labelled Advanced, which when clicked expands the dialog to such a much larger range of advanced options (figure 22 below).

Figure 22 - Advanced mode

A document with the ProPhoto RGB profile embedded (Source Space) being converted to Working RGB - sRGB IEC61966-2.1 (i.e. the Destination Space). Whenever we make this conversion it will be the profile for the destination space that is embedded within the document when saved. Convert to Profile changes the RGB/CMYK numbers (i.e. pixel values) in order that the document appearance is maintained. The Preview checkbox allows the user to compare the conversion with and without Black Point Compensation, Dithering, and any one of the four rendering Intents. The ability to preview the conversion is a real boon and shouldn't be ignored, so use it to your benefit.

Also notice that the screenshot shows the Intent set to Relative Colorimetric. This was the default Intent I chose when I configured the Color Settings dialog earlier. However, as with many Photoshop setting the Intent is "sticky", which means that if I was to change it to Perceptual then the next time I choose Convert to Profile the Intent will be set to Perceptual.

Section 6 - Printing

Whilst printing from within Photoshop is discussed in separate tutorial it's still worth providing a brief overview to round off this essay on color management.

The screenshot shown below shows the color management options within the new Print dialog box that enables you to define the source and destination (target) color spaces along with the rendering intent used to convert the document between the two.

Figure 24 - Print dialog (click image for larger view)

Even if you've been using a version of Photoshop as recent as CS2 or CS3 you'll immediately notice that the Print dialog has been reworked, again. We also now have new option for Gamut Warning and Paper White. You'll also notice that Color Management is still the default view for this dialog, but the preview window is now fully color managed with the ability to soft-proof images. Anyway, to keep things simple I will focus on only those settings that fall within the Print and Options area in figure 24 above. I will also give a brief summary of each option and hopefully give you better idea which combinations are best suited to particular print tasks:

Print:

• Document: denotes the ICC profile embedded within or assigned to the source document. The example shown in figure 24 shows sRGB IEC61966-2.1, but it could be any number of user specified alternatives (e.g. ProPhoto, Adobe RGB (1998), ColorMatch). If the document has already been converted  to a printer/media profile using the Convert to Profile command, then the printer profile color space will be reflected here.

• Proof: this field will normally display as (Profile: N/A). Once it's activated via the radio-button it tells Photoshop to convert the document on-the-fly from the source documents color space to the ICC profile shown in brackets. You can only alter the destination profile from within the Proof Setup dialog (see: Photoshop View menu). Also, note that you'll only ever need to use this option if you are intending to make Hard Proofs or Match Prints (i.e. emulating another printer such as a press), therefore I don't intend to elaborate on this workflow.

Options:

• Color Handling  - this is the pop-up menu  from which you choose the preferred method of managing color when printing from Photoshop CS4. By adopting this approach Adobe have separated the workflow aspects of  printing from the media choices. It was first adopted in CS2, and modified slightly in CS3. Anyway, there are still four different color handling options, but the names used by CS3 and now CS4 are slightly different  from those in CS2. Also, note that each has its own associated preset configuration within the Print dialog thereby helping the user avoid erroneous settings.

1. Printer Manage Colors - with this option Photoshop instructs the printer to carry out the conversion between the document color space and the printer vendors preferred color space. Photoshop will not change (convert) the document if this option is selected. This is the most appropriate option when you don't have ICC media profiles for your particular printer/media combination.

2. Photoshop Manages Colors - with this option Photoshop will convert the document to the printer/media profile selected that you have selected in the Printer Profile pop-up. Many desktop printers are now supplied with generic media profiles, but much more accurate prints can be obtained if custom profiles are used. However, for this option to work correctly color management must be switched off in the printer driver.

3. Separations - this option is used when printing CMYK images where each channel is handled separately. If your document is RGB the option will be greyed out.

4. No Color Management - with one important difference, this option is similar to the Printer Manages Colors option described above. The difference being, that with this option, Photoshop will not instruct the printer to change to convert the document. This option is intended for special cases such as printing custom profile targets that require document color management to be turned off in both Photoshop and the printer driver.

• Printer Profile - as its name implies this is the pop-up menu from which you choose the ICC profile associated with the printer/media combination you'll be using. This pop-up will only be active when Photoshop Manages Colors is selected in the Color Handling pop-up. By default, it will actually show the document color space, so make sure that you don't forget to choose the appropriate printer/media profile before hitting the Print button.

• Rendering Intent and Black Point Compensation - again, depending upon your choice in Color Handling one or both of these settings may be greyed out. Irrespective of whether it's greyed out or not, most desktop photo printers (inkjets) will ignore these two settings when Printer Manages Colors is selected from the Color Handling pop-up.

• Proof Setup - by default, this pop-up menu is greyed out and will only be activated when the Proof radio button is selected. As mentioned above, this option is normally only used when simulating or proofing other output devices such as a Press. The Simulate Paper Color and Simulate Black Ink work in the same way as they do in the Customize Proof Condition dialog described in Display Options, Section 4 above. However, it is important to note that they are tied to Proof printing, so don't expect them to be available when Document is selected.

• Description - this is a useful addition to the Print dialog in so far as it provides short explanations for each of the settings and options. The description itself is triggered when you hover the mouse over the various buttons and pop-up menus (e.g. Color Handling, Rendering Intent, Black Point Compensation, etc).

The last few items that I want to mention are the new and very welcome Gamut Warning and Paper White checkboxes. With these new options and Match Print Colors we can now configure the print Preview display so that it shows a screen rendered soft-proof of the document - as with CS3 the preview shown in Print dialog is fully color managed. However, this time round it's possible to preview the proof with and without the effects of paper white.

Section 7 - Saving Documents

Save As

Again, whilst saving your documents is not directly related to color management the Save As dialog throws up a host of useful features. The Embed Profile checkbox is very important and will reflect your choice of Color Management Policy, which was discussed earlier. Notice that the dialog even informs us which profile is being embedded.

The screenshot shown below (figure 25) is how the dialog appears on a Mac OS X system; the Windows version looks slightly different, but they are functionally identical.

Figure 25

The other save options present in the dialog are those associated with Layers, Alpha Channels, Annotations, etc. Again, you can choose to uncheck them and so save the image without the layers, etc. The Save As a Copy feature is engaged by default as soon as you uncheck Layers; this prevents you trashing a lot of hard work.

Hopefully the material presented in this essay has been helpful and improved your understanding of Adobe's approach to managing color in Photoshop CS4. As noted throughout the essay there is vast body of material to be found all over the internet. A simple search using "google.com" and the key words Color Management is all that is required.