Intro and Question

[Redrobes]

My tip would be to get a sheet of A4 and print a line on it of known number of pixels (preferably an amount to give a long line) and then measure it as accurately as you can. You should do this in both directions. Take the number of pixels, divide by number of inches and thats what your printer is currently doing in DPI which will be slightly different in X & Y no doubt. Then scale your image to the desired number of inches by knowing how many pixels that would be.

[ravells]

My tip would be to get a sheet of A4 and print a line on it of known number of pixels (preferably an amount to give a long line) and then measure it as accurately as you can. You should do this in both directions. Take the number of pixels, divide by number of inches and thats what your printer is currently doing in DPI which will be slightly different in X & Y no doubt. Then scale your image to the desired number of inches by knowing how many pixels that would be.

That is a fantastic piece of advice Redrobes! It neve occured to me that the printer output would have a different DPI to what you set it to on the computer.