white as a sheet—very pale, usually because of illness, shock or fear:
- He must have done a pretty good imitation of a gangster because the guy’s face turned white as a sheet.
white as snow—is said of very pure white color:
- Anne walked with him to the house up the brook, over a field that was as white as snow with daisies.
Note: Neither expression correlates in meaning with the phrase whiter than white—said of a good and righteous man:
- Having come to power promising to be “whiter than white,” Blair’s government may find it difficult to redeem its once spotless reputation.