a. She didn't know that I had seen some of her paintings.
b. She didn't know that I had seen certain of her paintings.
c. She didn't know that I had seen any of her paintings.
I think (c) is clear. But do (a) and (b) mean the same?
Could they be used if she knew that I had seen some of the paintings, but she did not know that I had seen certain other ones. She knew I had seen paintings A, B, C and D but she did not know that I had also seen paintings E, F, G and H. In other words, could either of these sentences be used instead of:
d. There were certain of her paintings that she did not know I had seen.