Some time back we added some information to the i1D3 User Guide regarding the accuracy of Correlation Files, and the underlying i1D3 factory calibration.

We tested 3 i1D3 probes at random, and plotted their measurement readings without a Correlation File active.
Unfortunately, some people could not get their head around the concept of what using a Correlation file would/would not do.

So, we have re-performed the same test, this time with 5 different i1D3s, all WITH the same Correlation File active.

The results are the same as the previous tests, but should now be easier for all to understand, with a maximum probe-to-probe deviation of over 2.5 dE00, which is obviously beyond acceptable tolerance levels for accurate calibration.

If you have been to the i1D3 User Guide page before, use Ctrl F5 to refresh your browser, and look for the ? CORRELATION FILE ACCURACY modal button.

I have deliberately randomised the 5 tested probes, but interestingly there is some similarity between some of the tested probes, although as they were all different models, with wildly different manufacturing dates, it is impossible to derive anything from the similarities.

Steve

So a Spectro for probe matching is really the best way? and correlation files wont really give you any benefit due to different hardware responses of each individual device?
Am I reading that right.

The only way to be 'accurate' with any calibration is to use a good colourimeter matched to a good spectro, on the actual displays you are calibrating.
Anything else is a variable, due to the issues outlined.

But, ALL calibration is based on human perception, as that is how the various CIE standards, etc., were defined.
And that itself is compounded with issues such as metameric failure.

There is a point where an acceptance of 'achievable accuracy' has to be adopted.
All you can do is aim for the best possible calibration with the tools you have available.

Steve