Digital Projection

I have been asked to scan a quantity of old photographs for a digital slide show, could anyone advise me what resolution i would need to scan them as
iv'e never had anything to do with digital projection before. Thanks.

Most projectors top out at svga or so - i'd go look on the epson web site, see what resolution their best projector has, and use that.

First: Find out exactly which model of projector is going to be used, and find out what resolution it can manage. It's unlikely to be greater than 1024x768 pixels (think: rubbish) and could well be 800x600 (think: extremely rubbish).

Second: Scan at a reasonably high resolution. Photos won't have more than about 300 ppi of resolution in them, so there's not much point in scanning at say 1200 ppi like some scanners can manage. But the reasons for scanning them reasonably large are (a) you're likely to get a better quality result that way; and (b) if there's any further use for the images byond digital projection (e.g. printing) then you don't want to have to do it twice.

Finally, adjust the photos to the exact size/shape needed by the projector. Many projectors aren't very good at handling images that are a different size to what they expect: for example it projects at 800x600 and you give it a 1200x900 image, it might just omit every third pixel. You'll get a better result using proper software to resize them. Incidentally, note that most photos are 3:2 aspect ratio and most projectors are 4:3, so you'll need to decide whether to crop or letterbox.