Traditional sketches are often appreciated more than digital ones. They seem more lively, more "real", and they have some kind of "soul". However, if you want to present your pencil art to a wider audience using the same medium as digital art—the Internet—you stumble upon one great problem. Any tool you use to convert traditional art into digital form will have some influence (usually negative) on its quality.
Adobe Photoshop comes to your aid! If you think that doing anything to a scan/photo is cheating, let me reassure you—whether you want it or not, the conversion itself changes your original picture. You can only leave it as (bad) as it is, or do something to bring it back to its traditional glory. Let's see how!
Digitize Your Traditional Art
I've created my picture using three tutorials:
How to Draw Animals: Horses, Their Anatomy and Poses—horse anatomy
Taking Flight: A Beginner’s Guide Into Drawing Wings—wing anatomy
Create a Flight Animation From Scratch in Adobe Photoshop—wing poses
A scanner is the best tool you can use here. It will give you "zero perspective", which takes away at least one problem. However, if you don't have one, use a camera. The bigger the resolution, the easier it'll be to achieve a sharp picture. Both ways will give you a digital file with the content looking nothing like your sketch.
1. Fix the Perspective
The bigger the picture, the harder it is to take a picture of it without any lens distortion. Let's see how to fix even the most extreme case of it.
Step 1
Place your file into Photoshop. Use the Crop Tool (C), hold Alt and Shift, and drag the borders away a bit to make the canvas bigger. This way we'll get more space for the transformations without scaling the picture down.
Step 2
Right click the layer and Convert to Smart Object. It'll let you transform the image multiple times without losing quality. Go to Filter > Lens Correction and switch to the Custom tab.
Here you can play with the Transform sliders to remove the distortion caused by the camera.
Step 3
The previous method has its flaws, so we need to add one more correction. In my case, the picture turned out too "squished" vertically. If that's also your case, right click the layer, Rasterize it, and then use the Free Transform Tool (Control-T) to stretch it to the proper proportions.
2. Remove the Colors
In many cases your black-and-white sketch will be turned into a mass of random colors, usually because of incorrect white balance. Let's fix it with one simple step.
Open the Window > Adjustments panel. Select Black & White.
It's done!
3. Remove the Messy Background
Smudges, dirt, uneven lighting—the background of your sketch is something you'd gladly say goodbye to. Let's do it!
Step 1
Add the Layer Mask to the sketch. Make sure your background layer is white, and if not, add it.
Step 2
Click the white rectangle next to your sketch's thumbnail. Use the Soft Round brush to paint roughly the area around the character. Remember: black removes, white brings back.
Step 3
Make the stroke smaller and work precisely on the edges, switching between black and white to get the right effect. The background is gone!
4. Fix the Contrast
Contrast is usually the one and only thing an artist changes before posting a scanned artwork. However, it's a far more complicated issue than it seems, and playing with the Contrast slider only may bring more harm than good. I'll show you how to manage it properly.
Step 1
Add the Levels adjustment.
Step 2
This panel shows you the histogram—a distribution of blacks and whites in the picture. A perfect histogram looks like a mountain with gentle slopes, but "perfect" doesn't mean the most desirable. The shorter (horizontally) the histogram, the higher the contrast. Drag the right slider to the left to turn light grays into white, and the left slider to the right to make dark grays black.
There's a trap here waiting for you. It may be very tempting to give rich blacks to your image, but take a look at your traditional sketch. Does it have rich, hard-edged blacks? If not, changing the histogram to get them will deprive the picture of subtle changes of grays. Remember: you want to make the digital sketch look as good as the original—not "better"!
Step 3
Sometimes, because of uneven lighting or smudges, some parts of the picture are darker than the rest. We need to pick them and change their histogram individually.
Use the Quick Mask Tool (Q) and paint over the area you want to change.
Press Q once again to go back into normal mode and invert (Control-Shift-I) the selection. Then add the Levels adjustment once again—it will be applied to the selection only. Play with the sliders until the element matches the contrast of the rest.
You can apply the same contrast to other parts just by clicking the mask (the rectangle next to the layer's thumbnail) and painting with white over them.
Step 4
The problem with the Levels editor is that it changes the shades evenly. There's a big chance your scanner/camera lost the finest dark shades, and they're very important for the final "feel" of the picture. You can't bring them back with the histogram, but there's another tool—the Curves editor.
This editor is a very powerful one. In fact, you could adjust the Levels here! Let's see what it is about.
By default, the lower left corner represents the darkest areas of the picture, and the upper right corner represents the brightest ones. By adding a point on the line and dragging it down you make the area it represents darker; by dragging it up, you make it brighter.
If you want to make the fine dark details darker, add a point near the "black" end and drag it down. The line is actually a curve, so you'll need to straighten (balance) it with other points. Feel free to play with it to get the effect you want!
If you do it properly, only the finest details will become darker—not all the grays.
5. Crop the Picture
This is the most intuitive part, but let's talk about it anyway.
When drawing traditionally, you are forced to work on the dimensions of the sheet of paper. Digitally, you are free to use any. When using the Crop Tool (C), pay attention to the "rule of thirds" grid and make it work for you.
6. Give It a Traditional Feel
There's one aspect of traditional-digital sketches that's mostly ignored. Paper has a texture—that's why your strokes aren't smooth lines, they're always a bit ragged. Your digital background, on the other hand, is perfectly smooth. It doesn't justify the ragged lines, making them look simply unclean instead of stylish.
Photoshop has a solution for this, too! First, right click any of the layers and select Flatten Image. Then go to Filter > Filter Gallery. Expand the Texture list and select Texturizer. Use the Sandstone texture with a subtle Relief and a proper Scaling.
Now the subtle texture in the background optically justifies the textured strokes. It's not just a fancy reminder that you've created it traditionally—it's actually a must, if you want to make it look as it did before digitalizing!
7. Prepare It for View
Last but not least, the huge file you've probably got after digitizing the sketch isn't what you're supposed to show to others. There's really no need to present all the 1 mm strokes in a form of 20 px! You don't look at the sketch by sticking your eye to the paper, so don't force others to do it.
The other advantage of scaling the sketch down is that the smaller the picture, the more detailed it looks (because of small gaps between the lines). Also, if your digital original was a bit blurry, scaling it down may help may reduce this effect.
To scale the picture down, simply go to Image > Image Size and type a width that is more appropriate. All the pictures in this tutorial are 600 px wide; 700-800 px wide may be a better choice for an artwork (depending on how detailed it is). Also, choose Bilinear for the resample method. Scaling (even down!) is never completely lossless, but choosing a proper method may prevent you from losing too much.
If the picture is scaled and still looks a bit blurry, go to Filter > Sharpen > Smart Sharpen. Play with the sliders to get a subtle sharpening. This filter is usually pretty useless when it comes to detailed, colored pieces, but it works miracles with pencil sketches!
There is no need to save the picture in the same format as your "digitizer" tool. Go to File > Save for Web to choose the best settings for your image. Most of the time you don't need to care about the size—just make sure the quality stays intact!
We're Done!
You can now proudly present your art online! Maybe these tricks weren't as simple as sliding the contrast up, but the effect is incomparably more attractive.
Do you know other tricks you can use to make your traditional sketches look better in digital form? Write a comment—you may help others!