I don't think these expressions should be translated. It may confuse you even more. I'll try to explain them. 1) "I don't talk him about politics because it is like a red rag to a bull." If you wave a red rag (or a flag, or a cape) in front of a bull, it may attack. Think of that image if you talk to the other parson about politics. "Like a red rag to a bull" describes that kind of reaction. 2) "He takes the optimistic view (perspective) and talks about a _______ skies scenario." What colour is the sky when the weather is nice and pleasant? ;) 3) "Now that they have read it in black and white, they believe me." If something (a picture or text) is in black and white, it is clear and perfectly understandable. So this means you have given them very clear information.

En sentido figurado: " No hablo de política porque es conflictivo, es como torear a un toro o poner una capa roja a un toro. Coge o toma la parte positiva de las cosas y habla de cielos azules o de aspectos positivos de la vida,pues si hablas en blanco o negro no te van a creer , o si hablas en blanco ynegro es muy pesimista-

No le hablo de la política, porque es como una capa roja a un toro; Toma la visión optimista y habla sobre un panorama cielos azules; Ya que lo han leído en negro y blanco que me creen.