Stuck with spray painted wall

[MAKATTACKS]

Can anyone help?  I have am back in the crime scene - got the ultraviolet tool - got the hanged mans ghost to reappear - went to display the message on the wall that was spraypainted over in green and I can't get the gadget to work!  It says it needs calibrated. Have no clue how to do that!  PLEASE HELP!

[wilco64256]

Where did the paint on the wall come from? There's something in the scene that can help you figure out how to calibrate the tool.

[MAKATTACKS]

Thanks.. but I should have said that I found the numbers on the green spay paint... but can't figure out how to calibrate the tool?  Is there a function I am not aware of possibly? Thanks so much!

[MAKATTACKS]

I could not figure out the logistics of calibrating the light gadget.  I finally figured it out - click the hand on the inventory display, then click the gadget and key in the numbers....