Hi Tinkey Winkey. 48bit scans will give you finer gradation of colour shades. The dpi rating defines how much fine detail the scanner can resolve. What you also need to take into consideration is what the OPTICAL resolution is. The published resolution is often obtained by interpolation, i.e. the scanner electronically calculates the points between those it actually samples. The A$ scans should be no problem. When finer resolution helps is when you scan a small image and then stretch it, very much like using electronic zoom in a digital camera. For 1:1 scanning you are unlikely to want to scan at anything greater than 300, or possibly 600 dpi. Greater than that is likely to result in a HUGE file size. Most printers will only give you 300dpi anyway.