Types of Line Art
Smooth Line Art
This type of lineart is probably one of the most well-known of all, if not most-used. You can see it being used in cartoons, comics and graphic design. The lines do not have any texture, and they do not look squiggly.
Organic Line Art
Organic lineart, just as the name suggests, consists of lines that have a more organic, natural appeal. They often imitate traditional mediums and are textured. Much more line variation is present.
Sketchy Line Art
While it is often avoided as the concept of a "sketch" is often perceived as "unprofessional" and "unfinished", this method is also a valid way of doing line art. Your guidelines could be showing and there could be incomplete lines. As long as you know when and where to keep things clean or clarified, you could still end up with a look that is much more professional than smooth lineart.
What You Could be Doing Wrong
1. Lack of Stroke Confidence
Yes, it is quite stressful to make that "perfect" stroke that will match your sketch layer underneath. However, using timid and short strokes will cause your images to look flat and indecisive, alongside making your lines look hairy (unless this is a stylistic choice, avoid it). This is a major reason why sketches often look better than lineart. When you sketch, you have more confidence in your lines since you do not have the pressure of making it look “perfect”. You need to carry the same confidence into your lineart.
Even if your style does not use smooth line art, it is important to develop stroke confidence. Remember that before you can break the rules, you need to learn them. Otherwise, the viewers can sense that you do not have a full grasp of what you are doing, and yo will not be able to branch out and explore different styles.
How to Fix it
Do the opposite- use longer strokes! With digital art, you have the privilege of undoing your actions. Most of the time, your lines will not turn out the way you desire. It is very normal. Just undo and redo until you are satisfied with your work. Make sure to use shoulder movements for the big strokes, and turn on the stabilizer if you want a smoother look.
Of course, it is easier said than done. You could try practicing line confidence by opening up a blank canvas and filling it in with random strokes. Try to use your shoulder for longer strokes, then switch to wrist movements, and switch back and forth.
2. Ignoring Volume
When doing line art, artists often focus on the "line" part too much and ignore the fact that lines are in fact representative for how we perceive forms and planes. This inevitably causes drawings to look flat and disoriented.
When volume is ignored, the viewers are distracted by the lack of consistency in the forms and they cannot understand what the perspective is or how exactly something is shaped. Therefore, it is very important to not have a linear mindset. Again, this sense of flatness could be used for certain styles but it needs to be done carefully and purposefully so that it can be read as a stylistic choice and not lack of artistic skills.
How to Fix it
Remember to always think about forms and continuity when doing line art. The lines that you are drawing are not random, and have a purpose that you need to fully understand. If you are drawing a line to indicate the existence of a tendon, for instance, the tendon needs to follow the entire anatomical structure of where it is. Otherwise, it will look like the lines are randomly floating in a plane.
In the example given on the left, you can see that the clothing takes the form of the body into consideration and wraps around cylindrical shapes. The wrinkles also follow the flow of the clothing material, making them look a lot more natural.