Aha...... I just did some playing, and here's what I've got. The image I just rendered at 1600x1131 only equals to about 136.797 pixels per inch when I shrink it down to A4 size, which is 210mm by 297mm. So, I'm guessing I'd have to render the image to at least 3200x2262, right? But probably higher... I'm pretty sure I won't be using the Ultra render setting...