The variation of sky color from dark at the top to light at the bottom becomes even more apparent in this view, because here again, I've omitted this darker color from the tiny points of sky we see peeking through in the lower right of the drawing.
The photo I took of this step, for inclusion here, does not accurately reproduce the actual colors existing on the drawing, at least in the background, which actually is still a pure white. That is true of some of the other shots I've taken, as well. There seems to be a dark pink shadow on the lower part of the sheet. I made the mistake of taking my photographs with the drawing propped up above a red floor, and apparently the reflection is showing up in the photos. Just pretend I did it in order to demonstrate a good example of what NOT to do when taking photos. I'll try to correct that in the future.
However, you can see from the photo that the blue is much darker now and the lower right is much lighter than the rest of the sky. I used a medium pressure through most of the Denim Blue layer, but beginning in the middle of the sky, I wanted the blue to gradually start appearing lighter as it proceeded down the trees, so I used progressively less pressure, the lower I got.
At this point the blue looks dark enough, and I'm pleased with the overall color of the sky; but keep in mind that at the present time, I'm viewing the sky with a bright white background adjacent to it. Later when the leaves are colored in, the sky color might need to be adjusted. Sometimes your eyes can play tricks on you.