I have throughout this exchange been polite, I quite understand that it might be a bit more work for you to calculate the per channel black levels if the margins are odd values - but throughout you have REFUSED to explain why you made this change. Why won't you explain your reasons?

And if you think I don't understand something - then please tell me I'm wrong and WHY.

This change delivers nothing but pain for me and my users, and so far you still haven't explained why you did it. As for you suggestion that I need to learn more about raw file processing - I use LibRaw so I don't have to know everything there is to know about that.

I have interpreted your statement that having odd margins causes incorrect calculation of per channel black level caibration to mean that it results in LibRaw incorrectly calculating the cblack array. Have I misunderstood? If not why does this not work if you use the image CFA and image data, or if you use the "All Black" pixel array in the margins, can't you just use the appropriate CFA that matches the full frame as compared to the one that applies to the user image area.

If you would prefer that this discussion took place offline, I'm very happy to do that.

Thanks in advance