Bottom layer not solid

Hi,

I just completed the build of a Mendel90. It works well and I am surprised with the good results without any real tweaking.
But as I am new to this there is a few things I need to ask.

Looking at the attached picture of a bottom layer one could see places where it is not solid. What settings should I look at to correct this?
Using Slic3r and Pronterface printing from SD-card.

Cheers
Dwarf

Use rectilinear infill for bottom layer, check your E steps and check is filament skipping.

I am using rectilinar infill for bottom layer.
The E-steps are calibrated and double checked.

How to I check if filament feed is skipping? I can not see it and everyting else in the print looks nice.

What are your retraction settings? It looks like you are having an issue where the area to fill is narrow and your angles are oblique. I notice that on my prints, there is retraction done in these situations, but they are short moves - so it needs to be ready to print again quickly. Perhaps you are either 1) retracting too far, or 2) you have too small of a minimum distance for retraction.

Just a guess.

My settings for retraction is in the attached image.
Maybe "Minimum travel after retraction" is what needs to be adjusted?

Please keep the input comming, it is helpful!