If the source file is not in the TIFF CMYK format, load the image normally with Load and then obtain the CMYK planes by using ColorSeparateCommand.
Paint the planes using PaintCmykPlanes.
To save the planes as TIFF CMYK, call SaveCmykPlanes. To save as another format, create a BGR Image using ColorMergeCommand and then save the image with Save.
The Image can be manipulated by manipulating each plane independently. Be careful when doing this. Some transformations should be done to all of the planes, while others should be done only to a particular plane.
For example, when performing a spatial transformation (flip, resize, rotate, etc), perform the same spatial transformation on all of the planes. Otherwise, there may be unwanted or unexpected results.
Other transformations should be done to a particular plane. For example, the K plane controls the amount of black ink. Changing the intensity of the K plane will darken or lighten the bitmap. Changing the brightness of one of the other planes will change the color rather than the image brightness. Be sure to study how the CMYK planes are combined to make the final image, in order to have a good understanding of what is needed to achieve a particular result.