Sea & Sky Andamento Study

I was a bit stuck on how to do the sky of the Sea & Sky mosaic. After staring at it for a while and roaming off to do other things only to return to staring at it I decided to do an andamento study and see if I could get unstuck.

The sticking point was that if I want to finish the mosaic using the same type of glass I'm limited to two colors (or make a trip to Kokomo Indiana for more colors...). There's no blending - or at least no painterly blending - possible in mosaics. So only having two colors for the sky was making my head spin when I thought about how to proceed. My options were:

1. Do the sky in a different type of glass. Even if I thought this would look good (or if I could come up with a way to make it look good) I still didn't have the colors that I thought would look right.
2. Do the entire sky in one color - except that I didn't have a sufficient amount the color I would have used (if I did do it that way). Glass quantity aside, I think that would have made the sky exceptionally flat (color-wise, not texture-wise)... not a good thing, in my opinion.
3. Find a way to do the sky with only two colors that would make me happy. 

So after fretting over it all day yesterday I decided last night that the first thing I would do today was the andamento & color study. I needed to come up with an idea that would result in a pleasing junction between the two colors that wouldn't be harsh or jarring or fix the viewer's eye.

 In addition, the andamento needed to suggest wind currents that were moving/flowing in an interesting, believable way. The wind currents needed to be present but less dynamic than the water currents.

Step 1: Draw the what-I-have-done-so-far on a page in my large sketchbook. This drawing is full-scale. I did not draw the water, just the horizon line/boundary of the sky and the sailboat. Sometimes I only have a blank square or rectangle at this point.

Step 2: Attach a piece of tracing paper above the drawing. I use tracing paper so that I can do as many sketches as I need to to get it "right." I can explore different andamento and see how changing the flow of the glass (or stone) alters the work. For this piece the andamento was only going to be flowing in one general direction, but on other pieces I might sketch in a focal arrangement of glass or stone and then play around with the andamento around it.

Step 3: Explore the color shift. The entire point of the andamento study was actually to do a color study so once I was happy with the andamento I attached another piece of tracing paper and tried to figure out how to make the two colors work.

I haven't decided if this is the right way yet. I think it is the right way based on the andamento. But I might want to try a different andamento and color path.

I'll have to let this set for a few hours or a day or two and see what I think about it.