Scanning pencil drawings

Pencils are perhaps the most common tool to draw - Scanning a pencil drawing however is usually a big mess! Some people even prefer to photograph their drawings instead. There are a bunch of guides and tutorials that help you to digitize and enhance pencil lineart. But it gets really complicated if you have a carefully rendered and shaded drawing with crosshatching or very thin and light strokes.

My scans had always the same problems:

  • Light tones are "swallowed"
  • darks aren't really dark and get messy when darkened with photoshop 
  • the midtones are extremely grainy.

Here is one fine comment with tipps and tricks. However, it didn't really help me with all of my problems. So I decided to test every part that influences the result:

  • The Scanner
  • The Drawing: The pencil & the paper
  • Enhancing and Saving

One has to keep in mind, that a screen with wrong calibration leads to loss of detail too. 

The Scanner

I've got an Epson Perfection v300 photo, wich is okay for the price of 100 €.

  • First thing to do: Use the most professional mode your scanner offers and disable all the automatic "enhancements" and "correction" options. You can do all the adjustments and contrast corrections much better in a graphics program.
  • Next you should check for HIDDEN configuration screens that have even more "automatic" options - Tiny buttons and tabs or device options in the Windows system settings for example (I overlooked a certain button for years...). On the left is with automatic color and light correction, right is completely raw. This seems to be the solution to the disappearing light tones. At the bottom is raw and enhanced next to each other and big.

  • A common advice is to use a very high dpi setting: I can't agree completely. The effect from 300 to 3000 dpi was so subtle that it didnt justify the scanning time of 50 minutes and a filesize of 1Gig. I think something near 1000 dpi works well enough. It might be more usefull if you have a very good scanner - you can see how blurry my 3000 dpi scan looks at 100% zoom (300 & 3000 both scaled down to 72 dpi):

  • Scan a grey wedge next to your image: Thats a clever trick, especially if you can not disable the automatic correction. If your scanner really scans raw images it should not have any effect:

The Drawing - Why pencils are hard to scan

Graphite pencils have features that arent the best for scanning to begin with:

  • reflective
  • cant reach full black
  • stays at the high parts of the paper grain only (when applied lightly)

That's why the image looks very grainy when scanned and enlarged. You can diminish the grainy effect by:

  • Use an Estompe / paper stump if possible to smoothen you image. It will rub the dust into the paper structure and even the tone

  • You can also draw more smoothly when using a very sharp pencil
  • You can try to fix the image with matte fixative spray. This can improve the tone and reduce the glossy graphite.
  • Dont use "sharpen" on the raw scan
  • Draw BIG! I did this mistake A LOT. When scanning with high resolution you will get a huuuuge image, you view your drawing "zoomed in". THATS why you can see the grain of the paper. The simple trick is to scale the image down (if it is intended for viewing on a screen). More on this later.
  • Try to get very smooth paper: layout paper is very fine (but a bit costly). I have a "Paperblanks" Sketchbook from 2004 with very smooth paper, but it seems they changed the paper for the newer ones.
  • Be aware that smooth paper is more reflective. If your scans look "overexposed" (= bright, clear white paper and light details dissapearing) try to get paper that is less reflective.
  • Some people have better results with toned paper.

 

Enhancing and Saving

There are almost endless ways to enhance the contrast of a scanned drawing. A pencil isn't black (75% Black in my test scan, Charcoal being 92% black), so you have to decide if you want to "stretch" the tones for a full tonal range or leave it "natural". Personally I always darken it a bit.

  • I prefer the "Levels" function of photoshop (or similar functions in other programs). You can tell by the histogram how your tones and contrasts are distributed
  • You can also try some "unusual" approaches, especially for clean lineart: Try to experiment with duplicated layers and different layer modes. You'll find a lot of tutorials about cleaning line arts online.
  • There are also many ways to influence the saturation (your paper is perhaps a bit yellowish, or your scanners light is a bit blue (like mine)). Since you have a pencil sketch without colours it's most easy to just drop the saturation slider in the Hue/Saturation Option.
  • As I mentioned in the last section: It's crucial to reduce the image size! If you look at it at 100% on screen it should be similar to the real drawing. The grainy parts will form a rather smooth surface again. If you want an image as big as your screen it's best to draw it that big. Reducing is very easy in Photoshop: Open the image size dialog, make sure the checkbox "Resample image" is checked and just change the resolution from very big to "96" ("Print size" does not change, "Pixel dimensions" will change) and the result should be approximately the same size as your original drawing. You will not get it 100% the same size, because it depends on your screen too.
  • Now, why not just scan it with a low resolution?

You see, it gets a bit sharper with higher dpi. You can notice how the 3000 dpi of my crappy scanner doesn't really "improve" the image any further, it just gets more blurry (Original in cm: 4,2 x 4,6 cm). I guess 1200 dpi is just fine for my scanner. Better scanners will probably have even better results.

  • You can now use unsharp mask to push the contrast. Use it AFTER the reduction, or you'll "enhance" the grain effect.

to be continued with adjustments and enhancing tests and a conclusion with an optimal image.