Warning: sent a 3 foot banner to the printer in RGB and got back a muddy brown mess
Picked up a banner job for a local food truck rally in Boise last month and built the whole thing in RGB because it looked great on my monitor. The orange in the design was supposed to pop, but when I unrolled the print it came out brown and dull, like wet cardboard. I stood in the parking lot of the print shop holding this 3 foot by 6 foot banner just staring at it, knowing the event was in 5 days. Took it back inside and the guy at the counter just nodded and said 'yeah, that happens' like it was normal. I spent the next two nights rebuilding the file in CMYK with a color profile I got from his shop, and the second print came out right. Lost about $60 on the reprint but kept the client. What profile do you all use for outdoor vinyl, because I never want to see that brown orange again.
Ran into the same thing with a farmers market banner last summer. Now I always ask the print shop for their ICC profile before I even start designing, saves you from that awful surprise at pickup. For outdoor vinyl I stick with whatever profile the shop gives me and it's been solid since.