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Ever had a ballpoint pen that would all of a sudden hit a 'dead spot' on a sheet of paper and refuse to write? It's clearly not the pen, because when moved off to the corner it would draw perfect circles instantly. Move it back to the spot, and it stops working again. Usually I can get something blotchy if I write out the word a dozen or so times while pressing hard. What's going on with the paper and ink here?

Some pages of my notebook are like this and it's very annoying. My best guess is that it got splashed and something about the paper changed, but my guess probably isn't a very good one since it doesn't have the signature crinkly waviness of wetted paper.

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    $\begingroup$ Perhaps the paper is really smooth at that spot to the point where there isn't enough friction to 'turn the ball point'. $\endgroup$ – LordStryker Apr 10 '14 at 17:52
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If in doubt, try it out.

I just spilled some olive oil on a sheet of paper and wiped it off again.

Result: The ballpoint pen does not write on the oily spot.

Did you fat-finger the paper?


EDIT

The experiment above confirmed the finding in the question but didn't give an explanation.

Actually, two hours later it is still not possible to write on the oil-soaked and more transparent parts of the paper with a ballpoint pen, while a felt-tip pen (here: an Edding, ther German equivalent to a Sharpie) leaves perfect lines on every part of the paper.

Paper is fibrous material with a porous structure - without that and the capillary effects coming with it, fountain pens wouldn't be able to write on it.

For ballpoint pens, this probably isn't so important - the ink is very viscous.

But paper also has a rough surface - and this might be crucial, as already suggested by Lord Stryker in his comment. The rough paper surface provides friction, allows the tungsten carbide ball to roll, take up ink and spread it on the paper.

On a smooth or slippery surface - and this seems to be the case for the oily regions on the paper - the tip of a ballpoint pen only slides but does not roll. As a result, no ink is transfered to the paper.

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  • $\begingroup$ I suggest another experiment: usually when you write a lot, your fingers and the side of you palm sweats and becomes fatty. Just try it on a piece of paper with a pen that has such a problem, that you strongly rub your finger against the paper, and then you can't write on it with the pen. The only solution is found is that I put a piece of anouther paper under my hand while writing. Not every pen has such a problem however, there are pens that can quite well write on fatty/oily paper, I wonder what the reason to that might be. Probably the ball is more loose and turns more easily. $\endgroup$ – user3237992 Jan 10 '17 at 10:04
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The reason is, when you start writing on the top.. it is quite good, it does not happen but when you move at the bottom it starts, right? It is due to your sweat and oils your body release due to humidity and heat and other reason would be keeping your book open for a long time under the influence of the atmosphere. what you can do to prevent it, is.. use a piece of paper below your palm and don't leave the book open for a long time.

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