I haven't got the greatest images for this exercise but I do understand the concept we are to learn from this. I am tired of getting up at 3:30am to get the dawn shots. (I'll never make a landscape photographer). Pity it isn't winter time when the days are shorter. The first shot is 4:06am the last 21:11. Taken over several days where the weather was similar. ie not totally overcast with grey skies.
The area directly in front of the camera is where the sun sets. So my dawn shots are reflecting the light from the sun. I like this type of light both at sunrise and sunset. As the sun travels through the day the light gets whiter. As I am facing straight into the sun that sets behind the buildings the sunset pictures are not as warm as they can be if the sun is slightly out of the frame. In this group of pictures at this location the images I prefer are those taken between 8:30 am and 11:00 am (2nd row). The sun gives a warm glow to the bricks. This will vary depending on the location and where the sun is in relation to the subject and what the subject is. However the light is richer (and nicer I feel) closer to both sunrise and sunset.
I particularly love the light just before sunrise or just after sunset as in this image of St Paul's Cathedral (taken after sunset).