First of it all you need to linearize your imager and plates.
Expose test strip on the plate.
1, 2, 3, 5, 7, 10, 15, 20, 25, 30, 35, 40, 45, 50, ............, 95, 97, 98, 99, 100% tint.
On non calibrated plate 50 should be 55-57% Adjust expose power to achieve that.
Measure that plate and create...