Hi Anna,

Keith is right...when they speak of 300 ppi, that means 300 pixels per inch. To calculate your render size, multiply the inches of the width and the inches of the height of your print size by 300.

For example, an A1 is 594mm x 841mm (23.4 x 33.1 inches) - so:

23.4 x 300 = 7020
33.1 x 300 = 9930

So to render an A1 at 300ppi, you would need to render the image at 7020 x 9930.

The following is a link showing international paper sizes in mm and inches:

http://www.hintsandthings.co.uk/office/paper.htm