Thank you all for the comments.
Since it was mentioned, the background was pitch dark, not too much light there and a 1600 ISO plus the haste to push the button. Couldn't qualify for a FS anyway. More so since the painting was smaller and I needed to make it larger; artistic license
Interesting light! But I have a feeling that the background was heavily darkened (apologies if I am wrong, Mariuca!), so it probably would not work for the FS