I am making a banner for my company at about 8 x 4.5 feet. I'm wondering what I should scale the format down to and what resolution it would require for the company to be able to scale it and print it that big?
Where will the banner go? how far away would a regular person stand whilst viewing it?
For example billboards are often designed at 12-30 dpi because it has very large proportions, a much lower DPI is fine because this type of image is viewed from distance and not up close like a magazine or photo etc.
For the size of banner you are designing, it should be approximately 150 dpi but if in doubt - always ask the printers.