Finding color in whites, painting in progress

I'm taking a zoom class with painter Erin Raedeke (if you don't know her, take a look at her website.) I've taken several of her painting classes, and I learn more every time. This one is called "Finding Color in Whites". During the week between classes, Erin told us to take a white object that is cool or warm, and arrange it with another white object that is the opposite - warm or cool. I normally don't think about color temperature when I paint - not in words, anyway. I try to match the color I see. It's different for me to label it as "cool" (more towards blue) or "warm" (leaning more towards yellow). So I'm trying to think that way for this class.

Today I spent some time arranging objects for the painting. I was thinking of using a roll of paper towels, lying on a white table with some of the roll hanging over the edge of the table. It was kind of interesting, with very subtle differences between all the whites. I was fiddling with the arrangement when I happened to glance out the window at the house across the street. The people who lived in that house recently moved out. They had always left their garage door open, and there was always a car parked in the driveway. But now the garage door is closed, and the driveway is empty.

I immediately abandoned the still life and decided to paint the house. It was mid-afternoon, and I knew that soon the November sun would be going down. I quickly grabbed a 12" x 9" painting panel and got started. The color of the front of the house, in shadow, looked very blue, so I mixed some Ultramarine blue and Titanium white. I added a touch of Cadmium Orange to desaturate it a bit. The streak of sun hitting the left side of the house was extremely warm, so I mixed a tiny amount of Cadmium Yellow into Titanium White. I had already laid in the darks of the windows, thinly, so I painted the garage door around the darks to form the windows. I painted for less than an hour before the light changed too much, so I stopped. I really hope it's sunny tomorrow, so I can finish this painting. The first thing I'm going to do is correct the color of the driveway in the sun. The color of asphalt has always seemed very tricky. The roof is a similar color. I have to guard against getting lazy and just grabbing whatever paint is already mixed up.