There are several synonyms for the phrase "makes lighter". These include "brightens", which refers to making something physically or metaphorically brighter or less dull. "Eases" can also be used as a synonym, and is commonly used in relation to relieving stress or pain. "Lifts" is another option, which can refer to physical lifting or metaphorically lifting one's spirits or mood. "Allays" is also a synonym, meaning to reduce or alleviate anxiety or fear. Finally, "lessens" can be used to refer to reducing the weight or severity of something. These synonyms can be used interchangeably depending on the context and intended meaning.