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QTR-Quadtone RIP

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understanding the QTR linearization function

2014-10-31 by amog19@...

Hi All,

as mentioned, I have started to make experience with QTR and progressing with experiments. I want to better understand how the Curve Creator / Linearization function works. Here is my scenario and question:

After measuring the 21-step grey chart with spyder print I have the 3 column chart (as text file) with LAB L, a, and b values as output. Dropping that file on QTR-Linearize-Data.exe seems to extend those LAB values with a simple graph and at the bottom of the file a line reading: Linearize="value array" - basically listing the LAB L values corresponding with the luminiscence values of the grey patches for easy copy & paste into the QTR Curve Creator / Linearization tab. There is no change to the LAB values. This way I have told QTR what the native L value vor each patch is - not any correction value - right? This means that QTR creates its own correction values based on those L values - right?


Another question: QTR comes not only with a 21-step grey chart but also with a 51-step chart. Does the QTR Curve Creator / Linearization function use these 51 values - thus resulting in a more differenciated linearization? All tutorials I have come across only mention the 21-step chart.


Thanks for your feedback,

Amin

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