Seeing as you are a fan of botanical illustrations I'd just like to recommend an absolutely stunning colouring book called- The Kew Gardens Flowering Plants Colouring Book (published by Arcturus Publishing) which has quickly become one of my favourites! The book has a total of 44 illustrations, all taken from the archive of the Curtis's Botanical Magazine. The images are double sided. On each page is a full colour image and the opposite is the same but in black and white for you to colour- realistic if you wish:)
Paper good for pens/pencils, I use watercolours although the paper does buckle slightly.
It's currently available on Amazon UK for just £4 as well as some of their other books in the series.
Sorry this post is so long, its sort of turned into a mini review!:)
Hope it will be of interest,
All the best,
Here’s my article about a NZ study published this week that links adult colouring to improved mental health outcomes.http://uk.blastingnews.com/health/2017/11/adult-colouring-beneficial-to-mental-health-002157941.html