Extrusion Width absolute vs. percentage

In the manuals section about extrution width says (http://manual.slic3r.org/expert-mode/extrusion-width)

It is important to remember that if the extrusion width is expressed as a percentage then this is computed from the Layer height property, and not the Default extrusion width setting.

So;
If I enter layer width 200% I get a width corresponding to double layer height specified in "Layers and Perimiters"
If I enter layer width 2 I get a width corresponding to double layer height specified in "Extrusion with's -> Default extrusion widht"

The thing is I have the imported settings from the Ormerod2 githubfiles which gives me the value 0.8 for the field First Layer, all the others are 0 (auto)

That gives me less extrusion of material for the first layer, still I get good adhesion to the bed. On the other hand I have increased the extrusion multiplier to 1.05 to get adhesion in the first place. I am starting to question this default (0.8) value when trying to get rid of some artifacts in higher layers in the prints.

I am asking this to get the theory right before starting trial and error.

"If I enter layer width 200% I get a width corresponding to double layer height specified in "Layers and Perimiters"" = Correct

"If I enter layer width 2 I get a width corresponding to double layer height specified in "Extrusion with's -> Default extrusion widht"" = Wrong
You would get an extrusion width of 2mm , which is not possible of course unless you have a wide nozzle. set the absolute layerwidth (0.4 or other here)

Be carefull to distinct between "Layer height" and "Layer Width) (Extrusion width) and with Slic3r you have the possiblity to set both for First layer" and Layers generally.

To avoid confusion you could set absolute values (0.4) instead of relative (200%) but be realistic of what is possible with your nozzle.

Edited 1 time(s). Last edit at 11/24/2014 10:35AM by justcurious.

Ah, so without the percentage sign the value is absolute width in millimeters. Correct?

Then 0.8 means 0.8 millimeters not 0.8 (as 80%) of the default extrusion width.

One has to read carefully to keep all the values and terms straight.

That is correct :-)