While it's true that most large format prints are meant to be viewed from quite a distance, state of the art large format inkjet printers today have enough resolution to print near photo realistic quality. I am working on a logo right now that will be displayed nine feet tall and be viewed from as few as three feet. It has an area with complex bevels that will be nearly the full height of the print. The bevels could be reproduced in Illustrator, but the time required would be huge.
35 years ago we had to create these effects with a REAL airbrush :-)
- Keep your original large image file.
- Decide how much more than 200 px you need and reduce a copy of your file by the the reverse percentage.
- Isolate the areas you want to apply different effects to in separate layers.
- Apply the effects to the desired result.
- Isolate each layer with effects, flatten your artwork and save each layer as a separate file.
- Open each saved, flatten, layer file and enlarge it to the desired size.
- Use blurring and smudging to clean if necessary. You likely won't need much of this except at corners.
- Cut out the effected area from the flatten art (solid color background makes this easy) and paste back into the original (or copy) of your hi-res file. Photoshop does a real good job of enlarging images that have clean lines and smooth gradients.