in the art gallery
The scream. it is on the top middle level next to the forgery detection lab.
falsification
If you're talking about in counterfeit island, then after you get that job, you go into the forgery detective lab and finish the two "stations" there.
you put the paintings in a rotational order going left. then, go to the guy up stairs and you go in to the forgery dectection lab.
This is called a fake, or a forgery.
A counterfeit coin is often referred to as a fake or a forgery.
The police discovered a forgery ring producing counterfeit documents.
You go into the forgery detection lab, complete them then talk to the guard at the front doors. When you are done, go back down to the docks where you met the mysterious guy.
In the Forgery Detection class, you only have to examine the three signatures to identify which one is fake.
The magnifying glass is only used in the Forgery Detection class on Counterfeit Island.
Once you have correctly solved the switched-paintings challenge, you go to the Forgery Detection Lab in the Museum. You have to complete the tests to get the Supply Room key. (see related question)
alpha rays