Each open image in ABBYY FineReader Engine, each image in the so-called "internal format," is represented by the ImageDocument object, which includes 4 image planes. One image plane corresponds to one Image object:

• Black-and-white plane
• Gray plane
• Color plane
• Preview

The detailed description can be found in "Help" → "Guided Tour" → "Advanced Techniques" → "Working with Images".

Note: Internal ABBYY SDK image format is not supported by 3rd-party image viewers. You cannot modify the image in ABBYY internal format with 3rd-party software, save it and reopen in FineReader Engine.