Friday, 19 March 2010

the problem with colour: making machines see the same

The problem with colour is that no-one really knows what we're looking at. A recent discussion reminded me that no matter how much is written on this topic that perhaps there is still room for writing more.

Of course people who are starting down this path will have purchased a tool such as a Spyder to "calibrate" their monitor. This however is only about 1/3 of the chain of events which are important for getting everything right from your desktop to mine.

Browsers are mainly unaware of colour profiles, so the "default" is sRGB. Its not well understood but Macintosh are much more advanced in this area and Safari is cognizant of colour profiles. Which can lead Macintosh users to make stuff which looks fine to them but sucks for their clients and audience.

Getting back to the discussion about an image, the image in question was this one.

Which with everything in the colour chain working properly looks quite nice ...

sadly in my Firefox browser it looked ghastly on the Flickr page ... looking at this segment in particular, it looks like the colour channels are blown.

However all is not what it seems, because when downloading the image from Flickr I found that when opening it in my default viewer (Irfanview which is not colour profile aware) it looked great.

So I then opened the same flickr page to see the image in IE 6 and it looked fine there.

The picture is beginning to form, and its all down to small errors in the colour management chain.

To muddy the waters a little more Firefox 3 has just introduced colour management (2.0 does not have it) and it seems to not be at the right standard just yet (read this for instance).

So, when I open the image in Photoshop I got the following message:

which indicates that the image had the Adobe RGB profile associated, but seeing it in Photoshop with the right profile associated with it again looks dreadful

so, now, to simulate the effects of a non-colour aware application, I assign the sRGB profile and then preview it using the "monitor" as the preview tool .. and suddenly it looks OK.

So, to photographers out there who are playing with their images in Photoshop just be careful what you do with colour profiles. You may see things the right way (cos Mac is simply more consistently better in this area and only a few applications on PC cope with colour manaement, and nearly none Linux) , but your audience may not.

Do your audience count to you?

That's your call, but the rest of the browsers in possession of 98% of the viewing public will not know this. and see your images badly.

I recommend that you keep your camera set to sRGB as the colour space (not Adobe RGB) and be careful when working with raw exactly which profile you import and convert your RAW images into (RAW has no colour space). If you intend to display them, you need to convert the image to a profile of sRGB.

Cambridge in Colour has an excellent tutorial on this, which I recommend. But keep in mind essentially this: If you're editing in your preferred working space, remember to
  • save As for your reduced web sized image
  • convert (not assign) the profile to sRGB
  • make sure your rendering intent is set to perceptual
and you should be fine :-)

Lastly, I'll suggest that those with patience read this fellows page. He knows his stuff well, even if his HTML looks like a blast from 1991 and he is a self declared Mac addict.

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