since i do have my polargraph it is really hard not to spend hours in the stationery. so many pens...so many opportunitys...
I found a mixture of a pen and a brush, FABER-CASTELL PITT artist pen. So i bought three of them, new paper in DIN A2 (594x420), started my polargraph, and 12h later the wire of the servo did mess up and the drawing was garbage. second try, new paper, same pen, same picture. 15h later the pen started to get empty 🙂 OH DEAR!! (edited - sn) so now third try with new pen. the interessting thing is that these pens are refillable. maybe this gives new opportunities...
maybe someone should add a feature showing how many meters the pen did draw and still have to draw 🙂

so maybe after 3 days of waiting i will have a complete drawing ready 😎

cheers
thomas

Hi Dani,
sadly I did not really spend a lot of time in the past months with my polargraph. The tip of the faber castell pens did not flatten out a lot. you have a constant line thickness over the whole picture. a finished Picture with this pen is hanging since half a year on the wall and you can not really see that the color is fading. I did not really tried to refill my pens. the next thing I would like to try is using refillable blackboard pens.

Thomas

Thanks for the update. Keep them coming. 🙂

I've been doing large drawings with Edding 3000 pens. Turns out the colored ones fade in the sun after a few days (outdoors in the sun).

colour fading of stabilos (unfortunately I didn't scan the images after drawing...but the one in storage looks pretty close to the others I just drew with them):

I think my scanner also does "some" funky colour correction...but not much...in general Stabilos fade quickly (whereas black and yellow seem the lightfastest)

you are welcome 😎 (some longterm exposure test of the different pen-brands will also come up...but in a long time from now 😉

BUT I think I found my magic very satisfying solution for now!:
I love the Faber Castell PITT Artist pens! Right out of the box they also last very long and they claim to be very lightfast also. Although Faber Castell sells them as a non-refillable item, they are:
http://rodmckie.blogspot.co.at/2008/07/making-faber-brush-pen-last-longer.html
https://www.youtube.com/watch?v=xKNMZmlM39M

I couldn't get the Daler Rowney Ink Bob is refering to and instead bought the "Aero Color professional" acrylic ink of the German company "Schmincke". That very lightfast ink is initally made for air-brushing but can be used with pens down to a 0.15mm tip! And they offer the ink in the Basic CMY colours!!!! And also in silver, gold, bronze etc...(might be interesting for DaveO ?) They also sell empty pens for loading the ink. But if you get a close enough colour from the Faber Castells they adapt to the new ink quite quickly...and an additional bonus of the Faber Castell brush pen tip is, that you can flip the tip and therefore double the usage time!
http://www.aerocolor.de/produkte.html

One 28ml Pipette bottle is about 6 Euros...and you can barely see the 28 drops I already put in my pens missing from it....

Both say in their explanations that you should only refill them with about 3 drops....that's not my experience. (with 3 drops of the "AERO Colour Ink" you are not even nearing the initial ink load of the pen...) The pad inside can hold way more ink until it is saturated. Although I have to refill them in several rounds as the ink needs to sink down so that the end of the pad can hold more. My current refill is at 4 rounds with 5 drops each and a resting period with the pen upside down for 15 minutes in between) As soon as I know the max capacity I'll let you all know. (But you shouldn't miss the inside of the ink-pad (it is wrapped with some plastic) as the ink will run along the casing and leak at the tip then...)

D

the image that inspired the artwork is from here (based on a photograph from Dr. Oliver Niehuis, ZFMK, Bonn):
http://www.wired.com/2014/11/when-did-insects-evolve

Really thanks for this study 🙂