Okay, this is rather unsatisfactory. We have the objects with this certain effect, but that's really all that is to it. I do not think that the effect alone will carry the article, since people being absorbed into artwork is not truly novel.
One of my hugest concerns is how the SCP was identified. Egg tempura paint is hardly used nowadays, so there would be little opportunity for the anomalous effect to happen. If that is not reconciled, I find it difficult that the Foundation decides that the SCP is worth their time.
About the effect, here are some food for thought. When does the painting becomes 3D? Will it be 3D when it is painted on? Or once the painter finishes with the piece? Why does organic matter get sucked in and not the inorganic? Are microorganisms affected too?