Raw scanned image, not a terrific scan, saved with JPG so there's artifacts, and it's not a very big image either, its shown here full size:

JPG artifacts removed with a filter:

So we apply a jpg artifact remover, double the image, apply a median filter, double the image, apply an edge preserving smooth, double the image, apply an edge preserving smooth:

While there's a noticeable difference at this resolution images that need to scale up look better when using this technique. Consider the following scaled up images: