A little bit of serendipity here. I did a precise drawing of a rose window as a component of an ongoing project and added some watercolour to supplement the pen and ink work.
It simply wasn't going to work so I left it and next morning in a half-hearted effort to salvage it I (almost) threw some ultramarine at it then mist sprayed it with water and went to the studio coffee room. 
On return to my workspace the painting had dried out and actually struck me as not too bad and is now something of a work in its own right rather than a component part.
300 gsm smooth cartridge 35 x 50 cms
Serendipity indeed.