The sun is beginning to shine on the top half of the groom. The darker the bottom half of his suit becomes the more it looks like the sun is shining. With this type of drawing thre is a constant adjusting of values. There is ofcourse a limit to how dark and how light the values can go but until the darkest darks are in then the rest of the values can not be truly judged. All values are relative and the top half of the grooms suit looks lighter not because it has been made lighter but because the bottom half has been made darker. There is still a long way to go and many more adjustments to be made.