Often, especially if there are pages with images that spread across the spine, it is not ideal to creep (or shingle) by shifting pages into or away from the spine. In these cases, the best solution is to scale the pages horizontally. As far as I know, the only commercial software that allows this is Preps. It would be great to see such a feature available in a "value-for-money" application like Imposition Wizard.
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