How to remove the black grid from pictures done with black-gridded papers?

Suppose I draw with grid -paper, I want some automated way to remove the grid fast. I have earlier used the magic-wand tool in Gimp but it is not really robust and now looking some good solution for batch-editing. The hack of changing the paper will work but I am looking here to automate the grid removal with ready works done with black-grid -paper. How can I automate the removal?

I originally planned Imagemagick but the problem fits better SO, you need to adjust positioning not just cropping. It can be actually quite hard programming challenge requiring pre-positioning etc at the start (paper may be direct etc odd practical challenges). Perhaps the easiest way to solve this programmatically is to remove all lines of certain color, here though a bit challenging because scanning not perfect. Other tools may also work. I moved the programming aspect of this question here.

Solution -candidates so far

• 1.0. Programmatically: see here for SO -thread.
• 2.0. Paper: change paper

• 2.1. color -grid

• 2.2. whitelines -grid-paper
• 3.0. tracing tool such as potrace or Vectormagic.com
• 4.0. sketching board with high-intesity light with gridded background
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As an alternative to possibly unnecessary editing I would say, draw into a plain white paper. Perhaps if you need the grid, keep it below your actual white paper that you draw into, so that you can scan it without the grid. Drawing tablet would be one solution as well. –  Joonas Jul 5 '12 at 6:26

This does not solve the current problem but may help to solve future problems. Model -photographing use different color -palettes, colors not usually occurring in nature. I am not sure how to use them with grid -paper but below some keywords.

• 5.0. Unnatural colors
• 5.1. blue-green -screen
• 5.2. red-green -screen
• 5.3. green -screen
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Use tracing tools such as potrace with low-amount-of-details, to hide the less-strong grid lines. There may also be an option to remove the grids by removing all colours of certain type -- so if your grid were red, there is probably some easy programmatic way of removing red things with white things.

This hack is errorsome and requires some Gimp's erasing of things and then tracing with tools such as Vectormagic.com or Potrace, more here. The idea is that you guide the tracing/vectorizing detection algorithms by removing just some parts of the grid. Strong lines with clear pattern will be visible with option low amount of details. The good side of this solution is that it requires no programming skills but sometimes slow adjusting of tracing options and interesting result that may need manual repairing.

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This does not solve the problem with your ready works but a solution candidate for the future works. I think the programmatic removal of grids is the best option for your ready works then some filters to make it more blurry or vectorize it.

Use sketching board with black-grid at the back of the paper, some high-intensity light and different paper such as draft paper or white paper so you can see the grids.

(Source of the image here, Creative Commons Attribution-Share Alike 3.0 Unported license.)

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Bit late to do this, but in future you can make this a lot easier by drawing in black over a colour grid, or vice versa.

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I'm a big fan of whitelines grid paper for drawing. The grid lines are much less obtrusive, and it's really easy to make them disappear completely after scanning with a little manipulation of levels or curves. Great simple idea. They do isometric paper too. –  user568458 Jul 5 '12 at 9:10
Interesting - so that's a white grid on a pale background? –  e100 Jul 5 '12 at 9:32
Exactly that: pale grey paper with white grid lines. The grid is really clear when you want to pay attention to it, and easy to ignore when you don't. It's also designed so that the grey and the grid disappear in photocopying, which also makes it really easy to remove after scanning - you can do it in the scan settings. –  user568458 Jul 5 '12 at 11:37