I use an action that creates 4 layers -
Color Balance
Hue/Saturation
Levels 1
Levels 2
The action also includes 2 Luminosity Masks on the two levels layers, Levels 1 will have a mask for the shadows, and the adjustment darkens these in the image, Levels 2 will have a mask for the upper third of the bright tones in the image, and the adjustment brightens these slightly. I add +6 saturation with the Hue/Sat layer, and add Cyan, Yellow and Blue with the color balance layer.
This is just a base to start with however, and I adjust each image individually before importing it into a custom template, adding text and flattening to a finished image of the correct dimensions ready to import into Booksmart. Most of the time all that is needed is a slight change to one of the levels layers and a slight change to the color balance depending on the image. You can then switch quickly between original image with proof view off, then image with adjustments and proof view on to compare your changes in tone and color. The most common problem that needs correcting I find is an image with lots of warm tones, or an image with lots of greens or blues.
I have only just completed all the work for my first book, so haven't got a printed version back yet to test how accurate my proofing is. I suggest using the B3 program they have, as this provides a more recent color profile to proof with than the HP Indigo one available, although it does cost slightly more to print using B3.
My book will hit the printers this week, so I will post back with the results sometime soon...
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