I found a quick solution to determine printing parameters instead of using the popims A6 calibration Image downloadable at http://www.popims.com/en/animator.htm.
I printed with popims a calibration image of myself: made with an image editor (1787 x 1181 pixels) . On a white background, I draw several squares and rectangles with a size varying by step of 300 pixels ( normally made 1 inch at 300 dpi).
After printing this image, I measured the largest rectangle (1500 pixels width) and found 5,21875 inches instead of 5 inches. So a simple computation give me the correct printing parameter: 0,9580.
Ps: Sorry for my awful English!