Discover more from The Dan Catt Pen Plotting Newsletter
📙 #002 - The plotter family grows
The case of the wonky lines
When I first got "Trevor", the pen plotter, I ran a test plot of 400 parallel lines crammed onto a sheet of A3 paper. Which revealed that Trevor had a kink, and that kink ran down the whole A3 page at a couple of inches in from the margin.
It's worth noting at this point that I am terrible at DIY; I can't do anything which involves putting things together at all. That was one of the main reasons for getting a more expensive AxiDraw plotter over some of the cheaper build-it-yourself models, I wanted it to just work.
One option was to send the whole plotter back, and another was to go back-and-forth with some troubleshooting.
I went with the third option, a bent paperclip and some sticky tape. This did the job well enough. If I avoided certain designs, it wasn't really a problem. However, one area of art I do particularly enjoy is just that, building up textures with many precise lines, a whole area now shut off. Instead, I stuck to curves and various tricks to work around the problem.
Sometimes the paperclip would come loose, and whatever I was plotting would be wonkier than usual, at which point I'd grab some new tape and fasten things up again.
This brings us to the other day.
About a month ago, I decided to sell some digital art as an experiment, and in a very "me" way, I'll write more about that whole thing soon. But the short version is that I created some animations out of 240 frames of SVG files. If someone bought one of my digital art pieces, they would also get a pen plot made from one of their choice frames or mine if they didn't specify. Seemed fun.
Until I sold one, well seven, but only one concerns us for the moment.
For various dull reasons, part of the _new_ process of making one of these plots involves Adobe Illustrator, mainly for placing the design into the middle of an A3 sheet, something my code does typically, but not in this instance.
I placed the design, exported it, and sent it to the plotter.
It was wonky. The lines weren't evenly spaced, and there was the odd kink here or there. Things I'd definitely seen before with Trevor. So I picked a different frame, one that I thought may hide the kinks a little better.
Same thing; odd spacing, wobbles and kinks. This was getting pretty frustrating now.
I dug out some instructions on fixing the issue; a PDF buried deep on the AxiDraw website. I even had to use a spanner!
One test plot of straight lines later, everything seemed to be working much better. I'd fixed it! All this time and I could have sorted it out with five minutes of work; I am, of course, an idiot.
Elated, I sent the design to Trevor again, only for it to once more come out all wonky, which didn't make any sense. The test plot was good, but this one was bad, again.
At this point, I was super frustrated; I _needed_ this plot to work. I checked a few websites and found one (pimoroni.co.uk) that had a single AxiDraw in stock (everywhere else was sold out), and it'd arrive the very next day. I hit that buy button so fast.
A short while later, I looked at the wonky plots again. The pre and post-fixed plot versions were the same — the same mistakes in the same places.
That's when I checked the actual files I was sending to the plotter. There it was in the file itself, all the kinks and wobbles.
And that was the day I learnt that Adobe Illustrator exports SVG files with a default of two decimal places, which was doing all sorts of rounding up and down, creating the wonky plot. I changed the export settings, and everything was perfect.
By which point the new AxiDraw was dispatched and on its way.
I can't say I'm upset to have a second plotter; it just happened sooner than I expected.
As an aside, the first plotter, "Trevor", which I bought on 27th Sept 2019, has the serial number A3-0361.
This second one has the number A3-1096.
Some wild assumptions suggest 735 V3/A3 AxiDraw pen plotters have been sold in the 561 days, about three every two days. That doesn't include the "Special Edition" SE/A3, standard A3 or V3 XLX (extra long) versions, but I think it's an interesting data point.
Not every AxiDraw will be used for art, but it seems not unreasonable to suggest that along with non-AxiDraw machines, we have one new pen plotting artist a day.
Still pretty niche but growing all the time.
News from the world of Catt
Copperplate etchings and prints.
For the past few weeks, I've on and off been playing with using the pen plotter to engrave metal plates. I started with aluminium "practice" plates and then moved onto full-on proper copperplates.
I even dared to ink up a plate late one day and ran it through a small press as a test. I didn't do any of the things you're supposed to do; clean the plate properly, ink it correctly, wipe it properly, dampen the paper and the thing I regret the most, wearing gloves.
Despite all that, the first print came out reasonably well. Now I just need to clear some time to do it properly.
* * *
Another fun thing that I _finally_ got around to was tweaking some of my code to send _half_ a design to the pen plotter.
Part of the pen plotting process is speeding up the time it takes to draw by optimising the order in which the lines are drawn. This causes the lines to be drawn in what looks like a strangely meandering fashion and one that I really like.
Sometimes the halfway drawn design looks as good as the final thing.
Sadly it's not as simple as just stopping the machine because another part of the process is to draw the whole thing backwards. Running a plot in both directions improves the coverage when using metallic pens on dark paper.
So the update to the code was to take all the lines, optimise them, throw the second half away, and write out the remaining ones in both directions.
I've only just started exploring what the results look like, but I'm looking forwards to trying some more soon.
Links and resources
No links and resources this week.
There was a quote I wanted to include, which I swear was related to Tyler Hobbs' Ectogenesis images (https://tylerxhobbs.com/ectogenesis), but I can't find it now.
It went roughly: "I don't like it when people call my generative artwork random because it's not. If I put the same numbers in at the start, I will always get the same image out at the end".
Sadly because I can't track it down, I can't be sure I didn't just imagine it. Although it's always a good idea to read Tyler's essays anyway: https://tylerxhobbs.com/essays
Around the Internet
This is a small selection of things that have caught my eye from the internet over the last couple of weeks.
These lovely cards from Andy Wallace, because I like the precision they have been taped down with.
These beautiful forms that Amy is working on.
This pen plot by Jan Hopkins, which comes at pen plotting from a totally different direction to most; I love the linked lace designs.
And this music from Hannah Peel has been keeping me going.
I did it; I managed to hit my target of Tuesday, once every two weeks.
This is especially surprising considering how utterly busy the last couple of weeks have been, something I need to go into more details about in the following newsletter.
I had some lovely feedback from the last issue; thank you, everyone, for that. I'm still getting into my stride, and I think I will have gotten the hang of it when I get to issue 52 or so, only a couple of years to go!
Please send more email to email@example.com.
Elsewhere on the Internet
Yup, I still haven't gotten around to sorting out this section. The "Call to Action" part of the newsletter, where I send everyone off to some corner where exciting things are happening.
Perhaps soon, that'll be YouTube, but for the moment, just having you here in the newsletter is fantastic.