A student of mine has submitted their exam paper with a large portion of text scribbled out beneath one of their answers.

This is what it looks like:

enter image description here

For context, their actual answer is written eight lines above this, meaning that it almost certainly isn't part of their answer.

This student is troubled and it is vital that I decipher what it is that they have written. It could either be something negative and/or threatening towards another student, myself or fellow teachers, or perhaps something altogether different, hence why I need to figure this out ASAP.

The reason I am asking about GIMP specifically is because I am using it on Ubuntu 20.04.

I am aware that the brightness and/or contrast levels can be adjusted in order to make certain portions clearer, but I am only able to make out four words at present.

Is there a good way to achieve this? I have also scanned hi-res versions of both the front and back of the answer in order to potentially extract it from either side.

Is there perhaps a better tool to decipher this?

  • Hi Welcome to GDSE. Levels/curves could have been used if there were some separation of the colours, but not if the ink is all the same colour like the example. There's probably nothing that could do that, not even Photoshop.
    – Billy Kerr
    Commented Apr 12, 2021 at 8:56
  • I feared that would be the case. I even considered that perhaps the indentation on the reverse of the page from the initial writing may have been raised more than the scribbled part, and thus could somehow be highlighted in some way relating to different (reversed) depth levels (and then obviously mirrored/flipped horizontally in order to be made readable),
    – Mus
    Commented Apr 12, 2021 at 9:00
  • Have a look online, do some research. There may be some AI driven forensic analysis possible, but I doubt it. In any case, this would be highly specialised work, perhaps something undertaken by intelligence or police forces.
    – Billy Kerr
    Commented Apr 12, 2021 at 9:06
  • I found this paper on the subject, so someone is definitely thinking about the possibilities of using computers to do this:
    – Billy Kerr
    Commented Apr 12, 2021 at 9:09
  • 2
    .. ask the student. Apologies, something just doesn't sit right with me trying to forensically decipher something which has been intentionally scribbled out. If you were able to "decode" it... and then approached the student, there may very well be a strong sense of invasion or betrayal. Which will not help a troubled young person. I think a conversation would be more useful. But, i'm not in the situation. I don't think this is really a design question.. but I understand the thought behind posting it here.
    – Scott
    Commented Apr 12, 2021 at 9:33

1 Answer 1


One difference could be the pressure on the pen (stronger when scribling) with more relief in the scribbling. Perhaps a raking light is enough for inspection with the naked eye otherwise taking a picture (of either side of the paper, possibly the opposite side if there is nothing on it) could provide a mask usable to dim the scribbling. A scan could be a solution since flatbed scanners also tend to increase relief with their light source on the side.

There is also the possibility that the student is clever and there is nothing under the scribbling and he just sound a fun way to make everyone waste time.

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