The following savePDFAsMultiplePageTIF sample illustrates how you can create a multi-page TIFF from a multi-page PDF loaded in an igDocument. In the following sample we use ImGearSavingModes to control some raster options like bit depth and scaling (to control resolution):
In the following sample we use an alternative approach to the one above that uses global control parameters to control some raster options like bit depth and resolution: