If your 3mm pen width is correct*, you'll need to change to a very large grid size setting. Then you'll have to scale up the image so it's recognizable at the huge grid size. The largest pen width I've used is ~1mm, which was a standard sharpie. The grid size was probably around 100.

The issue is your pen width isn't much smaller than your grid size, so there's very little opportunity for different values to be drawn in a pixel. A few lines from your pen will make a black pixel with your pen/grid combination.

While testing, you might want to select a small area of your photo that has range of values. That will save you time and ink. And watching dark background pixels draw is boring. ; )

*Have you tried the "test pen widths" feature? The button is under the "SETUP" tab. It will print a series of pixels to help you decide the correct value for pen width.

"Grid size" sets the size of the pixels that make up the polargraph drawing (it used to be called "row size", because it's the width of a row of pixels).

"Sample area" influences how sharp or blurry your drawing will appear. A sample area of "1" is sharpest (you'll rarely want this value, however, unless you're purposely making "pixelly" art). I believe at "1" the controller checks only one pixel of the source bitmap to determine the value for the polargraph drawing's (much larger) pixel. Larger "sample areas" will sample more pixels and average the values, resulting in a softer image. For a standard image I don't stray too far from the "grid size" number when choosing a sample area (though I'm interested in hearing what other people do). If you're doing a baby portrait, you'll want to bump up the samples to make it softer looking. A vampire pick will look more menacingly pointy with a lower value.

To test pen widths, choose a PEN TEST START TIP that is a little smaller than you think your pen is, and a PEN TEST END TIP that is larger than you think you need. PEN TEST INCREMENT SIZE will set how many examples pixels are drawn getting from the "START TIP" to the "END TIP", increasing the pen width used for each pixel by the value you choose. It will draw black pixels at a number of pen widths and a guide along the top to help you see where the pixel boundaries are. The correct pen width is the pixel that is most efficiently filled, a black pixel that doesn't waste ink (and time) by having more lines than are needed.

Success !

First decent print, this time I used an image of Don Draper (Mad Men), Grid Size=20, Sample area = 15, 0.4 mm pen size and a smaller size dry erase marker.

Now to figure out why it's trapezoidal 🙂