When you draw a stroke with a drawing tablet, your stroke will not be perfectly smooth. There are many causes for it any many things you can do to address it.
The tablet and driver are components that can contribute to strokes that aren't as smooth as you would like
All tablets have a degree of diagonal wobble that can appear in your stroke.
Tablet sometimes exhibit a little bit of "noise" in their stroke. This noise is similar to wobble in that it deviates from a smooth line, but it does so in a more random way.
The surface of a tablet may be too smooth and this can cause the pen to easily "slip" away from your intended path.
You are user and your drawing style can affect the smoothness of a stroke
Your hand and arm and way of moving them over the tablet can cause imperfections in your stroke.
Drawing slower is more prone to introducing errors into your strokes.
Consider how you hold you pen. Different techniques of holding your pen can affect how smooth your strokes are.
Brad Colbow - How Pros Hold a Pencil 2024/05/28
Using a digital; pen on a very smooth tablet surface can result in the pen feeling "slippery" as you draw. And so the pen often seems to "slide away" from the intended path of the stroke you are trying to make. This is a common complain for iPads because an iPad's surface if very smooth glass.
Consider buying a protective sheet to increase the surface texture a bit. See: protective sheets.
Another way of increasing the surface texture and avoiding a slippery feeling is to use a felt nib. Many tablets now come with felt nibs, though they may not be installed in your pen by default.
Many people draw just by moving their wrist. Try instead drawing by moving your shoulders more.
Usually someone's hand can draw a smooth stroke easier at some angles than at others. For example, if you are right handed drawing a strong from bottom left to top right is easy but drawing from top left to bottom right is harder and the stroke less smooth. Rotate the application canvas so that you accommodate what your hand is better at doing.
Some people find that drawing a stroke toward themselves is easier to keep smooth than drawing away from themselves.
Generally speaking a faster stroke will result in a smoother stroke.
Occasionally some people enable mouse mode in their tablet driver. Mouse mode uses relative positioning and usually makes it harder to make a consistent stroke. Instead try disabling mouse mode.
If you are using a pen tablet, mismatched aspect rations between your pen tablet and your monitor will distort your strokes and make it harder to draw smoothly. Make sure you check for this and correct it. More here: Matching aspect ratios.
Please do check for this. Many people have been using their tablets for years with mismatched aspect ratios and when they make the ratios match it is a BIG DIFFERENCE in their ability to draw strokes correctly.
Use zoom to your advantage. The stroke is affected several things which are physical in nature. For example, a diagonal wobble may introduce a 1mm wobble as your draw. If you are drawing with your canvas zoomed out then 1mm accounts for a lot of pixels. If you zoom in more then the 1mm accounts for fewer pixels of wobble. So you can really minimize some effects my zooming in as much as possible for your stroke. This minimizes the effect of those disturbances and also forces you to draw with a longer stroke which itself will minimize errors.
Precision mode is a temporary change in how the active area of the tablet is mapped to your desktop. When precision mode is engaged, your entire tablet active area is mapped to a small region of the desktop. This means you have to make very large physical gestures on the tablet to create smaller strokes on your displays. That has the effect of making it easier to smoother strokes.
Use brush smoothing in your applications.
Krita, under Tool Options, has 4 different brush smoothing options: None, Basic, Weighted, and Stabilizer.
Clip Studio Paint has several options
A setting called Stabilization that goes from 0 to 100. Where 100 adds the most amount of smoothing possible.
You can also separately use the Adjust by speed setting. It has two options: Increase stabilization when drawing slowly and increase stabilization when drawing quickly.
Some apps like Clip Studio Paint have the ability to "fix" strokes after they have been drawn.
The advantage to this technique is that it doesn't slow down your stroke as you draw.
The disadvantage to this technique is that you don't exactly know the path of your stroke until a moment after you draw the stroke. Also if you draw a sharp corner, post-correction techniques can somethings not recognize the corner and instead show it as a smooth corner.
Applications like Krita also support vector tools. If you are having problems with smooth strokes with you pen, the vector tools can produce perfectly smooth strokes.
Some applications, like ProCreate on the iPad, have a a shape detection feature. Roughly speaking after you draw a stroke and hold you pen still for a moment, it will recognize a line, or circle, or curve and create a perfect smooth version of your stroke.
Almost all drawing tablet send pen tilt data to the computer. Wacom consumer tablets are the notable exception.
Assuming your tablet is sending tilt, data you may want to have to tilt control what you draw. This document explains how to configure your application so that it can take advantage of tilt
First, make sure your tablet drivers are installed typically these will be necessary to take advantage of tilt.
Here is an example of how to configure tilt in Clip Studio Paint
A simple example is the Calligraphy brush in CSP
Open up the brush settings then go to brush size
Click on the arrow pointing up at the end of brush size
A dialog called Brush Size Dynamics will open
There are four checkboxes controlling what will control the brush size
Disable everything and enable tilt
NOTE: it's not required to disable everything , but it just makes it easy to see how tilt is affecting size if only it is enabled.
Then once the brush is configured you should see tilt affecting the size of the brush
After that you can look at other brush settings and get tilt to affect other properties of the brush.
The tablet sends "tablet reports" to the computer at somewhere around 200 reports per second. Each report contains information like pen position, pressure, tilt, button info, etc. More here: tablet reports. A brush engine's responsibility is to take that information and use it to draw a stroke in a drawing application.
In a creative applications that draws strokes - applications such as clip studio paint, krita, or photoshop, there is a component (or set of components) we can refer to as the brush engine
Among its responsibilities is to take this pen data and combine it to draw a stroke.
Your drawing apps typically feature different brushes: pen, pencil, watercolor, etc. You could think of separate brush engines for each kind of brush. In reality a single brush engine may handle multiple kinds of brushes.
But what all these brush engines have in common is that they transform the pen data in various ways to affect how the brush works.
Typically these are the ways in which a brush engine can control the stroke
stroke opacity
brush size
brush rotation
And there are lot of other settings
Here is an example from Clip Studio Paint 2.0 for its Calligraphy brush
Here is an example from Krita
If you are in a creative application that draws strokes,
The most common mapping of pen input to stroke is how pressure is handled. Typically, pressure is either:
pressure -> ignored - it has no effect on the brush. this is common for very simple brushes
pressure -> brush size - more pressure gives a bigger brush
pressure -> brush opacity - more pressure gives a more opaque brush
Tilt typically is treated like this:
tilt -> Ignored
tilt -> brush size - for example a pencil brushes may get wider as the pen is tilted to simulate how a real pencil makes wider marks on paper as it is tilted.
tilt -> brush rotation - enabling the tilt to orient the brush shape
In Clip Studio Paint, smoothing is called Stabilization. The Stabilization setting found under the brush's Tool property > Correction options.
If you don't see this setting click on the little wrench icon at the bottom right of the Tool property palette and you then can see the option, set it, and make it appear in the brush's tool property palette.
In Krita, under Tool Options, use the Brush Smoothing options