I would think that 150 dpi would do the job I just send my work too my wife and see ups the res to 150 I think im sure there are people that know and it depends if it vector it really dont matter if its a photo I would start out with 72 dpi and if there is a mix make the photo make sure its at at least 72dpi do a test of the photo just start go about 18' and see if you like it hope this helps thats why I have a younger wife im old school I do the design then she takes it from there.
OK I TRIED DOING WALL GRAPHICS ASWELL. MY PROBLEM WAS THE COLOR. THE KID I TOOK A PICTURE OF LOOKED PALE IN THE FIRST PRINT. IN THE SECOND PRINT I PLAYED WITH HIM IN PHOTOSHOP AND THE WHITES GOT WASHED OUT. SO FOR ME THE COLOR WAS OFF. I TOOK MY PICTURE IN RAW FORMAT AND JPEG FINE!
There are many other potential issues such as color issues from switching back and forth from rgb to cmyk. Color management is a tricky issue and consistency needs to be maintained as an rgb file until it is processed in versaworks. Photoshop has a tendency to swap color profiles if you are not familiar with all of the settings.
I DO KNOW WHEN IT WAS BROUGHT IT IN TO PHOTOSHOP I LEFT IT AS RGB. BUT I THINK WHEN I ADJUST THE LEVELS I MESSED UP THE WHITES. DO MOST IMAGES NEED TO BE ADJUST IN PHOTOSHOP BEFORE PRINTING, OR WAS THE ORGINAL PALE FROM THE CAMERA SETTINGS?
I agree I always shoot in raw and if possiable use 12-14 mega pixal it great when you see you work come to life we just did 4 52' trailers full wraps we took the pictures so we had complete control and I want to say that 150 dpi worked very well im going to have to look at it was printed at but the photo and how it was taken means so much I never use jpeg aways raw unless my client has the pic then I try to track who took and what format most professionals take it in raw and jpeg
thats whats so good about raw when you start out in raw and your settings are correct you can go back in your photo program and adjust to what you want save it export as a tiff file and you will be amazed at the results. I am by no means an expert on this but I sit for about 2 hours a night trying to figure things so im just learning my self Im way old school I hope im helped just a little.