The reason could be that the paper has important information that the cartoon character needs. It could be a map, a letter, or some kind of instructions.
Maybe it's got some important information on that paper that it needs to pay attention to.
A sweaty woman cartoon might show her with shiny skin, maybe some damp hair, and maybe she's in the middle of a strenuous activity.
He could be in a high-pressure situation, like giving a speech in front of a large crowd. Or he might have just had a close call and is still recovering from the stress.
The significance of sweaty cartoon characters is that it gives a visual cue of their effort or struggle. It can enhance the drama or action in the story. Sometimes, it's used to show a character's growth or transformation by depicting the physical toll it takes on them.
A sweaty old lady cartoon might show her looking tired or exhausted, with perspiration on her face and maybe disheveled hair.
You can start by adding beads of sweat on the character's forehead and temples. Also, make the skin look a bit shiny to give that sweaty effect.
Maybe it's a cartoon about a hot summer day and the kids are playing outside and sweating. Or it could be during a physical activity at school.
Maybe the kid just had a fight with a friend and their friendship note got torn. That could make them sad.
Well, when cartoon eyes are looking closely on paper, they often have larger and more prominent irises to convey attention. Also, the lashes might be drawn more prominently to add emphasis. Sometimes, there could be little glints or highlights in the eyes to show the light reflection from the paper.
Maybe it's a sports cartoon where the kid is playing vigorously and getting hot and sweaty.