On the left side of this image comparison you see a scan (source: commons.wikimedia.org) of Henry Holiday’s illustration to the final chapter The Vanishing in Lewis Carroll’s The Hunting of the Snark. It already is a quite faithful reproduction of the original illustration.
In prints made by Ian Mortimer (for a limited edition of The Hunting of the Snark published by Macmillan in 1993) from John Swain’s original woodblocks, the illustration has better quality, but looks even darker. That is as faithful to the original as it can get.
I think that in the original printing, the dark areas of the illustration grew wider than it was intended by Henry Holiday. It looks as if too much black ink spilled into the white areas. Therefore I scanned the illustration from my own 1st edition of The Hunting of the Snark. Then I grew the white areas a bit. (First I enlarged the image by 2:1. Then I applied GIMP → Filters → Generic → Delate. After that I scaled the image back to its previous size.) You see the result on the right side.