Well, in this process of creating a scene of dense and dark clouds we have learned to use darkness to emphasize that characteristic of clouds loaded with water...
The colors have been previously prepared for use before the paper lost the shine necessary for the stains to spread creating the clusters...
The most complicated thing about this watercolor was that certain parts remained clear or in some cases, that the white of the paper prevailed...

I have used two papers to test the change and the clear difference between a 100% cotton cold-pressed paper (coarse grain) and a cold-pressed paper mixed with cellulose and cotton... Both 300 grams.

It's possibly not the best sky watercolor I've ever done, but here it is.

 

My results 

1. Cellulose + Cotton paper (FUUMUUI BRAND) 

 

 

2. 100% Cotton paper (Final and definite result)  (BAOHONG BRAND)