what size are they?
One possibility is that better equipment can 'see' defects in the originals a lot better. Better equipment is also better able to reproduce the defects.
If they are color photos, and you want to keep the color, one thing you can use is a noise filter like Noise Ninja. It will cut the noise, but will also blur the details slightly. I use a denoised layer on top of the original image layer. I then restrict the denoising, via a mask, to areas where the loss of detail is not an issue. Smooth skin and shadow areas are prime candidates for inclusion.
I just purchased a HP2710 Photo Smart multifunction printer and am having some issues....I'm hoping with a few tips I can get this to work. I really wanted to purchase a cannon photo printer because from what I read they tend to produce better quality photos, but my company was willing to fork over $200 bucks towards a multifunction printer for my home office, provided it had fax capabilities and the 2710 fit the bill and it only ended up costing me 50 bucks so I can't complain, plus I'm only repriducing potos for home use so a slight difference in print quality doesn't make all that much of a difference. I've blown up some of my wedding photos to 8 x 10 in the past with really old equiptment (cannoscan scanner and an HP 810 deskjet printer....really really old) and they came out decent, but now 5 years later they are starting to degrade rapidly (skin tones are getting really pink). I know its due to the types of inks the old hp used regardless of the high quality paper I printed them on. Now that I have this new "somewhat" high end photoprinter I figured I'd replace all my 8x10 around the house. The problem I'm having is that when I scan the originals I'm getting alot of "snow/noise" in the picture. It is especially noticable in the dark areas....i.e. shadows, black tuxedeos, dark hair....etc. I'm pretty sure it's not an actual printer issue because I can easily see the snow/noise on my monitor (not just on the printed photos), so I'm assuming its a scanner issue. I did print a few 4x6 samples using the HP photo cartridge (instead of straight black) and high end paper just to try and not ruin any of my 8x10 paper first. As I thought, the snow/noise transferred to the printed image. I've tried scanning at multiple resolutions 300, 600, 1200 & 2400 and the on screen image still shows all of the snow/noise. I can only imagine if I increase picture size to 8x10 the problem will only be magnified. I've also played around with the image with the HP provided Image Zone software and any improvments I made only improved the image marginally.
Any help would certainly be appreciated.