Greetings!
I haven't a clue as to the origin of your handprint. Quite an interesting mystery. One thing I am sure of is that unless this print is being kept in a dark area, it is definately not ectoplasm. Ectoplasm is usually formed from the materializing medium and is highly sensitive to light, fading and dissolving within minutes of the appearance. If the print is still there, take a qtip smear sample and bring it in for analyzing at the chemists.
I've had the unfortunate circumstances to have experienced physical manifestational resiodues. Most samples that lasted were made up of a gelatinous protein base (like seaweed jelly) or smoke residue. Having lost ectoplasm in a sitting is not fun and can be painful and very dangerous...
I know that this really pushes the ole belief buttons but I'm skeptical of it being ectoplasm. I can see that it is there though. I love mysteries...Good Luck! (IMG:
style_emoticons/default/rolleyes.gif)