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I made a drawing, scanned and everything, but the remnants of my sketch (blue) have popped up and the lines of my final drawing are too indefinite. I want a solid black final drawing and the blue ghost must be removed. How do I fix this in Photoshop?

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Here's an inverted image, if it helps somehow.

I inverted the colors so you can see what I'm talking about

  • Yes you can. To give the best method I'd need to see what the lines and paper look like though. Can you edit your question to include a picture – Ryan Feb 23 '17 at 14:52
  • I added the picture, is not the blue lines, is the black lines. They aren't even – castro Feb 23 '17 at 15:07
  • What does "have the color off" mean??? I see varying shades of grey/black and blue in every line - which is pretty standard for a hand drawn scan.. what is "off"? Please be more specific. Thanks. – Scott Feb 23 '17 at 16:29
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Create a new layer. Fill it with White. Layer → Layer Style → Blending Options. At the bottom is a Blend-If section. Pull the left side in on the bottom one that reads Underlying Layer:

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Create another layer. Fill it with Black. Do the same thing but from the opposite side:

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Now you're basically done:

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If you want to clean up the edges I would just go to the original drawing and use Gaussian Blur. You'll be able to see it adjust as you go. Might want to duplicate it or convert it to a Smart Layer first so its less permanent.

Before Blurring close up:

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Gaussian Blur:

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Now I would take a final step and combine all of those layers into one Smart Object and do a second, much smaller gaussian blur. The first one was below the adjustments so it remained solid black. This one is above those adjustments so what we're doing is adding some nice anti-alias to it:

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Which gives you the final result:

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Clean up line art

I have a nice simple trick for cleaning up line art. This only works if the image doesn't contain smooth gradients but only black lines and filled black areas.


Convert your image to grayscale (Image/Mode/Grayscale). It should look like this:

grayscale

Scale up your image 400% (Image/Image Size). Make sure to choose Bicubic Smoother.

scale up

Press OKand you will have this:

scaled up

Now, convert the image to bitmap mode (Image/Mode/Bitmap):

convert to bitmap

Resulting in this:

bitmap

Convert the image back to grayscale. Let's clean the jagged edges a bit using Filter/Noise/Dust & Scratches:

dust and scratches

Which will give us a little cleaner result:

less noise

Now we are almost done. In Image/Image Size, scale down the image to its original size (25%). Again, make sure to use Bicubic Smoother.

scale down

The result should look like this:

done

You might need to experiment with individual settings on different originals. Your image might need a little Brightness/Contrast before going through the process - you need to make sure that anything you want to be black must be more than 50% black - anything less will become white.

Remember to always scale up and down by a factor of 4 or more. If you scale it less you might get unwanted pixelation.

If you have many images you might want to make this into an action.

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  • Using a threshold adjustment is probably a better idea than just straight converting to bitmap – Cai Feb 23 '17 at 16:46
  • @Cai, I see your point. I guess it is a matter of taste. In my experience, I have more control if I use curves before "bitmapping" instead of just adjusting the threshold. Sometimes I even use both, but most of the time the trick just works with 50% threshold so it was just to keep it simple. Another thing is that I often keep line drawings in 1200 ppi 1-bit, because I like the crispness on print. – Wolff Feb 23 '17 at 18:20
  • Interesting approach. Although in this case the result has the edges too jagged compared to the other solutions – Luciano Feb 24 '17 at 10:06
  • @Luciano, you're right, but the jagged edges come from the original, not from the method. I should have increased the radius in "Dust & Scratches" and/or fine tuned the curves layer more. Maybe even added some blur before converting to 1-bit. – Wolff Feb 24 '17 at 21:51
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At first the brighness range must be stretched to 0...255. Strict BW by treshold can lose too much information, so we use the curves tool.

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Your photo is quite noisy. Much of it is JPG artifacts due too high compression. The noise must be cured at first, because all later processing makes the noise more difficult due its effect to the process. The noise can be reduced by Gaussian Blur; 2px is enough. Another possible filtering is the Median filter.

Before:

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After Gaussian Blur:

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The background and the blue ghosts can be deleted. The blue color of the ghosts makes the cleaning easier. Selection by Color Range is good for this. You must +pick colors from the background and minuspick colors from the wanted line until the quick mask (=red) covers the wanted lines. The fuzziness slider should be around the half.

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The background practically vanishes by pressing DEL:

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The line is far from solid black. Invert the selection (Select > Inversion) and fill the selection with the black by using the paint bucket. Remove the cross from Anti-alias because it causes overflows. Have the treshold =128 and flood 2 to 4 times over too light line areas until the black is deep enough. A little half-tones should be left at the edges to reduce the jagginess.

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Here's the final result:

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