If someone wrote something down on a piece of paper with a standard HB pencil and then erased it, would there be any way for forensic investigators to ever recover or find out what was written? (Assuming that the pencil wasn’t pressed down hard enough to leave a physical imprint on the paper, that is). Would microscopic traces of pencil lead still adhere to the paper, and if so, would this be enough to reproduce what was actually written?
Does it depend on the paper or the type of pencil? No, I’m not planning to do anything illegal, I’m just curious, but it seems to me that once it’s erased, it’s gone for good. Then again I’m sure there are a few experts here who will prove me wrong…
Almost any writing has pressure enough to make indentations on the paper. Even if those are illegible, there are other ways of recovery.
Think about what they did with the Dead Sea scrolls and other ancient documents. Under an electron microscope, they can pick up traces of inks and pigments which are much too faint for the human eye to detect.
I guess it all depends how much determination (and how much funding) the investigator has.
It’s easy to erase so that the eye can’t detect anything, but hard not to leave any trace at all. Graphite is fairly greasy, which is why it works in the first place, and why it is used to lubricate locks.
Some will adhere and be detectable with the correct microscope or xray.
For at home use, many faint images can be brought out with a scanner and photo touchup software.