should i seal my watercolors paintings with something when i am finished with them? i am teaching my self how to paint with them & i did not know if you were suppose to or not. also what would be the best paper to use, i did some on watercolor paper i got at walmart as that was the closet place to find any in my area & i noticed my paintings look grainy, i had some made by Stratmore& my paintings seem to come out alot smoother looking but i only had a few sheets left over from my aerosol art. i will have to order some paper on line as there is not a decent craft supply with in 100 miles of me, so i would appreciate your input as to what i should be looking to order.i have 2 of my watercolors posted in my gallery & you can see what i am talking about,one on walmart Poo, & one on stramore. thanks for your help. ZAZ