This is a good thing because existing users migrating from
an earlier version tend to be up and running fairly quickly. Also, why
change something that works well. As such, this essay is, for the most
part, simply an update of earlier versions rather than a rewrite. I've
also made it as version agnostic as possible.
Note: The guidance provided in
this essay is compatible with Photoshop version 9 (2009) and higher
Section 1 - Color Management
Primer
Components of a Color
Management System
A typical imaging system will consist of input and
output devices, for example: scanners, digital cameras, monitors, and
printers. Unfortunately, with such a diverse range of device types,
technologies, and gamut limitations, it's inevitable that they will
each reproduce the same color differently (i.e. color is device
dependent). Obviously, this will present significant problems
when working with documents originating from different sources, and
will be further complicated when the same document is destined for
different types of output device. Therefore, some means of ensuring
that color data is reproduced in a predictable way throughout the
entire imaging system is essential. This is the purpose of a Color
Management System (CMS).
A color managed system comprises three basic
components, namely: -
-
A device-independent color space - this is usually
referred to as the Working or Reference color space.
-
ICC profiles for each device (i.e. printer,
scanner, monitor, digital camera, etc.) that will accurately describe
the unique color characteristics of each device.
-
A Color Matching Module (CMM) that will
interpret the information contained within the device profiles and
carry out the instructions on how the color characteristics of each
device should be treated.
Color Numbers, their
Meaning and ICC Profiles
A digital image will usually comprise many millions
pixels, each of which is represented by a numeric values. The values
assigned to each pixel will describe many attributes but in this
essay it's the color value or mix (e.g. RGB value) that we're most
interested in. As I have already mentioned, when a color is
device-dependent, the appearance of pixels with identical values
will very often differ because each device has its own unique way of
translating the color "value" or "number" into visual color. The role
of ICC profiles is to ensure that discrepancies that result from
the widely differing color characteristics of each device are known to
the color management system. If we were discussing spoken language
rather than color, then the ICC profile would be synonymous with a
translator.
Device profiles come in two basic forms, i.e.
Input and Output profiles. Input profiles typically describe
the color characteristics of scanners and digital cameras, whereas
Output profiles describe devices such as monitors, printers and
film recorders. Input profiles are often referred to as one-way
since they represent the source device. This means we can
never convert a document into the color space of our scanner or digital
camera. Output profiles, on the other hand, are two-way meaning we
can convert From or To them. For example, we can convert a document
with an embedded monitor profile into one that has a color
profile describing a printer, or vice versa.
The
application software and drivers associated with most consumer class
inkjet printers, film and flatbed scanner applications
have been ICC aware for some time now with many vendors usually
choosing sRGB as their preferred color space on the Windows platform. Clearly, these
vendors are doing some work behind the scenes so as to keep things
simple for the user, which isn't necessarily as wise as it might first
appear. The reason being that sRGB isn’t generally regarded as appropriate
for high quality image editing, especially when print or film output is
required. So, to overcome this some vendors also provide the user with
the option of choosing from a small selection of alternatives. For
example, printer vendors such as Epson provide generic ICC profiles
with their photo class printers, although its generally accepted these
profiles are rarely as accurate as users would like. Nevertheless, they
are getting better with each new generation of printer. As a rule,
truly accurate color matching usually requires customised ICC profiles
for each device and/or media type. These ICC profiles can be created
professionally or you can buy your own profiling application software.
Why bother with Profiles
and Color Management?
Even though color correction and color management
are not the same thing they're often confused with each other,
especially by the novice Photoshop user. Explaining the difference can
very often lead to even more confusion, but hopefully the following
explanation will provide some help.
We have already established that the color
characteristics of most imaging devices tend to be unique to that
device. Likewise, it's very rare for them to be truly linear (i.e.
R=G=B=Neutral). Sometimes this second characteristic is referred to as
the device being "badly behaved"; with scanners and printers being good
examples of badly behaved devices. Obviously, it would be extremely
difficult to edit a document where a group of pixels with values of
R=G=B=128 (i.e. grey) actually appeared on the monitor to be
significantly non-neutral. In such circumstances color correction would
an absolute nightmare. To overcome these discrepancies we usually carry
out all our editing in color spaces that are "well behaved" or
independent of any specific device. In Photoshop "well behaved" color
spaces are more usually referred to as the Working Spaces, and
are always characterised by RGB values that appear neutral when all
three are equal. These Device Independent color spaces do not
behave like, nor are they influenced by, any real world device. So, in
this respect it could be argued that Working Spaces are based on
synthetic color spaces.
So, we have Device Profiles and
Working Space Profiles - how do they interact?
The first thing we need to understand is that for
any color profile to be useful to the color management system it
must conform with the ICC standard. In fact, you'll more often see such
profiles referred to as just ICC profiles. Anyway, without the aid of
device profiles the accurate translation of the document color data
(the RGB numbers) from the scanner or digital camera into the
Working Space will prove very difficult, if not impossible.
Likewise, without the aid of accurate media specific printer profiles,
the translation from the Working Space into the color space of a
digital printer will prove equally difficult. We also need an accurate
monitor profile so as to ensure that what we see on the monitor is a
true representation of the document color.
The following flow diagram demonstrates a typical imaging workflow,
with the document being passed between devices: - from scanner/digital
camera - to - computer - to - monitor - and printer.
Typical Imaging System
So, the main benefit offered by color management is
that the process of color correction in your editing software can be undertaken in the knowledge
that the document displayed on the monitor is an accurate visual
representation of the original subject, and that the final print will
accurately reflect the colors of the document being displayed.
In above
diagram, I've shown and ICC profile digital camera. However, this not
always the case. For example, Adobe create DCP profiles for all cameras
supported by Camera Raw and Lightroom. In some cases, (e.g.
Canon, Leica, Nikon,
Olympus, Panasonic, Pentax and Sony), Adobe provides multiple profiles
for each supported camera model. Whilst these are not interchangeable with the ICC input profiles used by other raw editing applications such as
Capture One, they work in the same way.
Document Specific Color
Just
like its predecessors Photoshop
continues to use document specific color settings, Actually, the
Working Space that's chosen in the Color Settings dialog has a
direct bearing on only three types of document, viz.: -
-
The default color space of new documents created via the
New
command found in the File menu
-
Existing documents without an embedded ICC profile
-
Imported documents with no embedded ICC profile (i.e. untagged
documents), which might include scanned documents or those
emanating from digital cameras.
Document
specific color means that it's the ICC profile embedded within the
document that determines how it will be displayed (it's appearance) and
not the default Photoshop Working Space. With Photoshop you can have multiple documents, each in
its own unique Working Space, open at the same time, and each
will be displayed accurately. Of course all of this assumes you're
using an accurately calibrated and characterised monitor.
Section 2 - Monitor Calibration
and Characterisation
Monitor calibration and characterisation (profiling)
is probably the most important aspect of a color managed workflow; yet
many users remain oblivious to the issues poor monitor calibration can can
have on their documents. So, what is calibration, why is it so
important, and why is it different from characterisation?
Calibration is a process whereby a device is brought
to a standard state (e.g. a color temperature of 6500K and gamma of
2.2), whereas characterising the monitor is the process of determining
how the monitor represents or reproduces color. We characterise the
monitor by measuring how it displays known color values, then creating
an ICC profile. The ICC profile is simply a data file that includes a
description of the monitors’ color handling characteristics (i.e. its
gamut). The calibration data will also be written into the ICC profile.
As I've already mentioned, Photoshop then uses the monitor profile to
automatically optimise the display of documents. It does so by carrying
out an on-the-fly conversion between your document profile (e.g.
ProPhoto RGB, Adobe RGB, and sRGB) and your monitor profile.
This conversion does not alter the actual document in any way; just how
it
appears on on the monitor.
Software only monitor calibration
applications of which there are very few remaining (Apple Display
Calibrator Assistant being one) use the human eye to determine tone and color differences
between a series of white/grey/black/color patches. However, it
should go without saying that the eye isn't the most accurate
method of measuring these differences. Therefore, my recommendation
would be to use a hardware based system such as the
Datacolor Spyder X,
X-rite Photo ColorMunki or
X-rite Photo i1 Display Pro.
Better still are monitors with built in calibration tools (e.g. BenQ,
Eizo and NEC). Typically, these are monitors intended for professional use, and
will have much better colour and greyscale performance than consumer
oriented monitors.
Section 3 - Photoshop Color Settings
The
Color Settings dialog is the control room for the Photoshop color
management system, and like all control rooms it can appear
complicated. If you're upgrading from an earlier
version of Photoshop you'll likely have Color Settings configured to meet your needs,
and it's probably best that you stick with those settings. On the other
hand, if new to Photoshop then pour yourself a cup of strong coffee and pull
up a chair because what follows is not always easy to understand, and
may take a few attempts to sink in.
Whether you use Mac or Windows the appearance
and list of options within the Color Setting dialog, and elsewhere
within Photoshop, is to all intents and purposes identical. So,
begin by opening the Color Settings, which is found towards the
bottom of the Edit menu.
Figure 1 - Photoshop Default Color Settings
The first thing that I will draw your attention to
is the box at the bottom of the dialog labelled Description. As
the mouse is moved across the various pop-up menus, etc. you should see
a short but informative explanation of what each menu does. Also note
the button labelled More Options; it's probably best that you
select it now, as it will let you see the complete Color Settings
dialog rather than the simplified version.
The default RGB color setting depends upon your
geographic location you'll find that it's either: North America
General Purpose 2 or Europe General Purpose 3. If you're
working with documents that are primarily destined for the web then
either is perfectly acceptable. However, if you're documents are
destined for print then these settings are generally regarded as being
less than ideal. So, if the General Purpose settings are not
ideal, what is?
I could answer the above question by simply writing
"US or Europe Prepress Defaults", but doing so doesn't
really help explain why nor would it be strictly true. Therefore, I
will work my way through each section of the Color Settings
dialog in turn.
The first section is labelled Settings, and
is a simple pop-up menu with a list of preset Photoshop settings plus
any that you may have saved previously. You needn't worry too much
about this section just yet.
Figure 2
Working Spaces
The next section (figure 3) is labelled Working
Spaces, and as I discussed earlier the selections made here will
determine the Working Space profiles used for color handling of
your documents.
Figure 3 - Default Working Space Profiles
There are four Working Space types in
Photoshop: RGB, CMYK, Gray and Spot (occasionally called
Modes because they appear under the Image>Mode menu). Since configuring
the others follows a similar process I will concentrate on the RGB
Working Space.
Also note that the term Working Space should
not be confused with Workspace, which is used by Adobe to
describe the layout of palettes, menu bars, etc. Working Space
relates specifically to the various color modes available in Photoshop.
RGB - Working Space
Clicking the RGB pop-up menu with the mouse
will produce a list of options similar to that shown below (figure 4).
In this example I've selected Adobe RGB (1998) as the RGB
Working Space. You'll also notice that it appears grouped with five
other Working Spaces, these historically being the most popular choices
of Photoshop professionals.
Typically, sRGB will be confined to situations were the user is
solely interested in web design. ColorMatch RGB was once a
favoured choice of many Mac users and Apple RGB is apparently
for Mac web design. The
P3 Color Space is
an RGB color space that was introduced in 2007 by the SMPTE. The color
space features a color gamut that is much wider than sRGB, and has
recently been adopted by Apple as the color space to which all of their
iOS devices and displays correspond to.
ProPhoto RGB is generally regarded by imaging professionals as the
ideal color space for editing photographic images, and has been my preferred working space for
many years
now. It's a very wide color space that encompasses the entire
range of colors that your likely to encounter. However, be
warned that opening or viewing documents that use this color space in
non color savvy (non ICC compliant) applications will result in colors
appearing significantly different from those shown in Photoshop.
Figure 4
If you look just above the
six common Working Spaces you should also find Monitor RGB. This is
the color space of your monitor as created when it was calibrated. Generally, it isn't a good idea to use the
monitor profile as your Working Space, but it's important that
does appear in the list. Why?
It's often claimed that Photoshop has no obvious way
of informing the user which monitor profile is actually being used.
Well, a quick check for Monitor RGB in the RGB Working Space
pop-up should be enough to put your mind at rest. If Monitor RGB
is showing something other than the profile you created when
calibrating the monitor it is essential that you investigate the reason
and make the appropriate corrections.
CMYK - Working Space
Desktop type inkjet printers from Epson, Canon and
HP actually require RGB data rather than CMYK, which
means that the choice you make for this particular Working Space
will have no influence in their actual output. This is the main reason
that I leave it set at the default US Web Coated (SWOP) v2, and
if using a desktop inkjet, then I suggest that you do likewise.
So, other than the list of available profiles, the
procedure for choosing CMYK Working Space isn't that different
to RGB.
Grayscale - Working Space
With the Grayscale Working Space we have
access to two gamma settings, a series of five preset dot gain curves,
the ColorSync Gray Work Space (Mac only) and the ability to
customise the dot gain to our own requirements. The Gray Gamma 2.2
is probably the best for most users, but feel free to experiment.
Also note, that if you choose to use a Custom
Gamma or Dot Gain this will be the Working Space
listed in the Gray Working Space pop-up menu.
Spot - Working Space
The Spot pop-up menu is broadly similar to
the greyscale, but for spot colors. The options that we find include a
series of five preset Dot Gain options and the facility for
customising the Dot Gain curve if required.
Color Management Policies
Color Management Policies
is very
important feature first introduced by in Photoshop 6. Its importance
continues to this day, which is why I tend to spend so much time trying to
explain the various options. Figure 5 below shows the default
setup, but this hides a lot of important information.
Figure 5 - Photoshop Default Color Management
Policies
Based on feedback, this section of the essay is
probably the one that causes new Photoshop users greatest difficulty.
Nevertheless, it's an important aspect of Photoshop that is better to
understand than ignore. Therefore, the explanation that I give below
will appear quite wordy.
Basically, each Working Space will have the
same set of three policy options, although you need not configure each
identically. The Color Management Policies are: -
(a) Off
In simple terms, the Off Policy ensures that
Photoshop does as little as possible when dealing with ICC profiles. In
most situations it isn't the ideal choice and contrary to popular
believe it's certainly not the panacea for new users that some would
have them believe.
Figure 6 - RGB Color Policy is Off
The following explanation will give you some idea as
to the behaviour of Photoshop when this option is selected.
-
Choosing Off will mean that all new
documents will be created without an embedded ICC profile. Likewise,
when you save them there will be no embedded profile within the
document. Generally, documents that do not contain an embedded ICC
profile are referred to as being untagged, which invariably means
that their color appearance will vary on different monitors and
even within different applications on the same computer.
-
Opening an existing document that contains an embedded ICC
profile that matches the current Working Space means that
Photoshop will honour the embedded profile, and that this profile
will subsequently be saved with the document once you've completed
editing same.
-
The default Pasting behaviour between
documents is to retain numerical values (RGB pixel values), not the
appearance. This means that no conversion between color spaces will
take place and will often lead to the pasted section of the document
taking on a radically different appearance to that of the original.
-
Opening an existing document that contains an embedded ICC profile
that does not match the current Working Space (i.e. profile mismatch)
will cause that embedded profile to be stripped out of the document.
The document will subsequently be saved with no embedded profile.
With this policy you'll find that when the Ask When
Opening warning checkbox is also unchecked a warning similar to that
shown in figure 7 will appear.
Figure 7
The problem with this configuration is that the user
either accepts what Photoshop dictates or doesn't open the document at
all, which isn't much of a choice. Activating the Don't show again
checkbox will ensure that you're no longer nagged by the alert dialog,
but be aware documents that contain an embedded profile that differs
significantly from the current Working Space will generally have a less
than optimal appearance.
(b) Preserve Embedded
Profiles (default - see figure 5 above)
For most situations this policy offers the greatest
degree of flexibility and therefore is to be preferred. The following
explanation should give you an idea as to the behaviour of Photoshop
when this policy is selected.
-
Choosing Preserve Embedded Profiles means
that when you open an existing document into Photoshop that has an
embedded ICC profile that differs from the current Working Space,
then that document and its associated profile will be left intact. In
other words Photoshop will make no attempt to convert the document to
the current Working Space; the original embedded profile will
be retained and subsequently saved with the document. Nevertheless,
even though the document and Photoshop are no longer in sync, color
space wise, the document preview will still be accurate. If you're
unclear as to why this should be then see explanation of document
specific color in Section 1.
-
When opening an existing document with an embedded ICC profile that matches the current Working Space Photoshop
will take no action; the document is opened and saved as normal.
-
The default behaviour when pasting either an RGB
or Grayscale document is slightly more complex whereby the appearance
of the pasted documented will be preserved but the numbers will
change (i.e. the pixel values will change). In the case of CMYK it is
the numbers that will be retained, not the appearance.
-
If the document being opened or imported has no
embedded ICC profile (i.e. the document is untagged) then Photoshop will
use the current Working Space for editing and previewing
purposes. However, the profile will not be embedded into the document
when it is subsequently saved.
-
Creating a new document with this policy setting
means that the current Working Space is used for editing and
previewing. The associated profile will eventually be embedded into
the file when saved. If necessary, the default Working Space
profile for new documents can be overridden in the New
document dialog.
(c) Convert to Working Space
This policy behaves in an almost identical fashion
to Photoshop color management way back in version 5. It's for this reason that some
Photoshop dinosaurs (there are still some around) tend to favour it. Actually, this policy
isn't a bad choice, but it does need to be treated with care.
Figure 8 - RGB Policy is Convert to Working RGB
-
If an existing document with no embedded ICC profile
is opened or imported into Photoshop then the current Working
Space will be used for editing and previewing. However, there
will be no profile embedded into the document when it is saved (i.e.
the resulting document will be untagged).
-
If an document is opened or imported and has an
embedded ICC profile which is found to differ from the current
Working Space then that document will be converted into, and
subsequently saved in the Working Space. When the document and
the Working Space profiles are matched then Photoshop takes no action;
the document is opened and saved as normal. New documents will be
previewed, edited and ultimately saved in the current Working
Space.
-
Finally, the default pasting behaviour is to
convert and thus preserve the appearance of the document. However,
the user will get the option not to convert the pasted document,
hence preserving the numbers if the pasted document doesn't match
with the target document.
With this policy you'll find that, by default, the Ask When
Opening warning checkbox is also unchecked for Profile Mismatches,
so a warning similar to the following (figure 9) will appear. It's worth reading the text and comparing
it with figure 7 above.
Figure 9
At first glance the above warning appears virtually
identical to that shown for the OFF Policy, but there is a
subtle difference - the document is converted to the Working Space
profile rather than discarding the embedded profile. Compare the text
of the two screen shots (i.e. figure 7 and 9) if you're in any doubt as to
the differences. Again you may wish to tick the Don't show again
checkbox so as to stop this warning reappearing in the future.
Overriding the Default Policy
Behaviour
The previous section described how your choice of
Color Management Policy determined the default behaviour of
Photoshop under various scenarios. However, you need not be
confined to these preset outcomes. A much better option would be to
configure the Color Management Policies as shown in figure 10
below.
Figure 10
Above we
can see that each of the checkboxes for Profile Mismatches and Missing
Profiles be set for Ask When Opening or Ask When Pasting.
Basically, the three checkboxes associated with the profile warnings
have the following impact on the Color Management Policies: -
(i) Profile Mismatches: Ask
When Opening
When this checkbox is active Photoshop has been set
to present the user with a warning when the document being opened or
imported has an embedded profile that does not match the current
Working Space. The warning looks like figure 11, and contains three
options with the default settings being dependent upon the actual
Color Management Policy in operation at the time. Noticed that
unlike the examples shown previously, all the necessary information
required to make an informed decision is present.
Figure 11
The above example is preset for how the dialog would
appear when the Color Management Policy is set for Preserve
Embedded Profile. The user can choose to leave the document as is
(default - Use the embedded profile), allow the conversion (Convert
document's colors to the Working Space) or discard the embedded
profile and switch off color management (Discard the embedded
profile). Had the policy been Convert to Working Space the
dialog would have looked almost identical except that it would have
been preset for Convert document's colors to Working Space.
Basically, the answer to the question: How do you want to proceed? is
already decided for you when the Embedded Profile Mismatch
dialog appears. However, if you know this answer to be incorrect then
by all means make an alternative selection, otherwise leave well alone,
and click OK.
I think you will agree that the warning in figure 11
is a lot more user friendly than the one that appears under similar
circumstances when Ask When Opening is unchecked. At least with
this option you now have the opportunity to assign an alternative
profile to the document before it opens.
(ii) Missing Profiles: Ask
When Opening
Choosing this option means that Photoshop has been
set to present the user with a warning when the document being opened has
no embedded ICC profile. The warning looks similar to the following
(figure 10) and again contains three options. The preset or default
selection is dependent upon the Color Management Policy in
operation at the time.
Figure 12
The
above example is preset for how the dialog would appear when the Color
Management Policy is set for Preserve Embedded Profile. Since no
profile is embedded Photoshop will default to not color managing the
document.
The lower Assign Profile (and the associated
and then convert to working RGB) checkbox is the best choice if you
know the true color space of source the document.
(iii) Paste Profile
Mismatches: Ask When Opening
Figure 13 below shows the Paste Profile Mismatch
warning that appears in the event of the color spaces of the two
documents
not matching.
Figure 13
Note that the terms preserve color appearance and
color numbers relate to the source document, not the destination.
The various warning dialog boxes shown above are
only a sample of those that may appear as you open or import documents
that contravene the defined Color Management Policy. However, I
think that the text messages included in each should be more than ample
to explain what each option does and will therefore allow you to make
the appropriate choice.
Conversion Options
Figure
14 shows this section of the Color Settings dialog in its default
configuration.
Figure 14
Engine: this is the name of the engine, which
will be used for all color space conversions. Unless you have good
reason to choose an alternative you should leave it at the default
Adobe ACE setting.
ACE is the direct equivalent of the Built-in
engine used in Photoshop 5. Windows users should not be tempted to
choose ICM. Mac users should keep in mind that the option chosen here
will override the selection made in the ColorSync setup.
Intent: this pop-up menu allows the user to
select from four different rendering intents, namely Perceptual,
Saturation, Relative Colorimetric and Absolute
Colorimetric. Typically, most users will choose between either
Relative Colorimetric or Perceptual. A short description on
each is provided in the Description section of the Color
Settings dialog. A more comprehensive explanation can be found in
the Photoshop on-line help files.
With Relative Colorimetric it is only those
source colors that are out of gamut (i.e. can't be viewed/printed
accurately within the destination color space) that will be mapped to
the closest in-gamut color, the remainder are left unchanged. This
means that in the case of documents containing lots of out-of-gamut
colors the visual relationship between the colors (after conversion)
will almost certainly change. With Perceptual, all colors of the
source color space will be mapped to the nearest in-gamut color of the
destination color space thus maintaining the visual relationship
between colors. In other words, with Perceptual the whole
document color gamut will be compressed so that it fits within the new
color space. The Photoshop default is Relative Colorimetric.
Use Black Point Compensation: this should be
kept checked. Black Point Compensation ensures that the darkest
neutrals of the source color space are mapped to the darkest neutrals
of the destination color space. In most circumstances toggling BPC
ON or OFF will result in no obvious change to the document
appearance, but in some situations converted documents will look/print
horrible if BPC is Off, so be very careful with this setting.
Use Dither (8-bit/channel images): as with
Black Point Compensation this should be kept checked. The
description box at the bottom of the Color Settings dialog box
will give you some clue as to what it does.
Compensate for Scene-referred Profiles: This
option compares video contrast when
converting from scene to output profiles. This option reflects default
color management in After Effects CS4 and later.
Advanced Controls
As with the conversion options, this section will
only be present in the Color Settings dialog if the user chooses
to activate the More Settings option. Figure 15 shows this section of
the Color Settings dialog in its default configuration.
Figure 15
An explanation on what each of these options do is
provided in the Description box and on-line helps files. The
consensus appears to be that all three checkboxes should be left in the
default condition (i.e. Desaturate Monitor Colors... and Blend RGB
Colors... unchecked, and Blend Text Colors... checked).
The Desaturate Monitor Color
option is the one that has greatest potential to cause confusion, as it
causes the document preview to become progressively less
saturated as the percentage is increased. Those choosing to work in
very wide color spaces may find it useful, however, the majority of
Photoshop users should leave it unchecked.
Saving Out Your Own Default
Color Settings
Select the Save button and give your settings
a Name and Description by which you can call them back in
the future, if for some reason you make a temporary change. Also, note
that you can have as many different sets of settings as you wish,
although only one can be active at a time. Figure 16 shows my preferred
color settings.
Figure 16 - Customised Color Settings Configuration
If you're using
other
Adobe Creative Cloud applications you'll
also want to make sure that all color handling within theses
applications is matched with Photoshop. To help you with this task Adobe
has provided a feature within Bridge (Edit menu >
Color Settings) that enables you to synchronise the color settings
for all of the suite applications.
Figure 17 - Synchronise Creative
Cloud Color
Settings
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 and LED technologies. So, if you're still
having problems with dark prints after calibration it's worth reducing
the display brightness control by 10/15%.
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 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
screen shot below shows a typical view of the new
Proof Setup (i.e. Customize Proof Condition) dialog in
CC 2018. 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 is best to keep it checked.
Display Options (On Screen)
There are two options (or checkboxes) shown in this
section of the Customize 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).
When
Simulate Paper Color checkbox is selected the Simulate Black Ink will
be automatically 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). 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
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. I suppose you could say that since it wasn't broken in
earlier versions 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.
It’s 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 profile for a
Nikon film 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 this
is not possible because 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
screen shot 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
The screen shot shown below shows the
Printer Setup and Color
Management sections within Photoshop Print Settings
dialog box. In particular, the Color Management section enables you to
define the Color Handling and Printer Profile options
along with the Rendering Intent used to convert the document between
the document profile and printer profile.
Figure 23 - Print Settings
To the right of the preview image and reading
from top to bottom we have a
Print Setup, which gives access to the printer driver along with options
for positioning and scaling
prints. Pressing the Print Settings button will open your printer
driver dialog thus giving you access to the various settings for color
management, page layout, etc. The actual dialog will differ according
to your OS and printer vendor.
Color Management
is still the default view for the Print dialog, and the preview window
is fully color managed, and includes the ability to soft-proof images. The
actual soft-proofing is controlled by the three checkboxes below the
preview image. These are labelled Match Print Colors, Gamut Warning
and Show Paper White. To keep things simple I will focus on
only those settings that fall within the Color Management
section in figure 23 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:
-
Color Handling - this is the pop-up
menu from which you choose the preferred method of managing
color when printing from within Photoshop. By adopting this approach
Adobe have separated the workflow aspects of printing from the
media choices. There are three color handling options, and each has its own
associated preset configuration within the Print Settings dialog,
thereby helping the user avoid erroneous settings.
-
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.
-
Photoshop Manages Colors - with this
option Photoshop will convert the document to the printer/media
profile 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.
-
Separations - this option is used
when printing CMYK documents where each channel is handled
separately. If your document is RGB the option will be greyed
out.
-
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.
Normal Printing - 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.
The Description box is a useful feature within
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).
For details on how to configure an Epson print
driver in macOS, see my
Printing in Photoshop tutorial. Section 7 - Saving Documents
Save As
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. Notice that the dialog even informs us which profile
is being embedded within the document.
The
screen shot shown below (figure 24) is how the dialog appears in macOS
Big Sur. The Windows dialog looks slightly
different, but is functionally identical to macOS.
Figure 24
Hopefully the material presented in this essay has
been helpful and improved your understanding of Adobe's approach to
managing color in Photoshop. As noted throughout the essay there is
vast body of material to be found all over the internet. A simple
search using 'Google' and the keyword Color Management is all that is required.
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