I work with people providing oversized graphics for convention displays. The new extended artboard is welcome, and people are using it, and when they export to PDF for print, the giant dimensions gets scaled down to 10% so it's compatible with older PDF versions. And then the printer can just scale 1000% to make the layout its normal size. While this is awkward, it's fine and can work.

But what I discovered today is that scaling down to 10% changes the resolution of placed raster images. So, when that file gets scaled up 1000% any placed images are a lower resolution than the original.

In this screenshot, the left image is an extended artboard layout PDF opened directly in Illustrator, it shows up at it's intended size. The image on the right is the EXACT same file placed/linked/embedded right next to itself. It places at the 10% size and then I scale it 1000% to match the correct size. The problem is that the photo of the wall in the layout is lower resolution in the scaled image. And if I were to zoom in, there isn't any pixelation in the left image, but there is noticeable pixelation in the right image.

This can't happen, it can ***** up a lot of prints where the original file is designed and saved sharp and high-res, but the print is pixelated. Scaling down art is a sad workaround to make things backward compatible, but if it has to be that way, then resolution/dimensions need to be scaled proportionally so that nothing changes when things are scaled back up. In my screenshots, the info window should be exactly the same between both of the layouts since they are the exact same file.

Unless I'm missing something or doing something wrong on my end, but to me, if I place an automatically scaled-down PDF, and scale it back up to its original size, everything should match exactly to the original.