This article will explain the main changes and
make suggestions as to how the new Photoshop 6 colour management system
should be configured. The reader shouldn't consider my preferences as
"the best", just a base point from which to begin the
process. However, careful reading should give some clues as to why I
made certain choices. A printer friendly version of this article can be downloaded by selecting
the following Icon
Tutorial Index
To jump to a specific page simply click the underlined text
Pages 1 to 3 Introduction and Monitor calibration
Pages 4 to 5 Photoshop colour
settings
Page 6 Colour
Management Policies, Conversion Options and Advanced Settings
Pages 7 to 9 Soft Proofing and
Printing
Page 10 Assign
Profile, Convert to Profile and Saving Files.
Colour Management Primer
Typically each Device will reproduce colour differently, so
that the
colour we see at one stage of the imaging process will rarely if ever
match the colour seen at the next stage. In other words, colour is Device-dependent. The purpose of a Colour Management System (CMS) is to maintain
a consistent "appearance" of colour on different
devices (i.e. scanners, monitors, printers, etc.) throughout our system.
A colour managed system will comprise three basic components, namely:
-
- A device-independent colour space. Usually referred to as the
Working Space or Reference Colour Space.
- ICC/ColorSync profiles for each device (printer, scanner, monitor,
digital camera, etc.) that describes the characteristics of the
device.
- A Colour Matching Module (CMM) that will interpret the information
contained within device profiles and carries out their instructions
on what way the colour gamut of each device should be treated.
A typical "Colour-managed Workflow" will involve the image data
being passed along the chain
- from scanner - to - computer - to - monitor - and printer (see the
diagram below). To minimise the colour discrepancies that result primarily from the widely
differing colour spaces of each device we must give the CMM information in the form of device
"Profiles"
that accurately describe the colour gamut of each device. Most devices are supplied with
generic or "Canned" profiles that describe them pretty well,
but for truly accurate colour matching you should seriously consider
either getting "Customised" profiles for each device done
professionally or buying your own profiling software. I identify 3
companies who specialise in this business area later.
It is also worth pointing out
that whilst most low cost, consumer based film and flatbed scanner
applications are ICC/ColorSync aware they tend to impose sRGB as the
"Source"
colour space. This colour space is inappropriate for high quality
image editing where print or film output is required. Some manufacturers e.g. Nikon, Polaroid and MicroTek allow us to scan and save our images in any ìDestinationî
colour space
we choose. Unfortunately others make similar claims but in reality the
"Destination" colour space is
generally always "sRGB". Furthermore, the image is rarely
if ever delivered into Photoshop with an embedded profile (i.e. "tagged").
The new Assign Profile command introduced with Photoshop 6 will
help overcome some of the problems this issue causes.
In with the New
Leaving aside (for the moment) the interface changes associated with
configuring the Photoshop colour management system we find that the
biggest and most far reaching change is; support for "document/image
specific" colour. In Photoshop 5, it is the Working Space that
defines how all the open images are displayed. Therefore, in order that
we can preview the image accurately it must be in the same Working Space
as is defined in the Photoshop 5 "RGB Setup" dialog.
However, with Photoshop 6, the Working Space defined in Color
Settings only really has a
bearing on three types of image, viz.: -
-
new images/documents;
-
existing images/documents without an embedded profile;
and
-
images/documents
with no embedded ICC/ColorSync profile (i.e. "untagged
images/documents" typically form digital cameras and
low end scanners, etc.).
"Image specific" colour means that it's the profile
embedded within an image that determines how the image will be displayed
and not the Photoshop Working Space. With Photoshop 6 we can have
multiple images, each in its own unique Working Space open at the same time
and each will be displayed accurately (of course this assumes a well
calibrated and profiled monitor).
Another important change that users will quickly find is the absence
of the "Display Using Monitor Compensation" checkbox.
It's not that Adobe have removed the feature from Photoshop,
but that they have configured it so that users can't easily turn it off,
well not so as you find it easily, but I'll explain that workaround
later.
Also note that a few new commands have been introduced, namely "Assign
Profile", "Convert to Profile" and "Proof
Setup". The first two are
accessed from the "Image > Mode" menu, and the last
from the "View Menu". I will
discuss each of them in detail later.
I could go on at length waffling about each an every feature change,
but I think it better that I leave such explanations to those who really
understand Photoshop 6 colour management, namely Andrew Rodney
and Chris Murphy. Their
material can be read at http://www.digitaldog.net
and http://www.colorremedies.com
respectively.
Please note that except for the obvious interface differences;
Photoshop 6 for the Mac and PC share a virtually identical set of
features. Therefore, the Mac OS based screen grabs shown below should be
very useful to PC users. Of course there will always be those that look
totally different, but so far as this article is concerned they are
confined to printing and saving your images.
Part 1 - Monitor Calibration and
Characterisation
On opening Photoshop 5 for the very first time users were provided
with the "configure the colour management system"
wizard, but such luxuries are not present in Photoshop 6. This means
that the new user is already at a distinct disadvantage.
Nevertheless, we can make a start on our own by first calibrating and
characterising the monitor. This can be achieved by using the now
familiar Adobe Gamma utility.
Adobe
Gamma is a "Control Panel" utility that can be accessed
from the "Apple Menu > Control Panels" on the Mac
and "My Computer > Control Panel" on the PC. Before
running Adobe Gamma,
-
it is best that your monitor has been switched on
for at least 30 minutes;
-
work in subdued lighting when calibrating
a monitor using Adobe Gamma; and
-
set the white point of your monitor.
Typically it will be set for 9300oK, which is far too blue
for our purposes. This is a hardware adjustment, and how you do it depends on the monitor you are using. Most monitors have a control panel. If you're unsure how to set the white point on your monitor, consult the documentation that came with it.
Another
good tip is to set your "Desktop
Colour" to grey. Mac users can do this via the "Apple
Menu > Control Panels" and then choosing
"Appearance". Windows users should choose "Start
> Settings > Control Panel" and then "Display".
Using Adobe Gamma is pretty straight forward, but I've included a
few more tips along with the screen grabs.
Step 1
When the Adobe Gamma utility is first opened you will be asked to
make a choice between the "Assistant" and the "Control
Panel" method. It's probably easier to use the "Step by
Step Assistant" method.
Step 2
Choose your monitor profile or pick one that's close. If in doubt
choose the Adobe default monitor profile or even sRGB, it really
makes little difference since all we are doing is defining the start
point.
Before progressing to the next step, be sure to give the profile a
unique description and include the date.
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