1. What's all the Fuss About
In truth, and for many, colour management is of no great importance,
but for photographers and anyone else interested in the accurate
reproduction of colour in print or on screen, it is one of the most
vitally important features introduced by Adobe as part of Photoshop 5.
One of the most often raised
issues relating to Photoshop is – "why don’t the printed
colours match the colours displayed on screen?" Epson claim in
one of their online support documents that the answer is quite simple
- "because monitors and printers use different technologies to
create colour". They go on to say - "no monitor will ever
match the printed piece of ANY printer due to the fact that the human
eye perceives colour completely different when looking at colour
reflecting off paper or projection from colour monitors".
However, this is only partially true, by ensuring that Photoshop is
correctly configured it is possible to achieve "acceptably"
accurate colour matched prints with only minimum effort.
This article explains the
process of configuring the colour management system within Photoshop 5
for those aiming to optimise the RGB workflow required for making
prints that come "acceptably" close to matching
their on screen image when using inkjet printers from manufacturers
such as Canon, Epson and Hewlett Packard.
Obviously, in the limited
space available it is not possible to address all the issues
pertaining to colour management. For those wishing to gain a better
understanding of how colour management works within Photoshop 5 you
should follow this link to Adobes On-line Guidance Documents:-
Further information can also be
obtained from Andrew Rodney's web site at:-
The final section of this article
deals with colour correction. Although not strictly speaking anything
to do with colour management, I believe you will find it informative if
2. The Colour-managed Workflow
The purpose of a Colour
Management System (CMS) is to maintain a consistent "appearance"
of any given colour on different devices (i.e.; scanners, monitors,
printers, etc.) throughout our system. In order that we may achieve
this it is first necessary for each device to provide the Photoshop
Colour Matching Engine or Module (CMM) with some information on how
colour behaves within that device, and this is provided through "Device
A typical "Colour-managed
Workflow" will involve image input via a scanner or Photo CD,
being viewed on the monitor, with colour correction of images on the
computer, and image output to a printer or film recorder. As the image
data is passed along the chain - from scanner - to - computer - to -
monitor - and printer, colour inaccuracies will be introduced. These
inaccuracies result primarily from the widely differing colour spaces
or gamut's of each device. To minimise these inaccuracies we must give
the CMS information in the form of device "Profiles" that
describe the colour gamut of each device. Using these profiles the CMS
is provided with information that says for example, "this RGB
image data is from such and such a scanner, which sees colour in this
way", the CMS will then know exactly what colour really looks like on
that scanner. Likewise for our monitor or printer, again with suitable
profiles the CMS will adjust the scanner image data into a form that
the monitor or printer can show accurately.
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 (e.g.
ColorVision Photo/OptiCAL, Praxisoft WiziWYG or Monaco Systems
A Typical Colour Managed
It is also worth pointing out
that whilst most low cost, consumer based film and flatbed scanner
applications are ICC aware they tend to impose sRGB as the "Source"
colour space. This colour space is not ideal for anybody
seriously interested in obtaining high quality prints or film output
from within Photoshop, in so far as its colour gamut is so
limited. Some manufacturers i.e. Nikon, Polaroid and MicroTek allow us to scan and save our images in any
we choose. Unfortunately others make similar claims but in reality the "Source"
colour space is
generally always "sRGB". Furthermore, the image is rarely
if ever "tagged" with a profile of any description, so the
file contains no information relating to the profile upon which it is
3. Monitor Calibration
Having first installed
Photoshop 5 on your computer the next task is to make sure your
monitor is properly calibrated. If the monitor is not correctly
calibrated then we can have no confidence in the on screen colours
being a true representation of the image data. Accurately calibrating
your monitor is also an essential (if not critical) first step in
developing a colour-managed workflow. For real accuracy we would
normally wish to use a specialist hardware device, but these tend to
be expensive. However, Adobe has provided us with an acceptable
software solution for this purpose, namely "Adobe Gamma",
although others are available see (http://www.colorcal.com)
The following information
concerning monitor calibration is applicable only to Windows 98,
Windows 98 Second Edition and Windows 2000. Users of Mac systems may
find the procedure to be identical, but the dialogs will look slightly
"Adobe Gamma" can
be accessed either through the Windows Control Panel Folder or via
Photoshop's Help Menu and selecting "Colour Management".
To be honest I don't like the Help version of accessing Adobe Gamma
since part of the process involves overwriting ALL the hard work of
RGB setup etc. (see later).
"Adobe Gamma" is used
to calibrate your monitor at "System Level" and thus
ensures that unwanted colourcasts associated with your monitor are
eliminated. The profile created as part of the calibration process
becomes the "default profile" for your monitor and is also
available for all other applications that can use ICC profiles. This
new "Custom" profile is generally referred to as your
Space", and is unique to "YOUR" monitor. It is
important to note that:- no matter what software application you are
using, the image on screen is always being viewed in "Monitor
A further point worth
considering is your working environment. Calibrating a monitor during
daytime and using it later in an artificially lit room is pointless,
since your perception of colour in natural light is entirely different
from that in artificial light. So consider carefully how, where and
when you set up your system. A consistent environment is an essential
prerequisite for accurate colour matching.
You should use a neutral
background for the Windows desktop, and all screen savers and power
management features should be turned off (and kept “off”). Allow
at least 30 minutes after first switching on your monitor before
commencing the calibration process. Set the white point of your monitor. 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.
Before we begin the process of
calibrating the monitor check to see if "Adobe Gamma
Loader.Exe" or a short cut to it is in your "Start Up"
Folder. The Windows 98/98SE Start Up folder is nested below the
"windows/start menu/programs/startup" folder.
For Windows 2000 things are a
little more complicated in that the "start up" folder is found deep down
the tree in the "Documents and Settings" folder, and
worse still each user has his/her own set of folders - you'll need to
find it yourself!!!
If after checking you can't
find "Adobe gamma Loader.Exe" in the relevant folder;
then you can make a "Shortcut" to the file, it is
found in the "Program
files/Common Files/Adobe/Calibration" folder (this assumes
Windows based computer).
The following page outlines
the various steps in calibrating your monitor based upon Adobe's
recommended procedure and my own experience.
Step by step monitor
calibration using Adobe Gamma
opening Adobe Gamma I recommend selecting the Step By Step
or (Wizard) option. You should then follow the on screen
Gamma then tells us the profile upon which the subsequent
calibration process will be performed.
Profile selection dialog for Photoshop 5.5
Searching out a
Profile specific to make and model of monitor is to a very
large extent a waste of time, most are pretty awful, so if you
don't have one don't panic.
Normally the first
time you use "Adobe Gamma" the profile
initially offered is the standard "Adobe Monitor
Profile". We don’t have to accept this profile, we
can actually select any monitor profile we want, but
realistically it’s as good a starting point as any. In fact
if you are using Adobe Photoshop V5.5 it is MOST DEFINITELY
the place to start. Without going into unnecessary detail it
is recognised that many manufacturer based monitor profiles
are incompatible with the Photoshop 5.5 version of Adobe
Gamma. In fact this is one of the reasons underlying some
people finding it virtually impossible to get a good
screen-to- print match. If you have a version
of Photoshop prior to V5.5 then the problem with Adobe Gamma
and manufacturer supplied profiles shouldn't be a problem.
Windows 98 and 98
Second Edition - folder named windows/system/color
Windows 2000 -
sub-folder named system32/spool/drivers/color
Mac - ColorSync
profiles are located in the System Folder/ColorSync Profiles
The dialog window shown above is unique to Photoshop 5.5 in
that earlier versions don't have the "Description"
window. This new window is actually quite important in that
you can edit the monitor profile name. In fact I recommend
that you do precisely that, otherwise the name shown will stay
with the profile and cause you utter confusion next time open
the Photoshop (e.g. - "Photoshop my profile says
its sRGB, but I know it isn't"). Simply type the new name for your monitor
profile and then select "Next".
If you have already
calibrated your monitor using a manufacturer based ICM profile
and would prefer to recalibrate
using the above method then simply remove the old monitor
profile from the relevant location as indicated below:-
The amount of adjustment required in the
steps that follow will vary, depending upon how far your
monitors’ actual behavior deviates from this initial