Hi Peter,
I read the same tip as Readydale somehere too (only the tip was to make 4 scans not 2 so the light hits the texture from all 4 directions). Here's a link to a 'how to' video for 2 scans:
https://www.youtube.com/watch?v=Vy7NALaYmQ4.
On removing the (remaining) texture, the blur tool doesn't work very well for me on rougher textures. It's fine for smoothing out very fine texture but on this kind of rougher texture, it just seems to create 'lumpy' (or scaly) surfaces.
So my approach is usually to separate the details (lines) from the colours/tones on two different layers:
1. Make two layer copies.
2. Blur the first layer copy just as much as needed to smooth out the surface and remove the texture using a filter like 'Dust and Scratches', a Median filter or a Gaussian blur. See which one works best. All the lines and details will be blurred too.
3. On the second layer, apply a high pass filter to show the lines (and unwanted texture details). Add a third (masked) layer and colour it grey. You might even want a fourth (masked) layer for white. Tie these two layers to the high pass filter so they only apply to that one. Using the masks on the grey/white layers, paint over the unwanted (texture) details on the high pass filter layer. You can vary the brush and layer transparencies to let a bit of texture though so that the surfaces you paint over aren't a completely 'flat' colour. The result of the second layer (with the 'paint' layers applied) is a high pass filter that just shows the details and textures you want to keep. The 'noise' and unwanted texture has been painted out. The blending mode which seems to work best is 'overlay'. Duplicating the the high pass layer or adding more contrast to it with a tied curves adjustment can sharpen up the details even more.
So now you have blurred surfaces on the 1st layer with the paper texture removed and a 'details' layer with just the details you want to keep, It takes a bit of playing around with to get get the transparencies and blending modes just right but by using masks for both the blur and the details, everything is non-destructive and can be readily adjusted to get the final result you want.
This approach is similar to the 'frequency separation' technique used in retouching:
https://fstoppers.com/post-production/ultimate-guide-frequency-separation-technique-8699Making 2-4 scans and combining them, will avoid most of this 'correction work' altogether. But it's an approach that I've found useful when re-scanning is not an option.
I sometimes use this painting 'colour/tone (masked) layers' technique without filters just to even out the colour/tone in damaged areas of a photo. So for B&W photos the layers (matched to the photo) would be black, white, dark grey and light grey. It's sometimes quicker just to paint over large damaged black, grey or white areas than to remove individual spots, stains, tears and creases with patching, cloning and spot healing. Depends on the photo.
Hope this helps,
Mike
PS. A rough and ready example is attached. Not all that accurate. Some manual 'blur' is still needed around the eyes and mouths.