Here is further evidence that the signatures are forgeries:
Here is an image from when they were being sold on these forums.
Here is an image from Sigourney Weaver's recent private signing:
Here are the key differences between her real signatures and the one on your poster:
- Her real signature has an upward slant to it. Almost every item she signs has an upward slant.
- Her real signature is much more "squished" than the one on your poster. None of her real letter formations are as wide as what's represented on the poster.
- All letter formations are way off. Start by looking at the "S" and the "W" and go from there.
Let's look at James Cameron now:
Here's a true officially signed item-- a Dark Angel card by Topps. These are super limited and show of the nature of his real in person signature:
The only thing remotely unusual about that card is that he usually signs with an upward slant on larger items. The dimensions on the signing space in the card forced him to make the signature a little straighter than usual; but even then you could see it rise from left to right.
Here's a PSA authenticated example that shows the angle I'm talking about:
As you can see, the slant, all letter formations and the overall signature on the poster looks nothing like authentic James Cameron autographs.
Here is another picture featuring signatures on the poster:
Here is what Michelle Rodriguez' signature looks like from a private signing:
There isn't even a signature on the poster that looks like that. I'm guessing maybe they're passing off that mess in the top left as her's.