Color targets for digital imaging

Following on from Tim Vitale's excellent piece on colour targets, I
wanted to add another vote for the 24 patch Macbeth Color Checker.
As he says, it is a good choice for digital photography since the
colours are formed from mixtures of many (more than 15, I think)
inks, rather than through a photographic or lithographic process.
This gives the chart similar spectral properties to a painting.

You might be interested in some free software (for Windows, Mac or
*nix) we have written at the National Gallery which can be used to
calibrate images containing a Macbeth:

    <URL:http://www.vips.ecs.soton.ac.uk/>

There's a page showing how to get calibrated colour here:

    <URL:http://www.vips.ecs.soton.ac.uk/vips-7.8/doc/>

You want the second link down the page.

John Cupitt


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                  Conservation DistList Instance 17:24
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