Resource ID Numbering(IM:XP)

Inside Macintosh: QuickDraw GX Printing Extensions and Drivers /: Chapter 6 - Printing Resources / About the Printing Resources

Resource ID Numbering
You assign a unique identifier, or resource ID, to each resource that you use in a Macintosh program. The printing resources that you define for printing extensions need to be in a certain range: from 0x9600 (-27136) to 0x97FF (-26625).
The printing resources that you define for printer drivers need to be in a certain range: from 0x9400 (-27648) to 0x95FF (-27137). For most of the printing-specific resources in your drivers, you define the ID as a value added to a constant named gxPrintingDriverBaseID (-28672), as in this example:
resource gxOverrideType (gxPrintingDriverBaseID+1, sysHeap,
                                                   purgeable)
{
   {
   gxRasterPackageBitmap, segmentID, firstOffset+40,
   gxRasterLineFeed,    segmentID, firstOffset+44
   };
};
QuickDraw GX defines constants for the resource ID of many of the resources that you define for your extensions and drivers. These constants are described in the reference description for each resource.