Suggestions for ameliorating scanner rape:
1) Scan to produce the highest resolution PNG possible. PNGs use a lossless compression process, unlike JPGs. JPGs and JPEGs smear out a lot of high frequency data, such as paper texture.
2) Put the PNG into Photoshop and apply a Levels or Curves adjustment layer to bring out the texture and other high spatial frequency detail.
3) Reduce Image Size to no more than 1280 pixels in either direction.
4) Save as a high quality JPG or JPEG.

If you don't have Photoshop, email me a PNG that is under 10 MB file size, and I'll be happy to give it a try. You can see some of what I've done to reconstruct vastly worse scans in my Scraps.

Thanks for your input, foxy, but I'm already well aware of what the correct process should be. Applied it here, too. Even so, it's tricky to get the right combination of (both pre and post scan) level settings that actually reasonably match what's on paper. Let alone doing it so that the paper itself comes out pure white, yet not having it so overexposed as to wash out the colours, too.

And then my scanner seems to do this "halo" thing with bright colours, like the pink. (Maybe the glass just needs a clean. Actually, the more I think about it... )