Hello, I hope this is the right section to ask for some help. I am working on a file in Adobe illustrator and I want to make a large BW negative 60" long 25" high. That's just a rough size. I'm not too knowledgable about negatives. For the B&W negative everything in the artwork like the white background with black artwork would be inverted in the negative.

Just so I'm clear the negative would be black and anything with black artwork would be transparent. I live in NY and if someone can please help, I'm looking for company that can help me with that or anyone know please let me know. Thanks