Pressure Sensitivity not working

Which version of Inkscape did you install?

Note: the official download links to Inkscape 0.48.2 which has known issues with tablets and pressure sensitivity:
Bug #845354 "Critical Wacom tablet glitches (0.48.2)"
<https://bugs.launchpad.net/inkscape/+bug/845354>

Please download and test the latest bug-fix release 0.48.3.1 (soon to be announced on Inkscape.org) - this latest installer for Windows is built with the newer version of GTK+ toolkit which has several tablet issues on Windows fixed):

http://sourceforge.net/projects/inkscape/files/inkscape/0.48.3.1/

With regard to the remaining questions: not all of the tools support pressure sensitivity (it wouldn't make sense for a rectangle tool for example).

Pressure sensitivity is supported for example with the Calligraphy tool:
<http://tavmjong.free.fr/INKSCAPE/MANUAL/html/Paths-Creating.html#Paths-Calligraphy>

Note: you might have to configure the tablet in 'Files > Input Devices > Configuration' (make sure to have at least the pen of the tablet enabled (set to 'Screen'), and save the changed configuration if needed. In case you had earlier deactivated pressure sensitivity, re-enable it again in that dialog, save the configuration and restart Inkscape.

> I'd also like the ability to use sensitivity along with the pencil tool

The pencil tool does not have features which have pressure sensitivity support.

> He opened up a dialog menu in-program and altered aspects of the brush and line settings.

Probably he used the pen/pencil tool with a 'Shape' from the dropdown menu on the controls bar: this applies a 'pattern-along-path' path effect as 'vector brush'. Those settings can be edited via 'Path > Path Effect Editor', and the original pattern source can be edited on-canvas.

For more information, please read the corresponding sections in the manual:
<http://tavmjong.free.fr/INKSCAPE/MANUAL/html/Paths-Creating.html#Paths-Bezier>
(Scroll down to "Shape: Applies a shape to the path after it is drawn")
as well as
<http://tavmjong.free.fr/INKSCAPE/MANUAL/html/Paths-LivePathEffects.html>
<http://tavmjong.free.fr/INKSCAPE/MANUAL/html/Paths-LivePathEffects-PatternAlongPath.html>

Thanks very much for your swift replies.

I'm using version 0.48 of some description, but cannot see which version it is - why isn't it in the 'About' screen?
Therefore, I cannot tell if it's 0.48.2 or 0.48.3

I've checked the tool settings - pressure sensitivity is turned on and the Wacom tablet is recognised and in the list of items to test. However, the status is set to 'Disabled' rather than 'Screen'. I can't seem to change this and cannot find the preferences.xml file. Please help? It does seem that if I can change these options to 'Screen' I can test and probably fix the problem.

> With regard to the remaining questions: not all of the tools support pressure sensitivity (it wouldn't make sense for a
> rectangle tool for example).
> Pressure sensitivity is supported for example with the Calligraphy tool

Which tools do you state have pressure sensitivity support? Only the calligraphy tool?

As I previously stated, I used the laptop of a friend yesterday, with the Pencil tool (I am very sure about this), and drew on it myself. It was pressure-sensitive. By this I mean that the line grew larger as I pressed harder and conversely shrank as I pressed more softly. If he'd used a pattern-along-path in the tool he passed to me, I imagine it would have remained identical in orientation regardless of path. Ideas?

Previously the boxes to the left of the WACOM tools would not respond when I clicked them, leaving me unable to turn those items on.

Now, I've managed to set them to 'Screen'.

However, when I attempt to draw, or even click the canvas with the pen, the entire canvas is covered in radial lines. In Calligraphy mode with default brush setting.

> Therefore, I cannot tell if it's 0.48.2 or 0.48.3

Please open Inkscape menu 'Help > About Inkscape' and look at the information displayed in the upper right corner. If you have Inkscape 0.48.2 installed, upgrade to 0.48.3.1 (pressure sensitivity on Windows with 0.48.2 is known to be broken).

> However, the status is set to 'Disabled' rather than 'Screen'.
> I can't seem to change this

Did you try to click on 'Disabled' and choose 'Enabled' from the dropdown list?

> Did you try to click on 'Disabled' and choose 'Enabled' from the dropdown list?

Sorry, typo: I meant to say "(…) and choose 'Screen' from the dropdown list"

> As I previously stated, I used the laptop of a friend yesterday,
> with the Pencil tool (I am very sure about this), and drew on it
> myself. It was pressure-sensitive. By this I mean that the line
> grew larger as I pressed harder and conversely shrank as I
> pressed more softly

This is not possible with the pencil (freehand) tool (neither in any released version of Inkscape nor in a current development snapshot build) - varying the stroke width like this works with the calligraphy tool.

> Did you try to click on 'Disabled' and choose 'Enabled' from the dropdown list?

I did - I already explained this in an earlier message - see my additional messages just before your reply.
It wouldn't react or respond and the checkbox was frozen out.
I have now managed to click 'Screen' but other issues have arisen.

"Previously the boxes to the left of the WACOM tools would not respond when I clicked them, leaving me unable to turn those items on.

Now, I've managed to set them to 'Screen'.

However, when I attempt to draw, or even click the canvas with the pen, the entire canvas is covered in radial lines. In Calligraphy mode with default brush setting."

> This is not possible with the pencil (freehand) tool (neither in any released version of Inkscape nor in a current development snapshot build) - varying the stroke width like this works with the calligraphy tool.

Weird. I watched him do it and replicated it. Perhaps it was a 'very' complicated stroke. Hm.

> However, when I attempt to draw, or even click the
> canvas with the pen, the entire canvas is covered in
> radial lines. In Calligraphy mode with default brush setting."

Please see my earlier comment: check the version you have installed via Inkscape menu 'Help > About Inkscape' and upgrade to Inkscape 0.48.3.1 if you have 0.48.2 installed (pressure sensitivity on Windows with 0.48.2 is known to be broken, see linked bug report <https://bugs.launchpad.net/bugs/845354> and its duplicates, among others).