I was working on a 5x7 watercolor last weekend that involved a lot of glazing. The subject, a cat with gorgeous green eyes that I really wanted to expand on and create a level of depth and mystery that wasn't apparent in the reference photo.
I went a little outside my comfort zone on this one and selected hot-press paper (smooth, not rough) so that I could achieve a more glassy appearance to the eyes. I find it more difficult to blend the cat's fur on smooth paper, but seeing as how the eyes were the focal point, I suffered through the limitations while working on the fur.
I chose a mixture of cool and warm yellows and greens, ending with a punch of Phthalo Blue
I began by wetting the entire eye area with clear water, then dropped in a bit of Helio Lemon Yellow (cool). I let that swirl around a bit before adding a little Viridian. This I pulled out towards the edges a bit, then used my brush to gently guide it to the edges. I also had to tilt my paper in several directions to get the flow just right.
I let that dry then came back with a bit of Gamboge (warm) and Olive Green (warm) employing the same techniques, but with less water. With every subsequent glaze you want to use less water - this is one difference between a glaze and a wash - washes have more water added to the paint. After that dried, I added a bit more Viridian and a little Phthalo Blue right where the Iris would be - so that it would add more depth. I "pricked" the paint with very small dots of pure Phthalo so that it would bleed in a little bit more. I added Pure Black for the Iris. Usually I would mix up a deep black using green and crimson, however I wasn't using any crimson here so it was easier to grab a little black from my dry Stabilo Watercolor Crayon - a touch of water to the end of the crayon and I've got a nice easy black with no mess.
The shadows were added after the rest of the painting was finished, and I opted for White Gouache highlights at the very end. I had not saved any white paper for the highlights because I wasn't sure if I wanted any when I began the painting.
Have fun experimenting!