Im a Cinematographer shooting a short film that place out in the desert. Im using the XL 1 with the Fujinon Lens. the look I have plan out for the end of the film was inspired by impressionist painter Seurat. This means that I want grain in my image without it being dark. I have achieved grain by closing the fstop and having a dark image. How can I achieve grain and still have a bright desert scene.

Try boosting the gain. It will increase the noise, which is similar to grain. Otherwise, the look can be probably be achieved in post.

I would shoot for the cleanest image during prodution and then add the pointilistic (Seurat) effect in post with After Effects or something similar. Increasing the gain will not give you the control over the effect you'll need.

Have you tried a promist one or 1/2 filter, that could do it for you