Please do not remove the end cap as Darren has suggested..... First of all what Darren is suggesting only works for electric screens. Manual screens have tension placed on the roller so that it will retract. Therefore, please do not remove the end cap. We have placed safety screws on the left end so it is in fact very difficult to remove that end cap.
As far as determining if you got the right screen, do as Tom has suggested and see what happens to the image when you are either above or below your projector and then right next to the lens. Also, take a look at the surface, if it appears to have a somewhat smooth film over the screen it is in all likely hood HP.
Although not impossible, it is very unlikely that we would have sent you a MW instead of a HP. When side by side, the two fabrics are very different.
Blake Brubaker, CTS
Vice President of Sales
Da-Lite Screen Company, Inc.