Compensating scanner distortion - looking for volunteers with a scanner

[Krikor]

1. Get the ofn-scanner-fix package - ✔
   
2. Install and read the doc carefully - ✔
   
3. Do the "acid test" on your scanner. How bad is it? - ✔ (see image last post)
   
4. Use the doc and the script to generate a compensation map - ✔
   
5. What is the scanner error (first number in the parentheses)? What is the scanner make/model? - ✔ ((7,   0.487,  0.553) - EPSON ESC/P-R V4 Class Driver)
   
6. Use the map to fix things - (IDK)
   
7. Did it work? How well/badly? - (IDK)
   
8. Any problems in particular? - Yes. I confess that I didn't understand the instructions well and I had difficulties in achieving this result.