Check linearization of measurements // linear regression

1

Dear,

What’s the best approach to check the linearization?

After a linearization with PPE and using the new curve - measuring the L*.
Measurements of the L* to make a linear regression as following:

I’ve found two methods:
–> Linear A (using Excel-equation FORECAST): the calculated values at point 1 and 31 are not the same as the measured L*-values.
–> Linear B (manual); the calculated values at point 1 and 31 are exactly the same as those the measured L*-values.

regression

==> What’s the method to be used for furhter evaluation?

And to evaluate if certain shades are too light or too dark compared to the "ideal’-vaules (linear regresseion). If the measured L*-vaues are above the linear regression, the print is too dark. If below, too light for the concerned shades.

Thanks.

Peter

2

Dear Peter. There is only a 51 and 129 hard-coded gg2.2 target for the ColorMunki so what target are you using for the 31step? Is it of your own making? Does it have untagged color-space without encoding gray gamma 2.2?

best regards,
Walker

3

Sorry Walker - still learning …

I’ve used the ColorPort Piezography-31x9step-i1Pro.tif Target
Normally for i1Pro - I’ve understood that the ColorMunki have the same ‘hardware’.
And to reduce the measuring error by measuring 9 x 31 Patches I’ve used this Target.
–> It this an acceptable approach?

And to check the linearization I assume to use Linear B as above?

Regards, Peter