If it helps, a native "English" speaker & love of grammer, with regard to the understanding of the use of I'd:
I' d = I would vs I had
It is all in the context;
"I'd read the newspaper" = I had read the newspaper
(meaning, you have read the newspaper. As if you were acknowledging a story/article you both had read, about independently in that day's newspaper)
"I'd read the newspaper" = I would have read the newspaper. Implying, you would have read the newspaper if you got/received the it. - Note: this is improper grammar use, as it would be proper to say, "I would've read the newspaper...")
The ambiguity is "read". Present or Past?
R-E-a-d (present) or R-E-d (past) <- pronunciation emphasis, not spelling