there are 3 things you need to setup:
keynote > preferences > ruler > ruler units: use inches or centimeters
this allows you to draw, position text and objects accuratly for printing
file > page setup > paper size A4, scale 100%
this allows print settings to match Kenote and choose the correct paper orientation
file > print > print
sends the file to the printer and allows what to print:
slides, notes or handouts
include builds, background, slide numbers
Thanks for the information. I did this, as described, but it is not working unfortunately. Scale of 100 % keeps the printout as small as it is (smaller than the true size of the objects). I don't know why set the scale to 149 % hasn't any effect on object sizes when printing.
I found a workaround meanwhile:
save the drawing as pdf with keynote. Open the file with Adobe, set up page to 149 %. Printout then is exactly the true size of the objects in the keynote drawing.