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I've recently started graphite pencil drawings and would like to digitize my drawings. I've experimented with my document scanner (Canon Pixma MX 340) and my camera (Canon PowerShot G5 X Mark III). I am not really happy with either. Let me show a few examples.

With the scanner I get images like this one:

enter image description here

This is rather dull. I can let GIMP auto-adjust the levels to make it a bit better:

enter image description here

And then I can also reduce the gamma to 0.4 to make make it a bit darker:

enter image description here

This is okay-ish, but the stroke with the hard 4H pencil just get lost partially.

Compare this to the result from the camera, where I have adjusted the levels and converted to grayscale:

enter image description here

Here the stroke from the 4H pencil is all there. But one can also see a large amount of paper grain here because I took the picture at the window and light didn't come from the direction of the camera.

My theory is that the flatbed scanner causes metallic reflection in the pencil drawings and therefore they appear much lighter than they would without that reflection. I deduce that from a test I did with a charcoal pencil on the top and a super soft 8B graphite pencil on the bottom:

enter image description here

Without the reflection, both are pretty dark pictures. But when scanned on the flatbed, the pencil drawing on the bottom gets this metallic grey look.

I have the impression that the scanner works very well for charcoal drawings. But what is the best way to digitize graphite pencil drawings?

Martin Ueding
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  • In my personal opinion (which you don't have to share, of course) all your "high range" drawings look like anything but pencil. It looks exaggerated, like you want to make a clay figure look like a bronze casting. This can be a conscious choice if you want it to be "your style", or maybe you'll want to experiment with charcoal if pencil is not the right medium for what you want to achieve. – Elmy Jan 12 '24 at 05:47
  • @Elmy: I'm not sure I understand correctly, so let me try to say what I understood. So you basically say that I shouldn't try to map the darkest pencil shades to black because they are inherently grey. By trying to adjust levels/curves to get the dark parts to black, I am overdoing the contrast? And basically trying to make a graphite pencil drawing appear like a charcoal pencil drawing? – Martin Ueding Jan 12 '24 at 06:42
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    Yes, that's pretty much what I'm saying. To be absolutely clear: I'm not saying that you cannot / shouldn't do it. If you find you personal style in that filter, that's fine. However, if it doesn't work for you, maybe you're using the wrong tools. Either the wrong physical medium that cannot fulfill your wishes or the wrong digital process that cannot yield the results you want. You don't have to switch to charcoal, either. There are other black pencils that behave more like graphite but look more like charcoal. Maybe experiment with some options. – Elmy Jan 12 '24 at 14:57
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    Also, you don't have to limit yourself to just one type of medium. You could draw in pencil and add charcoal or black pencil for more contrast in your drawing before digitizing. You could experiment with layering first charcoal and adding graphite on top or first graphite with charcoal on top. I'm just throwing a few ideas around that might get you closer to your desired contrast before digitizing, so you won't depend on a digital filter too much. – Elmy Jan 12 '24 at 15:36
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    @Elmy: Thank you for all these pointers! I'll experiment with different pencil materials and different ways of digitizing. – Martin Ueding Jan 13 '24 at 10:02

2 Answers2

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What I usually do is photograph graphite drawings from an angle that has as little reflection as possible. An easy setup for this is to have the drawing lit from the sides by two or more similar lights (similar mostly in the sense of colour temperature, but, since we're working with "greyscale" images, this is not really a big concern), so you can point your camera at the drawing in-between the lights, and it won't reflect any of the light sources.
As long as you can eliminate the shadows in the grain of the paper - diffuser lighting will improve this as well - without having any rays reflected directly from a light source into the camera by the graphite, the resulting image should be a lot clearer.

A flatbed scanner does the exact opposite: it shines a light straight onto the drawing.

Another way is to have the graphite itself be less reflective, like spraying the drawing with a matte (workable) fixative.

Joachim
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    When photographing I'd either include the whole sheet of paper or place a rectangular frame around the drawing. That's to allow you to fix any perspective errors if the setup isn't perfectly squared up (perhaps handheld, lacking suitable hardware, or the only way to eliminate glare from ceiling lights you don't control - I photograph sketches in work, not that they're remotely artistic) – Chris H Jan 12 '24 at 06:38
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In the past, with good quality scanners, I've found it better to adjust the scanner's settings. That's because the sensor had more dynamic range than the file formats typically used. With more modern hardware and software, scanning to 16 bit TIFF would be a good idea. But with a lot of corporate multifunctional devices (primarily for printing and photocopying) you have to take what you're given, and I no longer have a scanner.

If it is glare/reflection, dynamic range won't help much, but it will do a bit

Chris H
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