Illustrator CS3 – upscaling placed or embedded raster graphics with interpolated antialiasing on export?

I’ve designed some popup banners (output dimensions 840mm x 2000mm @ 300dpi) and used vectors throughout with the exception of some stock photography for their backgrounds. I’ve been Linking all rasters as usual, and only when I reviewed my first export at 100% in Acrobat did I notice that Illy doesn’t antialias the raster graphics.

Even at the largest resolution available – £70 worth of stock photography per time – the images still required some upscaling to be incorporated into the banner artwork, so regrettably this was unavoidable.

Annoyingly Illustrator doesn’t seem to either want to / be able to antialias these raster graphics on PDF, EPS or raster export, with upscaled raster graphics simply having their PPI reduced (not ‘upscaled’ in the manner Photoshop would resample) – am I missing some buried config option? The images are so large attempting to use the Rasterization feature that Illy complains about being out of memory (on a fairly meaty 4GB quad core box) and in Acrobat Pro when reviewing the exported PDF, the pixelisation is clearly viewable.

I’m hoping that if I design at quarter resolution the printer will be able to uprez the raster graphic using whatever RIP software they’re using, but I have very little experience in this area; previously all my graphics have been 100% vector in Illy or it’s been practical to use rasters at 100% resolution because I’ve been designing 1:1 with smaller output dimensions. I’ve tried all the workarounds I can think – uprezzing to PSD then linking – failed, 600MB PSD wasn’t liked by Illustrator! – and saving out a 30,000 pixel wide JPEG and trying to Link in Illy – again, import engine failed with memory error. I’ve tried embedding the image, which worked when I disabled the pixel preview, but Illustrator still wouldn’t antialiase the raster graphic.

I have the space of this evening to either figure out how to get round this problem before I have to submit artwork for tomorrow AM, or failing that just bite the bullet and hope the pixelisation isn’t too bad when printed. Am I missing anything blindingly obvious in Illustrator that might be preventing the desired antialiasing on export?

Cheers in advance…

Answer

I’m going to try and answer this question based on the given information regardless of format but under the assumption that these are large-format banners going by the hard dimensions given…

If you are combining large elements like this, I would highly recommend that you move your layout work out of Illustrator and into InDesign or Quark, then output to PDF from there. Illustrator is a vector-drawing tool first, and has only minimal image-handling capabilities. A proper page layout application is better equipped for this type of work. I’ve seen Illustrator “choke” on large art as well, and by your account, you’ve gone beyond what I can make it choke on.

You should also speak with your printer about how well their RIPs are going to handle what you’re sending and for best specs in dealing with raster art. Your printer is there to help you get your job out as quickly as possible. I would never send a 600 MB PSD file to a printer; it would be flattened first, resized to the proper resolution, and then placed in the layout. My experience is also that 300 dpi is more than sufficient for most images being used in banners provided it hasn’t been scaled up too much. Most large-format RIPs do a handy job making the art look good from a distance.

Finally, you need to be working with TIF and EPS files, never JPGs. JPGs aren’t designed for this type of work.

Attribution
Source : Link , Question Author : Chris Woods , Answer Author : Philip Regan

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