Question about Granny Smith Apples?

When a Granny Smith apple tree's fruit is exposed to direct sunlight and intense heat during the growing season something called sunblush occurs. Sunblush is not an industry standard name, but a description adopted by Granny Smith apple packers. It is a visible yellowish to pinkish blush on the fruit surface caused by sun exposure. The flesh is not affected. Sun-blushed fruit are saleable, but represent a potential economic loss since their ultimate grade (and hence their value) may be reduced.