QTR Calibration with Ink Pattern page --- using it to create a first cut of a curve

[Zero_Equals_Infinity]

I had an idea of how to use the Ink Pattern page, and wanted to know if anyone has used this approach, or whether I am barking up the wrong tree.

So here is the idea:
1) After establishing the exposure for Dmax, print the Ink Pattern page, and scan it in as per a step wedge.
2) Create a spreadsheet, and measure the density of each ink at all or a subset of points, (every 10% sounds good to me).
3) Create a curve "intuitively", and use the show curve function to display it.
4) Add the sum of inks from the spreadsheet at a series of points on the displayed curve.
a) Verify dmin by sum of inks at 100% .... Is the sum >= 100% (and not vastly over 100%). If yes, continue, else adjust curve.
b) Perform sum of inks from the spreadsheet for a series of points on the displayed curve. Adjust ink mix and gamma until a
reasonable fit is found.

Now print a step wedge and scan it to confirm the rough curve derived from the above process. If it is reasonably close, a number of step wedge iterations, equating to time and materials have been saved, and the non-linearization values can now be derived.

Anybody tried this approach? Was it useful or a waste of time?

Thanks,

Nick.

 

[clay]

Yes, it has been something I have been doing for about five years. You will need a transmission densitometer, preferably a UV version if you are calibrating for UV sensitive alt processes. You will also need to have a standard test wedge printed in your chosen print process so you can equate transmission density with print density. Or you can just 'wing it'.