Raster data for Pure black text printing

[shermin]

Hi,
 cupsColorSpace in ppd file is mentioned as CMYK and if i code walk through the pstoraster source,i came to know that the cups_map_rgb(Map a RGB color value to device colors) is called first which inturn calls cups_map_cmyk().Why cups_map_rgb() is called first??

What I understood is that all the color values should be treated in the basis of RGB,gray or DeviceN and in the case of color device,cups_map_rgb() is called first to generate the C M Y K colors and from those CMYK separation is called.

Whether my understanding about the pstoraster source code is correct or do i need to do more in code walk?

Shermin