Another interesting InDesign 2.0 discovery this week. I’ll write up a document about this once I get my head around the implications – and can create some relevant screen dumps.
Many RIPs (and not just older RIPs) have significant performance issues with images that are rotated, scaled (especially in different % in X and Y dimensions) and cropped into small clipping paths. RIPs have some intensive mathematical transformations to output these images to plates/film at very high resolution (2400dpi/133lpi) – taking inordinate amounts of time to generate separations. Normally, the workflow is to ensure that all images placed into your layout are pre-rotated and scaled. With InDesign, by forcing an early change such as this you are losing the benefits of flexible, late-stage editing workflow. However, how do you solve the RIP time issue?
What I (and Matt) found is another “side effect” of the transparency flattener. Prior to applying a transparency effect, it pre-rotates, scales and clips images at print/export PDF time. Therefore, we can use the special “set the frame to 99.9% Normal transparency” technique to force an image through the flattener without changing the underlying image. (ref: InDesign 2.0: Printing Output Choices and Flattener Tricks (including force Greyscale export!)) It is important to apply the transparency on the frame. Where this really works well is in extremely large images.
The end result is a smaller file, that RIPs extremely fast. Contrary to popular belief – transparency can significantly improve RIP time.