Photoshop 7

Colour Settings


By Ian Lyons

A Computer Darkroom Review

The eagerly awaited Photoshop 7 is now with us and we find that Adobe has made a few minor but important changes to colour management. This essay will explain these changes and also make suggestions as to how the Photoshop 7 colour management system should be configured, although the reader shouldn't consider my preferences "the best", just a base point from which to begin the process.


Colour Management Primer

Ever since the beginning of colour reproduction, colour management has existed in one form or another. The basic concept underlying Colour Management is to ensure that colour data is processed in a consistent and predictable way throughout the entire imaging workflow. A typical Imaging System will consist a wide range of Input and Output Devices, and each device will reproduce colour differently. This means that a colour represented by one device will rarely if ever match the same colour represented on another device. In other words, colour is Device-dependent. So expanding upon our earlier definition we can say that the purpose of a Colour Management System (CMS) is to maintain the consistent and accurate "appearance" of a colour on different devices (e.g. scanners, monitors, printers, etc.) throughout our imaging workflow.

Components of a Colour Management System

In order that we can achieve the above aims a colour managed system will require three basic components, namely: -

  • A device-independent colour space - this is usually referred to as the Working Space or Reference Colour Space.

  • ICC/ColorSync device profiles for each device (printer, scanner, monitor, digital camera, etc.) that describe the colour characteristics of the specific device.

  • A Colour Matching Module (CMM) that will interpret the information contained within a device profile and carry out the instructions on the way the colour gamut of each device should be treated.

The following diagram demonstrates a typical "colour-managed workflow" and shows the image being passed along the chain - from scanner/digital camera - to - computer - to - monitor - and printer with the ICC profiles ensuring that the colour data from/to each device is correctly described.


Colour Numbers, their Meaning, and Profiles

A digital image will comprise pixels each of which is represented by a number. This number will describe the location of the pixel within the image and its particular colour value (typically an RGB value). We have already noted that since colour is device-dependent the "appearance" of each coloured pixel will vary for each device. We also noted that this is because each device has its own unique way of translating the raw colour value into visual colour. To minimise the discrepancies that result from the widely differing colour characteristics of each device we use the device profiles to inform the CMM how the colour values produced by that device should actually appear. This may be on our monitor, in print or on film output. In simple terms it is the device profile that conveys the "meaning" of the raw colour numbers associated with each pixel.

Whilst "Consumer "class film and flatbed scanner software applications are now ICC/ColorSync aware they tend to be based upon sRGB, likewise consumer digital cameras. This colour space is not normally regarded as appropriate for high quality image editing, especially when print or film output is required, but is quite often all we can expect to get. We should not confuse matters by assuming that the scanner or digital camera is an sRGB/Adobe RGB device - they most certainly aren't. The fact that the image delivered into Photoshop by the scanner or digital camera application software is already in a device-independent colour space means that it has already undergone a considerable amount of data processing.

Some digital hardware vendors allow scanning/capture of images in any user selected "working space" colour space. Unfortunately, the image is rarely delivered into Photoshop with an embedded ICC/ColorSync profile, which can lead to confusion and error.

Device profiles come in two basic forms, i.e. "Input" and "Output". Input profiles typically describe the colour 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 it is only possible to select them as the "Source" meaning we can never convert an image into the colour space of our scanner or digital camera. Output profiles are two-way meaning we can convert "From" or "To" them.

Many "Prosumer" class scanners and digital printers are now supplied with some form of generic or "canned" profiles. Whilst these profiles are useable they are rarely accurate.  For truly accurate colour matching you should seriously consider getting "Customised" profiles for each device and/or media type. These profiles can be created professionally or by buying your own profiling software. Sadly very few, if any digital camera vendors have adopted the "canned" profile approach instead opting process the images into a device-independent colour space as discussed above.

Why bother with Profiles?

Even though colour correction and colour management are not the same thing they are often confused with each other, especially by the novice Photoshop user. The colour characteristics of most imaging devices are such that it is very rare for them to be truly linear (i.e. R=G=B=Neutral). Sometimes this characteristic is referred to as the device "not being well-behaved". Scanners and printers are good examples of "badly behaved" devices. Obviously it would be extremely difficult for a Photoshop user to edit an image where a group of pixels with values of R=G=B=128 (grey) actually "appeared" to be non-neutral. In such circumstances colour correction would be an absolute nightmare. To overcome these discrepancies we usually carry out all our editing in a colour space that is well-behaved. Well behaved colour spaces are more usually referred to as the "working space", and are always characterised by having R=G=B appearing neutral. Without the aid of accurate device profiles the accurate translation of the raw colour data (the numbers) from our scanner/digital camera into the working space will prove very difficult, if not impossible. The translation from the working space into the media specific colour space of a digital printer will prove equally difficult without the aid of media specific printer profiles.

So the benefit offered by colour management is that the process of colour correction can be undertaken by the user in the knowledge that the image displayed on their monitor is an accurate visual representation of the original subject, and that the final print will accurately reflect the colours of the displayed image.

What changes have been made to colour management?

 "EXIF" is a familiar term to many digital camera users, but until Photoshop 7 it had little use. EXIF is a standardised format agreed by various digital camera vendors for incorporating data such as the exposure time, aperture, lens, picture resolution, colour space, etc into the image file. However, Photoshop 7 now reads the EXIF information embedded within the JPEG format images captured by digital cameras and can also write new information to the EXIF file. There are a number of quirks in the way Photoshop 7 manages the colour space of these image files, and so those already familiar with Photoshop 6 should be prepared for a few surprises.

The screenshot below is presented for those readers who've never seen EXIF data before. I captured the information file from the new File Browser window but you can also get it by selecting "File Info > EXIF" from the Photoshop File menu.


So far as colour management and Photoshop 7 are concerned EXIF holds some useful information (circled red in the screenshot), and this information. The first piece of  information is the potential availability of an embedded "Colour profile" that describes the actual colour space of the image. The second is the EXIF "Colour space" to be assumed in the event of no colour profile being embedded. The embedded colour profile can be anything the camera vendor chooses to allow or nothing at all. At time of writing this essay it appears that only Nikon have chosen to allow embedding of colour profiles, and so many users will never see an embedded profile. On the other hand the EXIF colour space appears to be widely used.

It is worth noting that the EXIF colour space recorded within the EXIF information can only be one of two values, i.e. sRGB or Uncalibrated. Generally digital camera manufacturers have set their software to automatically write sRGB as the EXIF colour space. This means that in the absence of an embedded colour profile Photoshop 7 will attempt to open JPEG format digital camera images into the sRGB colour space. If the EXIF colour space has been set to Uncalibrated Photoshop will rightly assume that the image has no predefined colour space information and the image will not be colour managed (the image will be defined as Untagged RGB).

The screenshot shows the EXIF file for a JPEG image captured on a Nikon D1X digital SLR camera. The owner had configured the camera software to output the image in Adobe RGB and as we can see the Nikon software has been very obliging and embedded the Adobe RGB colour profile. Prior to Photoshop 7 this colour profile could not be read and so the image would have opened with the "Missing Profile" dialog flagging a potential problem - not anymore! The image will now open directly into Photoshop or present the user with a "Profile Mismatch" warning! Note: Each of these terms will be discussed in Part 2 of this essay.

Also notice that the screenshot shows the EXIF colour space is set for sRGB - so we have an image with two conflicting sets of colour space information. Thankfully Adobe has coded Photoshop 7 to give priority to the colour profile and when it's not present Photoshop will use the EXIF colour space information.

2 September 2002

It appears that some users were getting confused with the appearance of the Profile Mismatch dialog so in late August Adobe released a Plug-in designed to make Photoshop 7 behave in the same way as earlier versions, and so ignore the presence of the EXIF colour space information. The new plug-in is called Ignore EXIF Colour Space and can be downloaded from:

PC platform - http://www.adobe.com/support/downloads/detail.jsp?ftpID=1881

Mac platform - http://www.adobe.com/support/downloads/detail.jsp?ftpID=1882

Some Photoshop Revision!

Photoshop 7 continues to use document/image specific colour settings, which means that the colour space of each document is independent of others that may be open on the Photoshop desktop. As with Photoshop 6, the working space defined in "Colour Settings" only has a bearing on three types of image, viz.: -

  1. new images/documents;

  2. existing images/documents without an embedded profile; and

  3. images/documents with no embedded ICC/ColorSync profile (i.e. "untagged images/documents").

"Image specific" colour means that it's the profile embedded within an image that determines how the image will be displayed (it's appearance) and not the Photoshop working space. With Photoshop 7 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 monitor).

Note that the "Assign Profile", "Convert to Profile" and "Proof Setup" commands have undergone minor alteration. I will discuss each of them in detail later.

Also note that except for the obvious difference in user interfaces; Photoshop 7 for Mac OS9.x, Mac OSX and Windows share a virtually identical feature set. Therefore the Windows based screen shots that follow should be equally useful to Mac users.

Part 1 - Monitor Calibration and Characterisation

On opening Photoshop 7 for the very first time we are presented with an information dialog (shown below). The purpose of this dialog is to warn the user that the Photoshop "Colour Settings" will be automatically configured or to provide access for manual setup. As with Photoshop 6 and unlike Photoshop 5 and 5.5 there is no "wizard" to help the user through the process of configuring the "Colour Settings". If Photoshop 6 is anything to go by many new users will panic at this dialog and accept the defaults only to realise later that this was only a short-term solution.


For the purpose of this essay I to have chosen the "No" option and have therefore accepted the default Photoshop settings. However, I chose this option for no other reason than to concentrate upon monitor calibration and characterisation. Once I have discussed calibrating the monitor we can return to colour settings.


Accurately calibrating and characterising the monitor is a critical element for any colour-managed workflow. Our aim is to calibrate the monitor at system level so that we can eliminate unwanted colour casts from the monitor, and so obtain the best possible display  environment for editing our images. We also need to characterise the monitor by means of an ICC device profile. This profile is simply a file that includes a description of the characteristics of your monitor. The monitor profile will then be used by Photoshop to compensate for the monitor's colour-display limitations. Photoshop optimises the display of images using the image/document profile (e.g. Adobe RGB, sRGB, ColorMatch), and the monitor profile.

Adobe no longer installs Adobe Gamma with the Mac version of Photoshop, however, Mac OS9.x or OSX users can use the Monitor Calibrator supplied as part of ColorSync or copy Adobe Gamma from the Photoshop installation CD. The Monitor Calibrator utility operates in a similar fashion to Adobe Gamma and so I'll not bother describing it here.

To calibrate and characterise the monitor Windows users should open the "Adobe Gamma" utility or a third party alternative. For many new users Adobe Gamma is more than sufficient and it's free.

Adobe Gamma is a "Control Panel" utility that is accessed from the "My Computer > Control Panel". Before running Adobe Gamma, it is best that the monitor has been switched on for at least 30 minutes. It is also best to work in subdued lighting when calibrating a monitor using Adobe Gamma. Another good tip is to set the "Desktop Colour" to grey.

Step 1

When the Adobe Gamma utility is first opened you will be asked to make a choice between the "Step- by- Step (Wizard)" and the "Control Panel" method. It's probably easier to use the "Step-by-Step (Wizard)" method.


Step 2

Using the Load button 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 (my example shows Mitsubishi Diamond 31/3/02).

Step 3

Set your monitor contrast control to maximum and then adjust the brightness control until the innermost grey square is only just visible against the black surround. Squinting your eyes helps with this process, as does keeping the room lighting at a low level or off.


Step 4 

If you're using a manufacturer supplied profile for your specific make and model of monitor then in all probability the Phosphors will be listed as "Custom". If this is the case leave well alone. If you don't have a monitor profile choose either Trinitron or P22-EBU. I keep getting asked -"how do I decide which is appropriate for my monitor?"  You can tell a Trinitron monitor by simply looking at the display area. A Trinitron type monitor will have two faint lines running across the display area approximately 1/4 from the top and 1/4 from the bottom. If your monitor has these lines choose Trinitron, otherwise choose P22-EBU.


Step 5

Begin by keeping the "View Single Gamma" selected. However, keep in mind that this option "ONLY" allows you to adjust the relative brightness of the monitor.

Adjust the slider until the inner grey square blends with the outer frame, squinting slightly can help. Finally, deselect the "View Single Gamma" checkbox.


Step 6

This is the step where we neutralise the colour imbalances inherent in our monitor. Adjust each of the sliders in turn so as to blend the inner square with its coloured surround. Again squinting is a great help.

Green is usually the most difficult to get right, but persevere. The closer you get to a perfect match at this point the more accurate your final profile will be.


Step 7

Depending upon your computer type choose either the "Windows Default" or "Mac Default" gamma. In reality, this choice is not as important as it once was and you can choose either in the knowledge that Photoshop will make the appropriate corrections when necessary. Personally, and even though most of my work is now done on the Mac platform I choose gamma 2.2


Step 8

Choosing the "White Point" for your monitor is pretty much a formality these days. Even the die-hards are in agreement that 6500oK is probably the best option on most systems.

You should have already set the Hardware white point via the dials/buttons on the monitor. Most monitors have a native white of 9300oK; so do check what it has been manually set to.

Choosing 6500oK provides the cleanest and brightest white point and closely matches daylight. If you feel really confident you could select the "Measure" option. You can choose 5000oK, but this usually produces a slightly dimmer and more yellow white point.


Step 9

Generally, it's better to leave the Adjusted White Point setting at the default - "Same as Hardware". Nevertheless, this option is used to choose a working white point for monitor if it differs from the hardware white point set in the last step.

By way of example; if your hardware white point can only be set to 6500oK, but you want to set it at 5000oK because that most closely represents the environment in which it will normally be viewed, you can set your Adjusted White Point to 5000oK, and Adobe Gamma will change the monitor display accordingly: However, choosing this approach will all cause the graphics card colour LUT to be adjusted quite severely, and depending upon the graphics card the screen can look quite ugly on some systems. As indicated above I recommend that you choose "Same as Hardware" and thus avoid this problem.


Step 10

That's it, if all has gone well you will have adjusted the brightness, contrast and colour settings of your monitor to the optimum values.

Make a quick check using the "Before" and "After" radio button. If you're happy that the screen display now looks more neutral than before press the "Finish" button and "Save" the profile. Once saved the profile will be available for use by the OS and Photoshop.


There are a number of third party alternatives to Adobe Gamma, which can be purchased from companies such as Color Vision and Xrite

The advantage of Adobe Gamma (Windows systems) and Monitor Calibrator (Mac systems) is that they're free, whereas the third party products can cost nearly as much as Photoshop. However, since many third party alternatives use "hardware" and not the "eyeball" for measurement we are assured of greater accuracy.

Useful Information on location of  ICC/ColorSync Profiles

Profile locations:

Windows 98, 98 Second Edition and Me - folder named windows/system/color

Windows 2000 and  XP - sub-folder named system32/spool/drivers/color

Mac OS9.x - ColorSync profiles are located in the System Folder/ColorSync Profiles folder

Mac OSX - ColorSync profiles are located in the Library/ColorSync/Profiles folder

Part 2 - Photoshop 7 Colour Settings

Now begins the process of configuring Photoshop. This is achieved through the "Colour Settings" dialog found under the "Edit" menu (Windows and Mac OS9.x) or the Photoshop menu (Mac OSX).

The  "Colour Settings" dialog is the control room for the Photoshop 7 colour management system, and like all control rooms it's complicated. The default setting is "Web Graphics Default", but this is certainly not the best choice.

I will work my way through each section of the "Colour Settings" dialog in turn. Note the "Description" box at the bottom of the dialog. 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 checkbox labelled "Advanced Mode", it's probably best that you select it now. At least that way you will see everything that the "Colour Settings" has to offer, even if some are only applicable to the most advanced of Photoshop users.


The first section is labelled "Settings"; this is simply a pop-up menu with a list of pre-set Photoshop settings, plus any that you may have saved. You need not worry too much about this section just yet.



If you are upgrading from Photoshop 6 it is simply a matter of selecting the your previous setup. Notice that Adobe has retained the "Colour Management Off" option for those users who find the whole subject much too complicated. Although I don't recommend choosing this option I am aware that quite a few new Photoshop users working on the PC Windows platform find it easiest to handle. 

Working Spaces

The next section is labelled "Working Spaces", and as I discussed earlier it will determine the working space of certain images (namely the 3 types I mentioned in Part 1).


There are four types of working space in Photoshop, RGB, CMYK, Grey and Spot. For the purposes of this exercise I will concentrate mainly on the RGB colour space, since configuring the others follow a similar process.

RGB - Working Space

Clicking the RGB pop-up menu with the mouse will produce a list of options similar to that shown below. I chose "Adobe RGB (1998)" because it's the working space I settled on when using Photoshop 5. Notice that Adobe RGB (1998) appears within a group of four working spaces, each of which is device-independent, and in common use with a wide range of Photoshop users. Typically "sRGB" will be confined to those users solely interested in web design, "ColorMatch" is a favoured choice of many Mac users and "AppleRGB" is apparently for Mac web design.


Notice that just above the four common working spaces we also find options for "Monitor RGB" (green spot in the screenshot), and in the case of Mac systems "ColorSync RGB". "Monitor RGB" is simply the colour space of your monitor as created by the Adobe Gamma utility (or a 3rd party software/hardware combination).

Unlike version 5 Photoshop 6 and 7 have no out-front way of informing the user, which monitor profile is actually being used. However, 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.  It is also possible to select your monitor space as the Photoshop working space, but this is not really a good idea. "ColorSync RGB" is only available to Mac users and will reflect the settings chosen as part of the ColorSync setup.

The actual list of options available for selection as working spaces differs depending on whether you activated Advanced Mode, or not. If you chose to activate Advanced Mode then the list of available RGB profiles will be quite extensive.

If you had previously been using another working space such as "BruceRGB" then it should also appear as one of the options in this extended list. If it doesn't  you can still create it yourself by choosing "Custom" (yellow spot in the above screenshot). The dialog below appears and you simply type in the data as shown for the Primaries etc, remember to give this new working space a name and click "OK".

Bruce RGB

CMYK - Working Space

Making your choice of CMYK working space isn't that different to RGB except of the list of available colour profiles are rather different. Again, having "Advanced Mode" activated gives us a more extensive list. Since desktop inkjet printers from Epson, Canon and HP actually require RGB data rather than CMYK and so configuring this particular working space will have little or no influence in their actual workflow.


As mentioned above, the choice for you make is pretty much irrelevant if using a consumer class inkjet printer. In my case I just picked US. Web Coated (SWOP) V2. We can  also have pick the old Photoshop 4 or 5 default CMYK options, the ColorSync settings (Mac only), or even customise our own settings.

Greyscale - Working Space

With the Greyscale working space  we have access to two gamma settings, a series of five pre-set dot gain curves, the ColorSync "Grey Work Space" (Mac only) and the ability to customise the dot gain to our own requirements. This latter option is of particular significance to users of Jon Cones Piezography Black and White printing system (discussed in a separate essay). The screenshots below show the various options and a typical customised "Dot Gain" curve.


Please note that if you choose to use a "Custom Gamma" or "Dot Gain" this will be the working space listed in the Grey working space pop-up menu.


A  very important point regarding Greyscale is that it is not tied to the CMYK setup! This is why some legacy greyscale documents might not look quite the same as they did in Photoshop 5.x

Spot - Working Space

The Spot pop-up menu is broadly similar to the greyscale. The options that we find include a series of five pre-set "dot gain" options and the facility for customising the "dot gain" curve if required. In my case I simply selected the standard 20% option.

Colour Management Policies

Colour Management Policies was a new phrase introduced by Adobe with Photoshop 6 and continues virtually unchanged in Photoshop 7. The screenshot below shows a typical setup, but this hides a lot of important information.


This section is probably the one that will cause most new Photoshop  users the greatest difficulty and for that reason the explanation that I give below will appear quite wordy, but don't be put off.

The area zoned in blue in the above screenshot is VERY important and I highly recommend that you make the same choices for Profile Mismatch and Missing Profiles as I have shown above. I usually refer to these particular selections as my "safety net", you'll see why shortly.

Basically each working space will have the same set of three options, although we need not configure each identically. These options are called Policies and include: -

(a) Off

In really simple terms, the "Off" Policy ensures that Photoshop does as little as possible when dealing with profiles. In most circumstances, it isn't a good choice and certainly not the choice to be made by new users. The following will give you some idea as to the default behaviour when this choice of policy is made.

  • Choosing "Off" will ensure that NEW images/documents will (by default) be saved without an embedded profile.

  • On opening an image with an embedded profile that matches the current working space, it will be retained and subsequently saved with the image.

  • The default Pasting behaviour between images is to retain numerical values (RGB pixel values), not the appearance. This means that no conversion between colour spaces will take place.

  • Opening an existing image that has an embedded profile that does not match the current working space (profile mismatch) will cause that embedded profile to be stripped out of the file. The image will subsequently be saved with no embedded profile. The following warning dialog will appear if Ask When Opening has not been activated for Profile Mismatches


The problem with this configuration as compared to the one I recommended in the "Blue Zone" above is that the user either accepts what Photoshop dictates or doesn't open the image at all, not much of a choice. To me this choice is akin to the novice high wire walker operating without a "safety net", stay on the wire or fall off and break their neck! There are always exceptions-to-the-rule and I will later identify one that I find to be essential.

(b) Preserve Embedded Profiles

For most situations this is my preferred choice of colour management policy since it offers the greatest degree of flexibility, assuming the safety net mentioned above is in place. The following should give you an idea as to the default behaviour of Photoshop when this choice of policy is made.

  • Choosing "Preserve Embedded Profiles" will ensure that when an image is opened into Photoshop and is found to have an embedded profile that differs from the current Photoshop working space, then that image and its associated profile will be left intact. By default, Photoshop will make no attempt to convert the image to the current working space; the original embedded profile will be retained and subsequently saved with the image. Nevertheless, even though the image and Photoshop are no longer in sync, colour space wise, the image preview will be accurate.

  • When the image and the working space are matched Photoshop will take no action; the image is opened and saved as normal.

  • The default behaviour when Pasting either an RGB or Greyscale image is slightly more complex; whereby the appearance of the pasted image will be preserved but the numbers will change (the pixel values will change). In the case of CMYK it is the numbers that will be retained, not the appearance.

  • If the image being opened or imported has no embedded profile then Photoshop will use the current working space for editing and previewing purposes, however, the profile will NOT be embedded into the image when it is subsequently saved.

  • Creating a new document with this policy setting will mean that the current working space is used for editing, previewing and the associated profile will eventually be embedded into the file when saved.

The following dialog will appear if Ask When Opening has not been activated for Profile Mismatches. Again, my earlier comment about Photoshop imposing its will on proceedings applies.


At first glance the above dialog appears virtually identical to that shown for the OFF Policy, but there is a subtle difference - the profile is retained rather than discarded.

(c) Convert to Working Space

This policy behaves in an almost identical fashion to Photoshop 5. It's for this reason that many still tend to favour it. Actually this policy isn't a bad choice but does need to be treated with care.

By default, if an image with no embedded profile is opened or imported into Photoshop then the current working space will be used for editing and previewing, however, upon saving the image no profile will be embedded. Photoshop will denote the image colour space as "Untagged RGB"

If an image is opened or imported and has an embedded profile which is found to differ from the current working space then that image will be converted into, and subsequently saved in the working space. When the image and the working space are matched then Photoshop takes no action; the image is opened and saved as normal. Newly created images will be edited, previewed and ultimately saved in the current working space.

Finally, the default pasting behaviour is to convert and thus preserve the appearance of the image. However, the user will get the option not to convert the pasted image, hence preserving the numbers if the pasted image doesn't match with the target image.

Overriding the Default Policy Behaviour

The previous section described how our choice of Colour Management Policy determined the default behaviour of Photoshop 7 under various scenarios. However, we need not be confined to these pre-set outcomes. At the beginning of the previous section I recommended that each of the "checkboxes" for Profile Mismatches and Missing Profiles be set for Ask When Opening or Ask When Pasting as appropriate. It is only through setting these checkboxes to "ON" that we can enable the default behaviour override facility. Furthermore, it is only by setting these checkboxes to "ON" that we can activate the "safety net".

Basically the three checkboxes have the following impact on the Colour Management Policies: -

(i) Profile Mismatches: Ask When Opening

Photoshop has been set to present the user with a dialog box when the image being opened or imported has an embedded profile that does NOT match the current working space. The dialog box looks like the following and contains three options; the pre-set selection is dependent upon the Colour Management Policy in operation at the time. Noticed that all the necessary information required to make an informed decision is present.


The above example is pre-set for how the dialog would appear when the Colour Management Policy is set for Preserve Embedded Profile. The user may now choose to leave the image as is, allow the conversion or strip out the embedded profile and switch off colour management. Had the policy been Convert to Working Space  the dialog would have looked almost identical except that it would have been pre-set for "Convert document's colors to working space".

I think you will agree that the above dialog is a lot more user friendly than the one that appeared under similar circumstances when Ask When Opening was "unchecked". At least we now have the opportunity to assign an alternative profile to the image before it opens.


Now that Photoshop can read the EXIF colour space information it's likely that many digital camera users will be seeing this particular dialog on a regular basis. Since no benefit will be gained by converting the image the best choice in such circumstances is to leave the default  "Use the Embedded Profile"  rather than be temped to choose "Convert document's colours to working space".

Users of cameras such as the Canon EOS 1D and Nikon D1X/H may have programmed the camera to process the images into the Adobe RGB (1998) colour space and will therefore know that the above warning is incorrect. In such circumstances they should choose to either accept the embedded profile or discard it, but they must then use the Assign Profile command to assign the correct profile. Both methods are equally valid. Remember Assign Profile does NOT change the image file only its appearance. Assign Profile and Convert to Profile are discussed on page 8.

If you have a custom profile for your digital camera you should follow the same workflow described for the 1D and D1X/H, but substitute your custom profile in for Adobe RGB (1998).

(ii) Missing Profiles: Ask When Opening

Photoshop has been set to present the user with a dialog box when the image being opened has no embedded profile. The dialog box looks similar to the following and again contains three options; the pre-set selection is dependent upon the Colour Management Policy in operation at the time.


The above example is pre-set for how the dialog would appear when the Colour Management Policy is set for Preserve Embedded Profile. Since no profile is embedded Photoshop will try to assign the working space profile to the image. No conversion takes place, just the assignment of the working space profile.

The lower "Assign Profile (and the associated and then convert to working RGB)" checkbox is the best choice if you know the source images' true colour space and you want the image to appear in Photoshop. Typically, this option will be used for images from a digital camera or similar device that does not embed a profile in the image file or provide EXIF colour space information. Note that the source profile MUST be known and available to the user before this option can be selected.

(iii) Paste Profile Mismatches: Ask When Opening

The screenshot below shows the "Paste Profile Mismatch" dialog that will appear in the event of the colour spaces of the two images not matching.


Note that the terms preserve "colour appearance" and "colour numbers" relate to the source image, not the destination.

The various dialogs that have been shown above are only a sample of those that may appear as you open or import images that contravene the defined Colour 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

This section will only be present in the Colour Settings dialog if the user chooses to activate the Advanced "checkbox". The screen grab below shows this section of the Colour Settings dialog in its default configuration.


Engine: this is the name of the engine, which will be used for all colour space conversions. Unless you have good reason to choose an alternative your 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. Choosing the ColorSync engine is for Mac users as a bad a choice as Windows users choosing ICM

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 the default 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 colours that are out of gamut (i.e. can't be viewed/printed accurately within the destination colour space) that will be mapped to the closest in-gamut colour, the remainder are left unchanged. This means that in the case of images with lots of out-of-gamut colours the visual relationship between the colours (after conversion) will almost certainly change. With Perceptual, all colours of the source colour space will be mapped to the nearest in-gamut colour of the destination colour space thus maintaining the visual relationship between colours. In other words, with Perceptual the whole image colour gamut will be compressed so that it fits within the new colour space. The Photoshop default and recommendation is Relative Colorimetric and after considerable experimentation I have decided to go with Adobes recommendation.

Use Black Point Compensation: this should be kept "checked". Black Point Compensation ensures that the darkest neutrals of the source colour space are mapped to the darkest neutrals of the destination colour space. In most circumstances toggling BPC ON and OFF will result in no obvious change to the image appearance.

Use Dither (8-bit/channel images): as with Black Point Compensation this should be kept "checked". The description box at the bottom of the Colour Settings dialog box will give you some clue as to what it does.

Advanced Controls

As with the Conversion options, this section will only be present in the Colour Settings dialog if the user chooses to activate the Advanced "checkbox". The screenshot below shows this section of the Colour Settings dialog in its default configuration.


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 both settings should be left in the default "Off" condition.

The Desaturate Monitor Color option is the one that has greatest potential to cause confusion as it will result in the image preview to become progressively less saturated as the percentage is increased. Those choosing to work in VERY wide colour spaces may find it useful, however, the majority of  Photoshop users should leave it "Off".

Saving Out Your Own Default Colour 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.

The screen grab below shows my own Colour Settings configuration. Notice that I have chosen Off for my Greyscale Policy and use a customised dot gain for the greyscale working space, you shouldn't try to repeat these settings since they are specific to my Piezography BW workflow.


Customised Colour Settings Configuration

Part 4 - Managing Image/Document Colour Space

On the Colour Space conversion and profile embedding front we find that little has changed from Photoshop 6. Without the tools that follow it would be virtually impossible for the user to maintain a fully colour-managed workflow.

Assign Profile

As with Photoshop 6 the Assign Profile command is accessed via the Image > Mode menu and allows the user to assign any profile of their choosing to an image. The command itself was designed for only a few limited uses, typically with images that have been scanned into Photoshop using a Twain module or a scanner package that has no means of embedding an ICC/ColorSync profile. It will also be useful handling images from digital cameras that have no embedded profile or incorrect EXIF colour space information.

Assuming that the colour management policy is not off, then an image imported into Photoshop with NO embedded profile will be "assigned", "previewed" and subsequently "saved" in the current Photoshop working space. Obviously, this may not be the most appropriate colour space in which to edit or save the image, so assuming the user has the correct source profile we can make the necessary assignment.

It is important to note that unlike the Profile to Profile command of Photoshop 5, assigning a profile will NOT convert the image (will not change the numbers; i.e. RGB pixel values). It simply tells Photoshop the actual colour space that you wish to edit and view the image in (it changes the image appearance or meaning of the numbers).


Other potential uses for Assign Profile include the removal of an embedded profile (i.e. don't colour manage the image). The example screenshot shows a case where I chose to assign a customised profile for my digital camera to an image.

Convert to Profile

The Convert to Profile command found under the Image > Mode menu is basically an enhanced version of the Photoshop 5 Profile-to-Profile. With Profile-to-Profile we were able to define the source colour space (and probably get it wrong), in Photoshop 6 and 7 this cannot be done since the assigned profile for the image is locked. The only way that this source profile can be changed is via the Assign Profile command discussed above.


In the example above I show an image with an embedded profile (Source Space = Canon EOS D30 ..........NSC) being converted to Adobe RGB (1998) (i.e. the Destination Space). Whenever we make this conversion it will be the profile for the destination space that is embedded within the image file when saved. Convert to Profile changes the numbers (i.e. pixel values). The inclusion of 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, use it to your benefit.

Notice that the Intent is set to Relative Colorimetric as this was the default Intent chosen by me when configuring the Colour Settings. However, as with many Photoshop setting the Intent is "sticky", which means that if I had chosen Perceptual instead then the next time I chose Convert to Profile the Intent would be set to Perceptual. The moral being - always check the actual value before clicking OK.

The Profile-to-Profile method of printing an image in Photoshop 5.x, here's its equivalent!

Actually, some users prefer to use the Convert to Profile command to prepare their images for printing, much as they did with Profile-to-Profile in Photoshop 5. The advantage of this approach is that it provides a very accurate preview of how the image will print, and gives the user the ability to use (and preview) the alternative conversion options.


If you do choose this approach for printing then simply select Same as Source (direct equivalent of RGB in Photoshop 5) as the Print Space, the remainder of the settings are as described the dedicated Printer Colour Management tutorial. Of course, the printer driver must be set for No Color Adjustment mode.


Photoshop Print dialog settings required for this method of printing

Also, notice that whereas in the previous examples the Source Space was the same as the Photoshop Working Space it is now the name of the media profile you selected in Convert to Profile (e.g. Epson 1270 Premium Glossy Printer Profile).

Save As

Last but not least, the new Save As dialog throws up a host of useful features. The Embed Profile checkbox is very important and will reflect your choice of Colour Management Policy. You switch it ON or turn it OFF as you please. The latter option being a bad idea in most instances. Notice that the dialog even informs us which profile is being embedded.

The screenshot shown below is how the dialog appears on a Windows 2000 system; the Mac versions will look slightly different, but are functionally identical.


The other save options present in the dialog are those associated with Layers, Alpha Channels, Annotations, etc. Again, we can choose to uncheck them and so save the image without the layers, etc. Note that 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 Photoshop's approach to managing colour. 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 keys words "color management" is all that is required.


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