Test Cards for Monitor Adjustment – Revised

Test Cards - 1Test Cards - 2Calibration and Profiling

I have updated the page on this subject in order to clarify the distinction between calibration and profiling (or characterisation), and to remove reference to commercial operating systems now obsolete.

To avoid confusion I have now included only a version of each test card with sRGB profiles assigned and saved as jpegs. These should be viewed in an application that is colour aware (i.e. one that recognises and uses the embedded profile).

Click here for Test Cards page

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Test Cards for Monitor Adjustment – An Update

Test Cards - 1Test Cards - 2Basic adjustment of monitors and projection systems

When I last updated my page on this subject (2012) I decided that it was best to offer the test cards as .png files and leave it to the user to assign a profile (presumably sRGB) and to view the result in an application such as Photoshop. For convenience, I have now added a version of each test card with sRGB profiles assigned and saved as jpegs. These should be viewed in an application that is colour aware (i.e. one that recognises and uses the embedded profile).

Click here for Test Cards page

Measuring Monitor Gamma

I have devised a method of measuring gamma without the need for special equipment – a way of setting up a display which is independent of the operating system. Commercial profiling systems don’t seem to provide software for Ubuntu (Linux).

There are several charts and applets on the web which rely on subjectively matching stripes and grey patches but whilst my method uses the same principle the match is based on measured luminance rather than on human judgement.

Gamma measurement

The method uses test targets displayed in Photoshop (or other image/graphics processing application) – which has the advantage of predictable colour management – and hardware costing about £10 (US $16) including the meter!

I have just added a page describing the system. Have a look and feel free to comment.

Test Cards for Monitor checks (2)

Since my previous post and uploading the page on this subject I have noticed that the test cards look different in different browsers. In IE and Chrome the shadow card shows a just perceptible difference between the ‘4’ patch and the ‘0’ background. In Firefox, Seamonkey and Safari there is a more noticeable difference. I believe this is because these last three are implementing colour management and are showing the card ‘correctly’. This was confirmed by viewing the file in Photoshop and selecting either ‘don’t color manage’ or using the embedded profile (sRGB).

I should point out that since the page was originally uploaded I have replaced the jpeg test cards with .png files so as not to confuse matters with embedded profiles. This does not in any way invalidate the above statements but it does mean that to view the files correctly in Photoshop a profile (sRGB) should be assigned and colour management applied on opening. The appearance of the test cards (now without embedded profiles) in the listed browsers is unchanged, suggesting that those browsers implementing colour management are assuming an sRGB profile.