Mar 162012
 

Granger-Chart

[Update 13 July 2012: Note that I now have a Part 2 on this article at http://www.metalvortex.com/blog/2012/07/12/979.html ]

If you care about accurate colours on the Internet, especially if you have a wide-gamut monitor, then you need a fully colour-managed browser on a colour-managed operating system (OS).

I’ve explained previously why Firefox is the best browser to use, at least on non-OSX platforms such as Windows, when colour fidelity is important to the user.

However, I’ve found a couple of forums where some people are finding that Firefox does not appear to provide correct colour especially when using wide-gamut monitors; this may be a result of having not correctly set up colour management within their OS and/or within Firefox. I think it’s safe to assume that this could be fairly common so I’ve written below a concise set of steps to help. Note that I’m using Windows 7 and Firefox 11 so some of the screenshots may look a bit different depending on your version of OS and Firefox.

Step 1 – Select operating system

If you wish to use colour management within Firefox, the first thing you must do is to ensure that you have an OS that supports colour management (such as Windows 7).

Step 2 – Calibrate and profile your monitor

You must, must, must calibrate and profile your computer’s monitor. This is best achieved by using a hardware-based device such as the Datacolor “Spyder3Elite” or the x-rite “i1Display2”. It’s pretty straightforward these days, however make sure that you create profiles that are compliant to Version 2 of the ICC Specification and not to Version 4 of the ICC Specification due to the rather sparse and sometimes broken support for the latter.

Using non-hardware based software tools is not recommended although, if forced, I can point you to http://www.normankoren.com/makingfineprints1A.html but don’t expect miracles.

If calibration and profiling is not done correctly then you may as well not bother with colour management.

Step 3a – Configure Firefox

To ensure that Firefox’s colour management is correctly configured, we need to makes some changes within Firefox.

I’ve detailed below the steps to take using manual entry but there is an Addon available that provides a GUI front-end to colour management but I’ve not used it.

Anyway, to continue with the steps. Type the following into Firefox’s address bar and hit the Enter key:

about:config

img1

You’ll then be presented with a huge list, at the top of which is a “Search” bar.

img2

Type the following into this Search bar:

gfx

You will now be presented with a list similar to that shown here.

img3

The listing will be different on different versions of Firefox and perhaps also if you’ve done upgrades or fresh installs of Firefox.

Step 3b – gfx.color_management.mode

Mozilla’s documentation for the gfx.color_management.mode values says:

Color management allows images and colors to be displayed consistently across a variety of devices. Mozilla recognizes embedded ICC profiles in image files and uses a local color profile to perform the color adjustments. This preference determines if Mozilla should make these adjustments.

Possible values and their effects

0 – Disable color management

1 – Enable color management for rendered graphics

2 – Enable color management for tagged graphics only. (Default)

In more recent versions of Firefox (e.g. Firefox 11), the property gfx.color_management.mode has a default value of “2”. In much earlier versions of Firefox colour management was disabled by default with gfx.color_management.enabled set to “false”.

I have gfx.color_management.mode = “1” as that aligns with the interpretations of the W3C recommendations that untagged images should assumed to be in the sRGB colour space. I’m not entirely sure why Firefox has the default value set to “2”, but I do think that this is a mistake. So, go ahead and change gfx.color_management.mode to “1”.

A note: I would add that those who have not already calibrated and profiled their monitors are likely to see mismanaged colours with gfx.color_management.mode = 2 or 1. Firefox’s  default value for gfx.color_management.mode should therefore have been set to “0” so as to avoid using profiles that do not match the monitor; the user can then change the value to 1 when the monitor is correctly calibrated and profiled.

Step 3c – gfx.color_management.display_profile

Mozilla’s documentation for the gfx.color_management.display_profile values says:

A string containing the full path to an ICM profile for output. Default is an empty string in which case the systems global profile is used. If no global profile can be found a default sRGB profile is used.

If you’ve followed Step 2 and have just a single monitor then leave the property gfx.color_management.display_profile to a blank value. This will instruct Firefox to use the default monitor colour profile.

Step 3d – for a multi-monitor system

If you do not have a multi-monitor system then you can skip this step.

If you do have a multi-monitor system like mine, then you have to tell Firefox which monitor colour profile to use. The property gfx.color_management.display_profile will need to have its value changed to the path of your monitor profile.

The choice to make here is which colour profile to use; Firefox will only display colours properly when displayed in the monitor of the chosen profile. I’m lucky, in my dual-monitor set-up, that both of my Dell UltraSharp 3008WFP wide-gamut monitors have an almost identical profile so I was quite happy to use either of my two monitor profiles. I chose the one for my primary monitor where Firefox lives most of the time. I do wonder which of the two profiles Firefox would choose if I left gfx.color_management.display_profile to a blank value; perhaps an experiment for the future.

Here’s the path to my main monitor’s colour profile (this is for a Windows 7 machine so your mileage may vary):

C:\Windows\System32\spool\drivers\color\Monitor_Fri 18-02-11_1.icc

Not that the date in the filename is old but only because I’ve re-used the same filename for each of my regular re-calibration and re-profiling exercises so as to avoid changing the value in my other colour-managed software.

Step 4

Just restart Firefox and that should be it; a fully colour managed web browser showing correct colours on your monitor(s).

Good luck!

Article by Kulvinder Singh Matharu – 2012

[Update 13 July 2012: Note that I now have a Part 2 on this article at http://www.metalvortex.com/blog/2012/07/12/979.html ]

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