Yupo, by the way for those of you, who don't know is a synthetic watercolor paper. Painting on it is unusual because the paints do not respond to this synthetic watercolor paper as they do on traditional absorbant cold or hot pressed paper . The paints dry more slowly on it, the paper doesn't change, and the paints may be removed if you accidentally or deliberately add water to it.
To ensure durability you have to spray your finished product with archival varnish. Why use it? See this is the essential difference between both mediums. Yupo is erasable. So you want to secure you work. Thus the archival varnish which not only makes it Ultra Violet Light (UVL) resistant but also protects it against moisture, etc.
One other difference is that Yupo paper keeps the colors brilliant and strong in hue. That difference makes is very attractive but also requires getting used to. So here is my latest attempt using this paper. If you really like it, please go visit my shop on www.etsy.com