Solved: Last segment of Photoshop brush stroke does not vary in width

posted in: Problems solved | 3

Problem

I experienced a major problem when I was drawing in Photoshop CS4 with my trusty old Wacom graphics tablet for the last couple of years: When I lifted the pen at the end of a stroke Photoshop would draw the last segment of the line with equal width. This resulted in pretty ugly lines from time to time.

Photoshop Shoelace Bug Intro

I always thought that my old Wacom Graphire 4 tablet (or the pen) was the cause because I was sure I didn’t have this problem in the first two or three years that I owned it. Only when I bought a new tablet (the Yiynova MSP19U+) and produced the problematic line endings with this device, I came to the conclusion that this could be a Photoshop CS4 problem and that it probably was always there but I didn’t notice it in the first years with my Wacom tablet.

Looking for help

I tried to google my problem and after a few attempts to describe it, I finally stumbled upon some posts that helped me. I learned that this problem isn’t unknown and referred to as “shoelace bug” by its victims – although I am not sure if it can be called a bug to be honest.

This thread at conceptart.org made me aware that it is called “shoelace bug”. According to this post on deviantart.com it is a problem with the Windows driver but this thread in Wacom’s forum showed that this problem also exists on MacOS. Some settings and driver related solutions were proposed but they didn’t help me.

Photoshop "Shoelace Bug"

Cause

Photoshop is not applying the actual pressure of the pen every time it draws the brush’s tip (that would be a couple of hundred times per stroke). Instead it samples the pressure and position a couple of times during each stroke. I don’t know the details so let’s just assume this happens five times per second. Photoshop will then interpolate the line thickness between the sample points.

This is actually pretty smart as this prevents jittery lines and line thickness – most, if not all, drawing tools do this. The problem is that Photoshop doesn’t use the sample with zero pressure that the pen will send when it leaves the screen and instead uses the last pressure sample again, resulting in a segment without variation in line thickness.

This also means that this problem will be more obvious if you draw fast lines – something I tend to do.

Solution

The aforementioned post on deviantart.com made me aware of a tool called Lazy Nezumi. It works as a Photoshop plugin and is able to apply a different smoothing algorithm to the brush strokes.

Let’s have a look at some comparison pictures.

Lazy Nezumi has lots of other cool features. It looks and feels very professional. I am using it for two days now and didn’t have any issues with it.

It’s free for 30 days and costs 30 Dollars afterwards – being a software developer myself this seems like a fair price to me (I am still using the trial version as I’m writing this, though).

Another solution would be to stop using Photoshop and start using software that was actually made with digital drawing in mind (Manga Studio, Sketchbook Pro, Painter). But that may cost more than Lazy Nezumi and requires to learn a new tool (which, if you’re working as an illustrator, will take away time you could spend on contract work).

Is this a bug?

From what I could gather during my research, other graphics artists are angry at either Wacom or Adobe or both because this “bug” lives/lived in the code of Photoshop for many versions. I would like to add my opinion that the behavior of Photoshop could be intentional.

I use Photoshop to draw my comics – but Photoshop isn’t a “drawing tool”. It’s an image editing software. It has drawing capabilities but they are aimed towards image editing as far as I can tell. The Photoshop team probably has the opinion that the brush tool is more useful for this when the line does not end with zero pressure. I also use Photoshop to retouch my photos and usually disable pressure sensitivity when I do this as pointy line endings may produce ugly results when I clean up skin or draw masks. I don’t know about newer versions of Photoshop but from what I could gather at least the CS2 to CS5 versions have this “bug”. Newer versions may have been “fixed”. But I’m still stuck with CS4 and don’t plan to upgrade anytime soon, so I had to find a solution. Maybe you’re like me and will find this useful.