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Translating the position of the pen on the EMR sensor (AKA “the digitizer”) to a position on display is called mapping.
The tablet firmware reports the position of the pen on the EMR sensor using coordinates that are relative to the EMR sensor.
The tablet driver takes coordinates from the tablet and then maps them coordinate on the display.
The simplest case to consider is a pen display. In this scenario the EMR sensor is directly underneath the display and both are inside the plastic shell of the tablet
In this case the active areas physical size and aspect ratio matches that of the display perfectly.
and in this case the transformation is very simple because the EMR sensor and the display have the same aspect ratio.
this is a somewhat more challenging case.
Because the EMR sensor and the display in the monitor need not be the same size and need not have the same aspect ratio.
But still it is possible to transform the coordinates from the tablet to a coordinate on that display.
This is a little bit of a weird case. But we have to account for it because so many people have multiple monitors with their computers.
Tablet drivers allow users to handle the situation in multiple ways.
The tablet driver can map the EMR census coordinates to a single display.
Another option is that the tablet driver can map the sensor coordinates to a virtual coordinate system that includes multiple displays.
As a rectangular region, we can discuss the size of the active area in different ways
Width & Height
Diagonal length
Area
But most often we will talk about active area sizes using the diagonal length.
If you need help picking the right size for your tablet, consult choosing the right tablet size.
You can often see the diagonal length in the names of pen displays. For example:
Wacom Cintiq Pro 27
Huion Kamvas Pro 16 Plus 4K
For pen tablets, manufacturers often use descriptive names such as "small", "large" instead of numbers.
Wacom Intuos Pro Medium
Wacom Intuos Pro Large
By looking at the Wacom's product line and naming, we can establish a decent framework understanding how descriptive words like "small" and "large" map to numbers. Note that the size names are different for pen displays and pen tablets.
If we look at how drawing tablet models are distributed along this scale we'll see that there is a lot of variation.
Is it reasonable to use the active area's Diagonal length vs the Active area's area measurement.
I think it is, because the diagonal is reasonably well correlated with area for drawing tablets.
Let's see how diagonal and compare buy plotting the values for 180 different tablets.
For pen tablets:
And for pen displays:
Overall, I think using the diagonal is reasonable.
The aspect ratio of your drawing tablet's active area, can have a big impact on how good it feels to draw on them.
Any rectangular area has an aspect ratio. Which is the relationship between the width and height. Usually we will express the AR as a ratio like 16:9 or 16x9.
Displays (monitors) tend to have aspect ratios like 16x9 and 16x10. 16x9 is the most common aspect ratio.
If you are using a pen tablet, it mostly likely does not match the aspect ratio of your monitor and you will see some distortion when you draw.
This will make give you a weird and unpleasant feeling while drawing. You can fix this by forcing the aspect ratios to match. More here: Matching aspect ratios.
The active area of a pen display and their display panel inside the pen display are equivalent. So they always match.
As of 2023, NONE of Wacom's pen tablets have an exact 16:9 aspect ratio.
The active area of a drawing tablet is the rectangle region of the tablet's surface that detects the EMR pen. Some drawing tablet manufacturers (Wacom & XP-pen) use the term active area while others (Huion) use the term working area.
When we talk about the "size" of the drawing tablet, we are referring to the active area.
The active area is usually marked in some way on the surface. Sometimes it is marked at its four corners. Some tablets show a grid of of dots.
The active area of a pen display is very easy to detect because it is the exact the same area of the display panel.
Usually when we discuss the size of an active area, we talk about its diagonal length. Drawing tablets vary quite a bit in their active area size. More here: Active area size.
The relationship between the width and height of the active area is its aspect ratio. More here: Active area aspect ratio.
Pen tilt information is always sent from the tablet to the tablet driver and from there to the operating system and then to pen-aware applications.
Sometimes when drawing it can be useful to turn off tilt. There are options
Drawing apps that use brushes may let you control how tilt affects the brush. So, you can configure specific brushes to ignore tilt. Examples of applications that support this are Clip Studio Paint and Krita.
Turn off tilt in the driver - SOME tablet drivers let you simply turn off tilt so that it isn't reported to your operating system or applications.
XP-Pen drivers have this feature.
Pressure is the physical force being exerted on its tip. Remember that it is the pen that measure the pressure, not the tablet surface.
The Initial Activation Force (IAF) is the smallest amount of pressure that an EMR pen will detect and report. The maximum pressure the maximum amount of pressure that an EMR pen can detect and report. The pressure range is the range of physical force the pen is capable of sensing and outputting as pressure. In other words its lower bound is the IAF and its upper bound is the maximum pressure.
A wide pressure range is very desirable. It contributes a lot to a good pressure experience. A wider pressure range is even more important than the number of pressure levels.
A lower IAF is good because it allows you to draw finer details better.
To get a broad view into how different pens handle IAF and max pressure, consult this document:
Some people REALLY need that EXCELLENT IAF of <1gf.
Others like (myself included) work fine with a 3gf IAF. I definitely notice the difference but it doesn't effect me with the kind of art I create.
These days tablet brands say that they can handle 8K (8192) levels of pressure. Some tablets even claim to support 16K pressure levels.
Don't get caught up in hype about pressure levels.
Pens - even if they are of the same model - differ a little in their pressure sensitivity
Pressure sensors are subject to wear. Over time, you may find that a pen is less sensitive to pressure than it used to be. Though in practice, I have never experienced this in any noticable way myself.
There are two techniques. The techniques have two things in common:
The pressure is measured by the pen.
Then transmitted to the tablet.
The modern technique: the nib contacts a pressure sensor inside the pen. The nib goes through the hollow ferrite rod and then the nib touches the pressure sensor deeper in the pen. The ferrite rod does NOT move. The pen digitally encodes pressure data into the electromagnetic signal generated by the inductor coil. The tablet then decodes the digital pressure information from the signal.
The very old technique: Nib goes into the hollow ferrite rod but does not come out the other side. The nib is shaped in such a way that it is firmly embedded in ferrite rod. Ads the nib moves, so to does the ferrite rod. The movement of the ferrite rod changes the resonant frequency of the inductor coil. That change in frequency is then sensed by the tablet and translated to pressure.
Almost all drawing tablets can detect the tilt of the pen. The support tilt for drawing tablets usually ranges from 0 degrees to 60 degrees.
Think about how you use a pencil - when you want a fine line you keep the pencil more perpendicular. However, when you want a wider line - maybe you are shading in an area - you tilt the pencil.
Many drawing applications have digital brushes that mimic that same behavior.
For example, here is a stroke I drew with Krita. I configured the brush to ignore pressure entirely, but to let the amount of tilt control the width of the brush.
As draw left to right I started with the pen very perpendicular and gradually started tilting the pen.
Mapping tilt to brush width is just the most common way of using tilt. However, depending on the application you could have tilt control other attributes of the stroke.
For many years now tilt has been a common feature on drawing tablets. And today the vast majority of tablets support tilt.
However, Wacom seems has traditionally included tilt only on its professional models. In particular tilt is NOT supported in these entry-level Wacom tablets:
One by Wacom Small (CTL-472)
One by Wacom Medium (CTL-672)
Wacom Intuos Medium (CTL-6100 & CTL-6100WL)
Wacom Intuos Small (CTL-4100 & CTL-6100WL)
The vast majority of drawing tablets have tilt support, but a few entry-level Wacom ones do not.
For some people tilt is critical and for others, it is not useful at all. It strongly depends on what they are doing.
whiteboarding -> tilt not useful
taking notes -> tilt not useful
educational videos -> tilt not useful
digital painting with natural media brushes -> can be very useful if you would like your brushes to respond to it.
line art -> can be useful but many people do line art without using any tilt features
The standard range is +/- 60 degrees for both X and Y directions
I don't know of any tablets that support a wider range
Even if your tablet is sending tilt data to your computer, your application may or may not be using the data.
Some applications don't use the tilt data at all. An example would be most note taking applications like OneNote. They tend to recognize pressure but not tilt.
Other applications do recognize tilt but the use of the tilt data is only for specific brushes. So for example, typically a "pencil" brush would support tilt. But other kinds of brushes may not. Even then, these brushes has settings that let you customize whether and how tilt is used for the brush.
Here's a good example for a brush in Krita. You can seee that the Rotation of the brush is set to the Drawing Angle, but that it could also be set to the tilt.
To calculate the location of the pen, the tablet must take into account how much the pen is tilted. This process is called tilt compensation. Remember: no tablet has perfect tilt compensation and at extreme title angles you might see some deviation - This is normal.
The bezel of a drawing tablet is essentially all the area on the surface of the drawing tablet that is not the .
For many devices such a phones and TVs, people make a big deal about having the smallest bezels possible. For drawing tablets, it is good to have a wide bezel.
Avoids your pen uncomfortably "dropping off" if you are making strokes near the edge of the active area
Provides a place for you rest your wrist or forearm so that the edge of the tablet is not digging into them.
The EMR sensor (digitizer) needs to be a bit wider than the active area so that it is still accurate at the edges. A wider bezel provides that extra space for the digitizer.
I claim you only need 2048 levels of pressure (and probably even less than that). As a quick example watch this 35 second video:
Sometimes it is useful to disable pen pressure. For options on how to do so go here: .
You don't need to know these details, but if you are curious how an EMR tablet actually detects the tilt of the pen go here: .
You may not always want to have tilt affect your drawing. It is possible in some cases to disable it. More here:
Before you read this section it would be good for you to read: pen pressure response. This document won't make a lot of sense without you understanding clearly what a pen pressure response is.
A pressure curve is essentially a little bit of math that transforms a pressure response to another pressure response. In more everyday terms a pressure curve creates a new pressure behavior for the pen.
Most often, we see the results of this transformation shown to us visually in driver or application UI.
For example in the Wacom Tablet Properties app it looks like this:
The X axis labelled as "Pen pressure" is the logical input pressure
The Y axis lavelled as "Output" is hte output logical pressure
This particular curve bends down a little. But many other shapes are possible. Each shape has their uses.
It is important to distinguish the pressure curve from the pressure response because they describe different things completely.
A pressure response describes the pressure behavior of a pen - and this is a description of physically happens in the world. It relates physical pen pressure to logical pen pressure.
A pressure curve is an abstract mathematical entity that transforms logical pressure values. A pressure curve is completely arbitrary and does not describe a relationship in the physical world. It is a purely logical construct.
So often in documents and YouTube videos you might encounter people describe the pressure curve as the pressure behavior of the pen. This is completely inaccurate. The pressure curve describes how the pressure behavior (the pressure response) is being modified. You cannot look at a pressure curve and understand the pressure behavior of your pen. The only way for you to understand the pressure behavior of pen is to physically measure it with the scale and start mapping physical pressure values to logical pressure values.
There are a variety of pressure curve shapes - each of which can solve some problem or achieve some visual effect.
To see which drivers and apps support witch shapes see this: Curve support in applications
Details on specific shapes
Based on my analysis of pen pressure ranges, I have developed this simple rating scale for IAF and max pressure. This represents my initial thinking and I expect to revise this in the future based on feedback.
For more general information about pen pressure go here: pen pressure
Consider this diagram to be a DRAFT. it will evolve as I learn more.
I think the pressure categories here (EXCELLENT, VERY GOOD, etc) are reasonable.
But be aware, that for a specific pen there can be significant differences for IAF and max pressure for individual units.
Manufacturers
From tablet experts such as Kuuube
And my own measurements: https://1drv.ms/x/s!Aml8i4Jd6crCkTerfXD_1zsIxg3A?e=2aCPfI
Pens, even of the same model, vary in how their pressure handling
Drivers can potentially affect IAF.
Comments on pen pressure levels and ranges for Wacom products: https://www.reddit.com/r/wacom/comments/10l0ujb/comment/j5u1v3z/?utm_source=share&utm_medium=web2x&context=3
Comparison of minimal gram-force ("initial activation force"/"initial activation pressure") recognized by various digital pens and digitizers ( https://www.reddit.com/r/stylus/comments/opc44f/comparison_of_minimal_gramforce_initial/)
Initial Activation Force / Initial Activation Pressure Cintiq Pro 16 2021? (https://www.reddit.com/r/wacom/comments/v9989o/initial_activation_force_initial_activation/)
The null pressure curve is the most important pressure curve - exactly because it does nothing. We can apply the null pressure curve to any pressure profile and it will not shift the profile in any direction.
The definition of a null profile is a pressure curve function that takes the input logical pressure and returns that very same value as the output logical pressure. In order words f(p) = p.
If you take the range of input logical pressures which range from zero to one and plot them on the X axis of a chart. And then you apply the null pressure curve to those values and plot the result of the function on the Y axis - then you get a straight line at 45° that goes from the lower left corner to the upper right corner of the chart.
Anytime you see a chart like this it clearly identifies that null pressure curve. And you can be sure that it does not do anything to a pressure response.
And the chart above you can see there's been no change because the orange line which represents the pressure response after applying the curve has exactly the same shape as the original pressure response.
We encounter pressure curves in tablet drivers and in creative applications. These kinds of applications often use the null pressure curve as the default value for any pressure curves they have. This isn't always true but it is a very common thing to see.
If you're ever trying to solve some problem with the pressure of your pen the knowing about the null pressure curve is useful. Because it might be that somehow your pressure curve was modified and is affecting your pen. So a very common troubleshooting tip is to make sure that your pressure curve has been reset back to the null pressure curve. This way you can be sure it is not affecting what is going on
Besides drawing, pens have varying support for specifically erasing things. Typically this is done either with an eraser on the pen or using the pen buttons to perform the erasing.
Below you can see the nib and the eraser for the Wacom Pro Pen 2 (KP-504E). As you can see the nib is quite a bit larger than the nib.
The eraser is also pressure sensitive and retracts into the pen. The eraser has a much bigger retraction distance than the nib.
Erasers are relatively uncommon for EMR pens.
Drawing apps have to add deliberate support for erasers. Some do have support. Some do not.
Lots of people do use the eraser and find it critical, but then lots of people never use the eraser. I'm one of the "never use" category.
For me flipping the pen around to use the eraser feels like it disrupts my flow and sometimes I simply am too clumsy and I have dropped the pen while I was rotating it. Also I just think it is faster to use a keyboard shortcut or to use my tourbox device.
Remember that a specific tablet is compatible with only specific pens. Avoid buying a pen that has an eraser and assuming it will work with your tablet. Always check with the manufacturer.
Another option is to map the side buttons to switch to the eraser tool in the app you are using. You can do this in the tablet driver app.
Not all pressure curve shapes can are possible in all cases.
Drivers usually offer only simple pressure curves
Applications are generall very flexible
Ultimately a pressure curve is a mathematical function that takes input logical pressure (p) and returns an output logical pressure (p’)
that is it maps logical pressure to logical pressure. The logical pressure comes in as a value between zero and one, and the output is a logical pressure between zero and one. The specifics of the mapping of the input to the output are completely arbitrary and we can make pressure curves do whatever we want.
In reality we wouldn't just have one pressure curve function with a single input logical pressure parameter like that. More typically we'd have a pressure curve function that accepts multiple parameters. By tweaking these additional parameters we can control what the pressure curve is actually doing in a dynamic way.
Smooth changes to physical pressure should produce smooth changes to the pressure readings from a a tablet. When this is done well I use the term "pressure transition stability".
An unstable transition would mean that smooth changes in physical pressure would produce exaggerated or wild swings in the pressure readings. I call this "pressure transition instability"
No pen is perfect, but most are pretty good. However, it is not uncommon to discover a pen that has problems with these pressure transitions. Usually it happens in the lower range of pressure.
These unstable readings may not be visible if pressure used to alter the size of small brushes - for example 5px or 10px. So to see the behavior we need to scale up the effect by using larger brush sizes - for example 300px.
NOTE: Your hand itself will introduce imperfections in a stroke. So it takes some practice to learn how to distinguish the effects you are causing, versus what is happening with the tablet.
Compare the three cases below. The example on the far right has noticeable "pulsing" effect which is a common way this instability shows up.
Overview
Typically, a pressure curve function takes input logical pressure values in the range of [0,1] and maps it to values in an output range of [0,1]. This means that the full output range is used.
Some curves can limit their output range to achieve better control over brush strokes.
The easy way to tell that a pressure cuve constrains the output range is to notice that the curve shape does not reach to the bottom or to the top of the pressure curve graph. Two examples are below.
Even though the shapes look a little diffrent, they both effectively take the input logical pressure values between [0,1] and map that to an output region close to [0.3, 0.6]
Imagine the user's brush setting is 100px and the brush is set to change its size in response to pressure. Then suppose the user draws a stroke that goes from the IAF value to the MAX physical pressure.
The stroke size is computer like this:
With a null pressure curve - The stroke width will go from a size of 1px to 100px.
With a the curves shown above - the stroke width will go from 30px to 60 pz. So the widht of the stroke does not vary as much.
Helps give you more consistent brush strokes while still allowing some variability
By avoiding the lower end of output logical prerssure, you can have your strokes start off a little thicker than normal. (Though there are other ways some apps have of accomplishing this goal.)
Here are two examples of curves that ignore input.
IGNORE BOTTOM - ignores the lower end of logical pressure
IGNORE TOP - ignores the upper end of logical pressure
IGNORE BOTTOM
Effectively this increases the perceived IAF of the pen.
This is useful in several cases:
Your pen might be drawing while hovering and this is one way that might help that problem
Some people don't want the pen to draw when in contact with the tablet, the only want to use it to point. They can ignore pressure to help make this happen.
IGNORE TOP
Some people have issues with their hands and with pens that have a very high pressure range they can never get to the full maximum pressure. They can use IGNORE TOP to effectively lower the maximum physical pressure.
Pen tracking is the tablet's interpretation of the physical position of pen.
Pen tracking accuracy is how close the the operating system cursor (mouse pointer) is to the physical tip of the pen.
Note that this accuracy must be measured without taking into account the effect of parallax
Also this must be measured when the pen is NOT moving - because pointer lag by definition causes a kind of dynamic inaccuracy
Perfectly accurate pen tracking means the tablet thinks the pen is exactly where the physical tip is. Any deviation from that is an inaccuracy.
However, all tablets are slightly inaccurate.
Pen tracking accuracy is a concept that applies to both pen tablets and pen displays.
However, in practice it is only really an issue with pen displays. This is because with pen displays you can see the inaccuracy - which shows up as the operating system pointer being offset from the tip of the pen.
If your pen's position is not matching where the pointer is in a major way especially if it is happening across most of the tablet, then may help.
The pointer is generally a bit more offset from the tip of the pen toward the edges and especially the corners rather then the main part of the screen.
This offset in the edges and corners is totally normal. Some tablets have more and some have less.
Tablet manufacturers (except for Wacom) often publish their official corner accuracy numbers. Here are some typical values I've seen.
±3mm
±1.5mm
±1mm
If you have a pen display and it seems to exceed what the manufacturer says it has and you are disturbed by it, you should contact support.
For myself, generally even if I see ±3mm it isn't really a problem because I am not drawing in those areas. But of course, it does look weird and I would like it always to be more accurate and do prefer ±1mm.
Wacom
This is a partial list of Wacom's more recent pens.
Wacom Pro Pen 2 (KP-504E)
Wacom Pro Pen Slim (KP-301E)
Wacom Pro Pen (KP-503E)
Wacom Grip Pen (KP-501E)
Wacom Art Pen (KP-701E)
NOTE: Wacom's most recent professional pen, Wacom Pro Pen 3, no longer features an eraser.
Huion
Huion PW600
Huion PW600S
XP-Pen
XP-Pen P06
XP-Pen X3 Pro
The nibs of drawing tablet pens can be made of different materials. The most common nib material is plastic or felt. The vast majority of pens, by default, have a plastic nib pre-installed.
The reason for different materials is that they greatly impact the sensation of "texture" you experience.
Plastic nibs generally feel smoother when drawing on a given surface. Some of the surface texture will get transmitted through the plastic nib.
Felt nibs provide a little more friction and many people say it can make a tablet surface feel more like traditional paper.
I always suggest giving felt nibs a try, you may enjoy how it feels.
Both kinds of nibs wear over time and the amount of wear depends on how "heavy-handed" you are. But these materials are a little different.
Plastic nibs wear down less.
Felt nibs are more prone to wearing down. Also if you drop your pen and it hits the nib, sometimes I have found that the felt nib can be more easily damaged.
Wacom offers three materials for this pen (standard, elastomer, felt). See this video for an explanation of how standard, elastomer, and felt feel: https://www.youtube.com/watch?v=APAO-yWc_PY
I DO NOT recommend using a metal nib.
For a more general introduction to lag, see Lag.
If you you are "painting", there is a separate kind of lag called brush lag.
With the Apple Pencil the iPad has lag but the overall perceivable lag is very low compared o an EMR drawing tablet. I suspect the lower lag is due to some of these factors:
Very tight and optimized integration between the pen subsystem and the operating system. It makes sense Apple can do this because they own the entire tech stack.
in a normal drawing tablet the EMR pens have a coil that is detected by the tablet and that coil is deeper inside the pen while the equivalent Apple Pencil component is close to the tip of the pen and thus to the tablet. This smaller distance should result in less electromagnetic interference. In turn this should require less position smoothing to remove the interference which then shows up as reduced lag.
Relating to the previous point about distance. Just based on the visual parallax it seems like there is less physical distance between the tip of the Apple Pencil and the display panel compared to other EMR-based pen displays I have used. So, again this should reduce the amount electromagnetic interference and thus require less smoothing and result in less lag.
From some things I've read, the iPads do some position prediction with the Apple Pencil so that results in an reduction in lag at the cost of reduced accuracy with abrupt changes in direction. I've even seen one video showing that iPads also can predict contact with the surface of the iPad so that they can start drawing just a moment before physical contact is made.
YES - in theory and to some degree. But it is not a trivial thing to do.
Pointer lag comes from two sources: The tablet firmware and the tablet driver
It's possible to get rid of the lag caused by the driver by using a third party driver - for example OpenTabletDriver.
I've tried this with both an Intuos Pro and a Cintiq Pro. My results here
Intuos Pro - Noticeable reduction in lag (at the cost of a little more imprecision in the tracking of the pen)
Cintiq Pro - slight reduction in lag. But mostly stays exactly the same. From that I think the Cintiq Pro lag is primarily caused by the tablet firmware - probably to deal with the electromagnetic noise caused by the embedded display panel.
The pointer lag in the firmware cannot be removed because essentially it is impossible for a user to modify the tablet firmware.
All drawing tablets have a slight texture on their surface. The amount of texture varies quite widely. And people have strong opinions and preferences about it.
Pen tablets - the tablets without a screen - have various amounts of texture on the surface based.
Some tablets like the Wacom Intuos Pro (PTH-860, PTH-660, PTH-860) are known to have a lot of texture compared to older Wacom professional pen tablet models.
The consequences to a lot of texture is that it can wear down your nibs fast - especially if you are making lots of strokes over and over.
Also depending how much you are using the tablet, you may see over time that you will wear down the texture on the tablet. You'll mostly see this as regions where the tablet will look smooth or shiny. Despite the unattractive look, it doesn't intefere with using the tablet. The pen still feels like it has enough texture so it isn't a slippery feeling like an iPad.
Some tablets like the Wacom Intuos Pro (PTH-660, PTH-860) have a surface that has a replaceable textures.
These texture sheets can be very hard to find in 2023 - and they aren't cheap - but they offer two advantages:
You can get a texture more like what you want. Wacom offers them in Smooth, Standard, and Rough variants. Standard is what with the tablet out of the box.
If you damage your surface you can easily replace it.
Again, this is an incredibly rare feature for a pen tablet and only specific models of Wacom professional tablets offer this capability.
All pen display I know of have a little bit of texture.
The texture will either come from:
a matte film (that film is also usually providing an anti-glare treatment also)
an etched glass surface (the etched glass also provides an anti-glare treatment
Note that the anti-glare treatment stops the display from being glossy - but it also introduces some thign called anti-glare sparkle: https://docs.thesevenpens.com/drawtab/technotes/anti-glare-sparkle
Apple iPads
The surface of any Apple iPad is very smooth glass. Many people feel that using an Apple Pencil on an iPad screen feels "slippery". The pen seems to easily unintentionally "slide" as they draw because there is so little friction.
No drawing tablet by default has a texture that comes close to the feeling of paper.
There are some options that can increase the texture. In SOME cases they may give you something close to that feeling of drawing on paper.
You can buy protective sheets that you can stick on top of the surface of you drawing tablet which will provide the texture. More here: protective sheets.
Also you can use felt nibs - if they are available for your pen. These felt nibs also can provide some extra texture.
That means the tablet knows the (x,y) location of the pen precisely on the active area of the tablet.
The pen does not even have to touch the tablet. As long as the pen is close - about 10 mm typically - to the active area and within the bounds of the active area, the tablet knows the pen's position. This position detection without touching is typically called "support for hover".
That means that a mouse does not know its exact position on your desktop. The mouse has no idea what surface it is in contact with. In a general sense a mouse only knows that it is moving in relation to some surface.
The mouse does not now its location. The mouse only knows about changes in position - i.e. either it is moving or it is not moving.
The mouse reports this movement as a change in x position and a change in Y position (dx, dy)
What happens if you simply keep a pen or a mouse perfectly still and don't move them at all.
Drawing tablet will continuously report the (x,y) position of the pen.
In theory a mouse will report (0,0) indicating no movement. In practice mice don't even report the (0,0) because that data doesn't provide any interesting information to the computer.
One of the ways absolute and relative positioning really stand out is what happens when the input device jumps from one location to another
With the drawing tablet if you hold your pen let's say at the bottom left of the tablet - that means the operating system pointer will also be at the bottom left of your display. If you then pull the pen straight up and away from the tablet so that the tablet does not sense the pen's location and then you move the pen to the upper right hand, then suddenly the operating system pointer will suddenly appear at the upper right hand corner of the display
For a mouse if you try the equivalent thing something different will happen. If the pointer is at the bottom left and you suddenly pull the mouse away from the surface and then place it anywhere else, then you'll see that the pointer does not move.
Drawing tablets can simulate relative positioning when talking to a computer. This is called mouse mode. More here: Mouse mode
To work, a drawing tablet pen requires a little power. Either a pen will get power from the tablet wirelessly (Passive EMR) or the pen will use a battery (Active EMR). For a many years now, tablets exclusively use Passive EMR pens.
Passive EMR refers to the EMR technology where tablets wirelessly power the pen. All modern drawing tablets use Passive EMR. Their pens get their power just be being close to the tablet (about 10mm). The pens don't have a battery that needs to be recharged or replaced.
Wacom has been using Passive EMR for many decades. For non-Wacom table brands, they made the transition to Passive EMR with the last 10 years.
In contrast, Active EMR is when the pen is powered by an internal battery. The battery is either replaceable or rechargeable. If it is rechargeable, then the tablet will come with a special cable that plugs into the pen and then usually to a USB port on your computer for charging.
Passive EMR tablets can only be used with Passive EMR pens
Active EMR tablets can only be used with Active EMR pens
If you have have an older Active EMR pen, you cannot replace it with a Passive EMR pen.
All drawing tablets detect the position of the pen - even if the pen is not touching the tablet.
If you think about it, this is how the tablet MUST work, because the EMR sensor (aka the digitizer) is below the surface (plastic or glass) that the pen touches. So, obviously the pen is always detected at a distance.
This explains why we are able to place a sheet of paper or a plastic cover over the tablet, and the pen will still be detected correctly.
You can reposition the pointer without drawing or clicking.
You can see where your drawing stroke is going to be before you start the stroke
For some art styles it is very important: https://youtu.be/ZpcKfipVy24
This is rare, but a small number people don't like seeing the pointer move as they move the pen over the surface of the tablet.
The maximum distance the tablet can detect the pen is about 10mm for a modern EMR tablet.
Even though the typical hover height is 10mm, The EMR sensor itself can detect the pen at a much greater distance. For example, even around 20mm. But the greater the distance, the less accurate the the pen can determine the position of the pen. So for this reason tablet drivers enforce a lower max hover height.
Drivers from tablet manufacturers offer no user control over the maximum hover height. The height locked into the code of the driver. However, OpenTabletDriver does have plugins that let you control the hover height.
With a drawing tablet Hover is an intrinsic part of how the tablet works. There is no way to disable hover. Though in some apps it might be possible for you to hide the pointer when you use the pen which might achieve a similar effect.
Pen tablets require minimal amounts of power. They get enough power from a normal USB 2.0 port.
Pen displays require much more power than a pen tablet due to the embedded display panel. They may have a power adapter that you need to plug into the wall. Or they may be able to be powered with through a USB-C cable.
Pen tablets that have wireless support have built-in batteries that can usually last the entire day and do recharge quickly when they are plugged back in.
Pen displays DO NOT have batteries. They must get their power from a cable that is either attached to a computer or to power coming from a wall.
For some occasions and for some people they would prefer if a drawing tablet pen behaved more like a mouse.
For this reason drawing tablet drivers offer something that is called mouse mode.
Drawing tablets are absolute positioning devices. But enabling mouse mode will make them behave like a relative positioning device like a mouse.
Learn more here: Absolute versus relative positioning
Mouse mode is implemented in the tablet driver has no effect on the tablet hardware.
The tablet continues to use absolute positioning internally.
The driver takes the absolute positioning information it receives from the tablet and then translates that into relative positioning data when it sends data position data to the operating system.
In theory it shouldn't affect the quality of drawing.
In practice, it depends on what the driver is exactly doing.
Here's an example of the Wacom driver vs Huion driver in Krita on Windows.
As you can see the Wacom driver creates very jerky position data when mouse mode is enabled. It does not have to be like this, they could do better like Huion does.
Also, this difference is not due to hardware. I tested the same Wacom tablet with OpenTabletDriver also set to mouse mode (OTD calls this "Relative mode") and the lines were smooth.
This section is incomplete
XP-Pen (ver 3.4.7): Enabling Mouse Mode loses pressure sensitivity on Windows
Wacom: TBD
Huion: TBD
On Windows, Mouse Mode in some drivers may disable Windows Ink
You may need to restart an drawing application if you change the mouse mode setting.
In Wacom Tablet Properties app, select your pen, navigate to the Mapping tab, then under the Mode area you will see a setting you can switch between Pen and Mouse
Once you enable mouse mode, you'll see some new configuration options.
In the Huion driver, click Digital Pen, then enable or disable Mouse Mode at the bottom
Some drawing applications may get confused if they are running and mouse mode is switched on or switched off. So you may need to restart those apps.
Sometimes you will see that a driver does not have a mouse mode option for a pen display. The reason for this is probably that it would be somewhat unusual and a little bit unnatural to use append display in this way.
Barrel rotation is very easy to understand. It's just a rotation of the pen along its long axis.
In the diagram below, barrel rotation is indicated by the arrows that go around the long axis of the pen (as indicated by the dotted line).
Barrel rotation is a very rare feature on pens. I know of only three pens that support it.
Wacom Art Pen (KP-701E)
Wacom 6D Art Pen (ZP-600)
Apple Pencil Pro
Keep in mind that these pens only work with specific tablets. You cannot buy these pens and assume they will work with the tablet you have.
he pressure response of a pen describes the behavior of a pen with regard to pressure.
The pen measures of physical force at its tip. Information about the physical force is sent to the tablet and then translated into a logical pressure value. The pressure response is the relationship between that physical pressure and the logical press.
In numerical terms it can be expressed as a simple set of data points. And if we graph those data points with the physical pressure on the X axis and the logical pressure on the Y axis - then we get a chart that visualizes the pressure response.
All pens come out-of-the-box with a specific pressure response. And keep in mind the response is unique to each pen. The response even for pens of the same model will differ a little bit at the very least.
One thing that is generally found among EMR - is that the shape of the pressure response is bowed up quite a bit.
If we need to change the pressure response of a pen. We have to apply a pressure curve.
A pressure curve modifies a pressure response. You could think of it as creating a new pressure response. In the example above the pressure curve that we apply to the original pressure response has created a new pressure response which is much more linear.
I like to think pressure responses and pressure curves as a game of resource allocation - where we are trying to the physical pressure range in useful ways across the logical pressure range.
The reasons we want to think about this allocation intentionally is because it can give us three potential things:
a better drawing experience
we might be able to solve problems while we're drawing or even address or mitigate some hardware problems
and also it's a way of getting some creative effects four our brush strokes
This pressure response is similar to that of a Wacom pro pen 2 (KP-504E). It has that typical bowed up shape. The one thing that separates it from many other pens pressure responses it goes extremely far on the X axis because it has an extremely wide pressure range.
There are two interesting things about how physical pressure is allocated in this specific pressure response.
For the purposes of this discussion I'm going to only talk about how pressure affects the width of a stroke. Simply because it's easiest for me to visualize that in this document. But for everything I'm saying it equally applies when for example pressure is mapped to opacity or even to color.
The first is the shape of the response indicates an under allocation at lower physical pressure. About only 10% of the physical pressure range is allocated to about 50% of the logical pressure range.
This means that small changes in physical pressure result in big changes in logical pressure. In turn this means that there are big changes in the width of a stroke.
This can make it feel like it's hard to control the width of your stroke when you're drawing very lightly.
At the higher end of this pressure response we encounter an over allocation of physical pressure to logical pressure. About 50% of the physical pressure range is allocated to only about 10% of the logical pressure range.
This means that big changes in physical pressure produce small changes in lot pressure which produce small changes in the width of a stroke.
This can make it seem like you're pressing very hard but you aren't seeing your stroke size increase or decrease by much.
In general I think we would want a more even allocation of physical pressure range into the logical pressure range. The visualization of such a more evenly allocated pressure response is one that is much more linear.
To be clear I am not saying that linear is the best shape for a pressure response. I'm just saying it's a good starting point. Ultimately you'll have to use pressure curves to change your pressure response into something that works for you.
Here you can see how a specific pressure curve takes the original pressure response and shifts it to a more linear shape. I'll show you this example just to help illustrate how much you might have to bend the pressure curve to get a linear response.
And keep in mind again that the pressure response shown is for specific pen. This pressure curve may not have the same effect on different pens.
Some of Wacom's Pro Pens are so sensitive, Wacom by default configures pen pressure curve in the driver to have a small "deadzone" at the lowe end of pressure. This means the very lowest pressure readings are ignored.
Here is a screenshot showing that pressure deadzone in the default pressure curve the Wacom driver uses for the Wacom Pro Pen 2 (KP-504E)
Resources
Devid Revoy - Calibrating stylus pressure (for Krita) https://www.davidrevoy.com/article182/calibrating-wacom-stylus-pressure-on-krita
Pen pressure information is always sent from the tablet to the tablet driver and from there to the operating system and then to pen-aware applications.
Sometimes when drawing it can be useful to turn off pressure. There are several options
Drawing apps that use brushes may let you control how pressure affects the brush. So, you can configure specific brushes to ignore pressure. Examples of applications that support this are Clip Studio Paint and Krita.
In some applications you can completely flatten the pressure curve. This allows you to have the pressure report. This means the pressure is constant and will not result in the brush changing due to pressure.
SOME tablet drivers let you simply turn off pressure so that it isn't reported to your operating system or applications.
XP-Pen drivers have this feature.
In order to correctly represent the position of the pen. The tablet has to perform something called tilt compensation. This means adjusting the pointer position, depending on how much the pen is tilted.
This is very important for EMR tablets because the digitizer is sensing an inductor inside the pen. And that inductor is not close to the tip of the pen. It's deeper inside the pen.
Some other pen technologies. For example, the apple pencil don't have as big a separation as EMR tablets have.
Now no tablet does tilt compensation perfectly. I have seen some very old habits to do this very badly almost as if they don't compensate for tilt at all. But these days, a modern EMR drawing tablet does a decent job compensating for tilt. And so the pointer doesn't really shift too far away from where the tip of the pen is. But there is some variation. Some tablets are better at this than others.
When you press down on the nib they travels (or retracts) a little bit into the pen. This is NORMAL. If the nib didn't travels at least a little, the pen would not be able to detect pressure.
How much the nib travels depends on the specific pen involved.
The general consensus is that most people don't want too much retraction because it "feels funny" to use the pen.
A typical nib travel distance for Wacom's pens is about 1mm.
Diagonal wobble is a regular displacement of the tablet's interpretation of the pen's position.
You might also see this referred to as: "jitter"
I covered wobble extensively in this video on pen display accuracy (https://youtu.be/M4rEk_RNBrM)
If you slowly draw line on a tablet WITH A RULER the wobble will be apparent on diagonal lines. The diagram below exaggerates the wobble
The wobble can happen with any kind of pen movement - straight lines, or curves.
As the name suggest, the wobble is apparent with the pen is moving at an angle.
A 45 deg angle exhibits the most wobble
A 0 deg or 90 deg angle exhibits no wobble.
Angles between 0 and 90 exhibit more wobble as they approach 45 degrees.
The wobble is just more obvious with straight lines even the the same amount of wobble occurs with curves
Generally the wobble will be present the slower the pen is travelling
Some tablets exhibit the wobble even when moving the pen fast. This is less common.
Diagonal wobble is present in all drawing tablets in varying amounts.
There's no clear pattern by price or by brand or by device type about when wobble appears.
The wobble is NOT due to the nib wobbling in the pen.
The nib can be perfectly fixed in the pen and you would still observe the wobble.
In any case, remember that the nib is not what the tablet senses to detect position, but rather the inductor coil deeper inside the pen.
The wobble comes from the tablet and how it senses the pen position.
The wobble is due to how the tablet senses and interpolates the pens position.
The wobble is present in multiple digital pen technologies
The wobble is present with EMR pens
The wobble is present with non-EMR pen technologies such as MPP, AES, and the Apple pencil.
If there is wobble, it tends to show up at slow speeds. This is a bit expected.
If the wobble shows up at faster speeds, that is unusual.
Tilt could affect the wobble.
Most often I have not seen tilt have an affect on wobble, but I have tablet where an extreme tilt angle (an angle that would not be used in drawing) causes a massive wobble. I haven't tested all my tablets at extreme tilt, so I am not sure how common this is.
All tablets have wobble.
But for most, you would only notice the wobble when TRYING to find the wobble. In other words, it won't affect your normal drawing.
The real problem comes when the you notice the wobble creating alterations to the strokes that you didn't intend.
It also depends on what you are doing. You might notice wobble more if you are doing line art but not notice it at all if you are using an airbrush.
OPTION 1 : Turn on smoothing
Applications have different brush smoothing options. Explore those to see if they eliminate or reduce the wobble.
OPTION 2 : Zoom in
Try zooming in on the canvas in (for example by 2X) and drawing the same stroke. The wobble will technically still be there but because it is a happening on the physical moment of the pen, if you zoom 2X with the canvas in it will have 1/2 the effect on the stroke.
OPTION 3 : Draw a faster
Wobble is often something that occurs when you are drawing slower. Try drawing the stroke faster, in most tablets this eliminates the wobble.
If your strokes are small and drawing faster would cause you to have less control, then try zooming in more. This will make your physical stroke longer, but keep them the same size on the canvas.
OPTION 3: Use vector tools and brushes
Instead of drawing your stroke manually, if your application supports it, use vector strokes.
These are my wobble samples across a number of tablets.
https://1drv.ms/f/s!Aml8i4Jd6crChTjTXo89k5jO8mb8?e=t3ijPC
All were created using my a standard testing process: Diagonal wobble testing.
Some recent models with XP-Pen feature some excessive diagonal wobble. This is something you should check into when looking into these models. Here are examples of of the line wobble in recent XP-Pen:
XP Pen Deco LW 8:06 in this video : https://youtu.be/0VaH-UTRL7A?t=486
XP Pen Artist 16 (GEN2) 7:04 in this video: https://youtu.be/0VaH-UTRL7A?t=486
XP Pen Artist 12 (GEN2) 5:45 in this video: https://youtu.be/O6OzBT7BLsA?t=345
ExpresKeys is a Wacom-specific term, but people use it in general additional inputs for any tablet. Drawing tablets often have additional "inputs" such as:
Buttons (both physical and capacitive)
Dials
Touch-sensitive strips
Huion calls these buttons "Press Keys"
Some people love using these kind of inputs, but some people do not like them because either they
take up space on the tablet
are accidentally triggered
or their workflow just doesn't benefit from them
For these cases, you should be aware that these inputs can often be configured in the tablet driver to "do nothing".
You can map the buttons to take a variety of actions. Broadly the categories are
Mouse-related actions - right click, left-click, double click
System navigation - scroll left, scroll right, zoom in/out, pan, switch applications
System tasks - run application, open a file
Keyboard - Press a key, hold down a modifier key
Tablet drivers also let you configure how these buttons work depending on the app you are using.
For example you can set a button to
Increase brush size when you are using Photoshop
Increase opacity when you are using Clip Studio Paint
Increase the volume of your speakers under all other conditions
Undo | Redo
Zoom In | Out | to 100% | Zoom to Fit
Increase | Decrease brush size
Increase | Decrease burhs opacity
Rotate Left | Right | Reset to 0 degrees
Switch between tools (brush, eyedropper, etc.)
Select All | None | Invert | Lasso selection | color similarity selection
Go to layer above | below
Display toggle
Precision mode
Pan/Scroll
These are great for "paired" tasks
Zoom In / Out
Increase / Decrease brush size
Increase / Decrease brush opacity
Rotate canvas
Some rotary dials support turning as well as a third press action. This is useful for a situations where there are three related actions such as rotate right, ritate left, and reset rotation.
Wacom Intuos Pro PTH-660
Unlike a pen and paper system, where there is essentially an instantaneous feeling to drawing, a drawing tablet being a digital system where many components are processing and communicating data is always subject to some form of lag.
In the context of drawing tablets, I use the word log to describe how things are "following" the physical pen.
There are two kinds of lag
The details on lag are described in this video series:
Drawing tablet lag - Episode 1: Basics (https://youtu.be/CRwzPJPA_5A) Apr 28, 2023
Drawing tablet lag - Episode 2: Pointer lag (https://youtu.be/tNj6vxx0FWM) Aug 7, 2023
Drawing tablet lag - Episode 3: Position smoothing in the tablet firmware and tablet driver (https://youtu.be/sWvluY9w-Bk) Aug 7, 2023
