Comparing OT with PT you can clearly see that the sun is almost visible in the various space shots when in OT is not.

but when the MF arrives to the DS we see a lens flare behind it.

Like ady added yavin it could be interesting adding sun in several shots that light appears coming from nowhere.

Same goes to PT too removing the sun to match with the retro fact and so on.

@Mr J: I was wondering if you can play with vader movements in ANH.

A few examples are when he interrogates The rebel dude in tantive he turns his head way to fast for ESB vader standards. As well in the next shots that he is yelling he is moving too fast. Considering the fact making him less like a coffee freak and more as a lord we know in ESB many of his moving can be slowed down. No idea if this can work.

-Angel and Blue