In Chapter 11 Why does Ralph decide that, when they go to meet Jack and his group, he, Piggy, Sam, and Eric should not painted?

Ralph wants to appear civilized. He is serious and wants to be taken seriously..... possibly to remind Jack and the others, who they once were. He is also intent on letting Jack know that he has not embraced the barbarism, that morality and rules continue to be important, but most of all.... he wants to reiterate the idea that he is not like them.

“I’m trying to think. Supposing we go, looking like we used to, washed and hair brushed—after all we aren’t savages really and being rescued isn’t a game—