Because of the intensity of the colors in the tulips, I set them against black to take advantage of their vibrancy. They were still tightly closed until I turned on the spotlight. They unfurled as I painted.
As I drew with thinned cadmium red - it doesn't contaminate later colors and leaves a sparkle if I miss a spot when painting over it - I considered the directions of the leaf lines as well as the overall placement on the canvas. The vase and flowers were so dominant, I decided that they should be closest to the viewer. Normally, I have still life objects in front of the vase in a floral that serve to lead the eye into the arrangement. There was no question of where to go with these!
Because I knew that the flowers would change quickly, I established their colors immediately, comparing yellow to yellow, red to red, and white to white. This was a break from my regular method and I knew that I would make considerable adjustments after the surrounding colors were in. Placing a new color next to an existing one ALWAYS changes the existing one.
Here, I've added that dark background. It really intensified the tulip colors, didn't it? I made careful note of the color differences as the light traveled across the tablecloth and passed through the water-filled vase.
I toned down the yellow pot that was behind everything and changed it to look like more of a tray standing against the background drape. I used its curve to repeat those of the leaves. As a pot, not enough of it showed to explain what it was, but I needed something to bring some action to the lower part of the painting. I couldn't eliminate it entirely.
I compared the color on the lighted side of the pink vase to the pinks in the flowers and hit a warmer, somewhat grayed pink. Putting a cool, grayed pink on the shadow side made the lighted side look warmer, too. Notice the warm versus cool on the teapot, as well.
At the end of this session, I turned off the lights and heat in the studio, so the flowers would not open too much to work the next day.
Best laid plans didn't work, though. The blooms were tightly closed again when I opened the studio the next afternoon and turned on the spotlight, but the hour I let the studio warm up was a bit too much. When I returned, the tulips were much more opened and had moved a lot as they chased the light.
Instead of redrawing all, I simply added some of flowers in their new location and state. This filled out the bouquet and added more interesting shapes. The white bloom with red stripes inside is actually the one on its left as it opened and moved. It became the point with the greatest value change and hardest edge.
Note also, how I softened the edges of all but a few of the tulips.
Because of the action in the bouquet, I included all the variations in color and value present in the vase, table drape and other objects. Both light highlights and dark accents contributed.