Problem in taking size of large poster while designing

Dear freinds,

Want to ask something to confirm. That what size should I take while designing a large poster of size 75” into 75” in illustrator?

Also should I design the poster in photoshop as there are images. then what size should I take in it. Please tell complete calculations.

Please reply soon

thanks

In illustrator there is no question you should not have any problem. If its a bitmap picture, ask the producer, what lpi they use. i would doubt they would use 152 lpi.

I already designed a lot of Billboard, much bigger than 75” the document size was 1:10. They enlarged the film.