Is it a good way to work if I use standard paper instead of negative media (I won't reverse the greyscale).
And if so, my paper has some sort of pattern (Epson Cold Press); do I have to blur it in Photoshop before reading it?
The QTR Build Curve script can also be used to build a correction curve for a positive print. For a standard positive print just print the 21 step wedge and scan the print and derive the .acv curve. In this application you would not invert the step wedge file.
Slight blurring might help with some papers, or with digital negatives to smooth out process artifacts.
Sandy