Trying new things - gesso board

I've read something on this surface for a illustration purposes and I saw a video of Jeff Watts doing some gorgeous stuff on a similar type of illustration board on youtube also so I've had a desire of trying it for a while. So finally - last week I took an advantage of a black friday offer at Jackson's art supplies (https://www.jacksonsart.com) and ordered some of these goodies. I also gave a try to Jackson's series of brushes "Akoya" and "Shinku" and both of them are great (especially brights from Akoya have a great control).

I've decided to try a gouache because I had the drawer with the paints still opened :-) you know - from my previous post.

I must say it is a very fine surface and took a while to get used to it. On watercolour paper you don't actually have to use to much pigment because it's more absorbable - but you can lose saturation of colours. With gesso board you're more forced to use more pigment (more paint) and thus you're even more on the side of the oil painting (meaning behaviour of the colour) and you don't lose the saturation. The result is more matt of course (than oils) dependently which brand of gouache paint you use. Because the surface is so fine it's a great stuff for detailed work so now I get why they call it illustration board in the first place.

Can you guess what's the measurement of the board which I used for my first attempt with this material accordingly to the detail of the finished painting?  (see the answer below the picture)

"Tiger study" (Gouache on gesso board 10x15 cm)

Yes it's a very small board yet still you're able to put a lots of details because it's so fine kind of surface. 

I must say I felt in love in this material and in the future I will use it especially for more portraits. 

Thank you for your time. See you shortly. Petr