The Winsor & Newton Hardback Sketchbook comes in A4 and A5 sizes with 96 perforated acid-free white pages. There are also spiral bound ones. The cover has a faux leather effect.
The paper is 170gsm, quite thick. It's slightly smoother than normal cartridge paper. On the surface, sometimes you can notice tiny grey specks that are not white, probably due to the paper pulp not being pure. Unless you need it to be pure white, it's probably a non-issue.
That's how the perforated pages look like. Towards the middle of the sketchbook, the pages will actually fold two times, one at the perforated edge, and one to the side away from the spine. You've to tear the perforated pages carefully or you can actually tear the page off from the spine instead.
The sketchbook pages don't open flat. I've a scanner that scans well only when the paper is in contact with the glass, so this sketchbook isn't easy to scan for me.
This sketch is from a Lamy fountain pen and watercolour.
The paper absorbs watercolour well and doesn't bleed to the page behind. It can take around 2-3 washes when the previous wash is dry.
The paper works quite well with ink but can be quite absorbent depending on the pen. I've used a Pilot Techpoint above and if you hold the pen tip against the paper surface for a prolong period, the ink will start to spread. Cartridge paper won't do this. Pen and ink users should note that.
Overall, it's a fine sketchbook. My only issue is with the perforated pages and how they are spread apart in a way that makes scanning tricky.
Search Jackson's Art Supplies (UK) too.