You compare white to other colors, and find out it's different from all of them.
Breakdown of all
You bend towards the sun, and are covered in white light.
You compare two spoons, and find out the left one is less curvy than the right one.
Usages of all
A wall surrounds all stories of a building. That's why the roof isn't considered a story.
Often written using hiragana instead of kanji.
Can also refer to things instead of people, but 全部 is more common in that case.