[Reventlov]

So, I understand the appeal of having something use pens to plot such things but… If I were to just use a regular printer to print those things (art, drawings, …), would the result be really different ? I have no pen plotter nor printer, so… I don't really understand what would be the main differences…

[chantepierre]

A printer will usually leave a dot pattern to reproduce shapes, with a resolution fine enough that everything will be sharply defined.

The blackness of a laser printer is a bit less qualitative than ink, because it's shinier from a large variety of viewing angles.

Here if you zoom it a bit, you can see a very slight wobble in the pen tracks because it catches a bit of the paper's grain, and depositing ink, the paper "drinks" the ink which fattens the lines a tiny bit.

This is more noticeable on the drawings with a lot of pen lifts/drops, where both the lift and the drop leave a dot a bit larger than the line between them.

The one with gradients made with lines closer and closer is especially eye-catching to me because all of those imperfections adding to produce this "worn-out" look in the darkest parts of the gradients.

Some paths overlap a bit and if you look very closely there are more than one nuance of black because of this - in some other places, the lift/drop are close enough that a bit of ink seems to travel by capillarity between the lift and the drop, resulting in two touching lines that were separated in the program..

The ones having a lot of circles show other imperfections, with a bit of ovalization in the circles, and the paths generated to fill the circles with black missing a few parts..

What I like a lot is that the result shows all of those little details that accumulate and produce this imperfect look, without needing to simulate it in Photoshop or another software if you were to print it with a regular printer.

[ghusbands]

> Here if you zoom it a bit, you can see a very slight wobble in the pen tracks because it catches a bit of the paper's grain, and depositing ink, the paper "drinks" the ink which fattens the lines a tiny bit.

I think you're misattributing things. Plotters use stepper motors and so have a minimum distance they can move along each axis. Due to this, they don't produce perfect lines at an angle and do introduce similar artifacts to what you'd see on a screen.

[mkl]

IME older plotters use DC motors and optical encoders rather than steppers, and do seem to produce perfect lines at angles. They can't do curves perfectly, as even when you specify an arc or bezier curve, the plotter breaks it down into small straight segments.

[sleepybrett]

the step resolution is such (80 steps/mm) on the axidraw v3 that this isn't really an issue. From their product page:

* Native XY resolution: 2032 steps per inch (80 steps per mm).

* Reproducibility (XY): Typically better than 0.005 inches (0.1 mm) at low speeds.

[chantepierre]

You must be right, there also must be mechanical steps or wobble at play here. I was hesitant because my 3D printer (lower-end than an Axidraw) seems capable of smoother angled/curved lines than what we can see here. On the other hand plotters I've seen (a long time ago) seemed to not eliminate all vibration in the pen.. but I did not see a mid to high end recent plotter running.

[alpaca128]

FDM 3D printers squish molten plastic onto the previous layer, and that probably helps balance out the limited "resolution" of stepper motors. Also I'm guessing the inertia makes the extruder movement a bit more continuous, after all it's enough to cause artifacts like ghosting when printing at higher speeds.

[globular-toast]

That's disappointing. I had assumed these devices were analogue and able to draw true curves. This makes me not so excited about them.

[Infernal]

No true draftsman

[phkahler]

An analog one could be built with 3 phase motors, but that's another project.

[regularfry]

It's also not that uncommon for people to build intentionally bad plotters (I've done it), because the results when you stick a picture through the process have their own charm.

[sleepybrett]

Similar to a 'prepared piano'. By making your instrument unique you introduce interesting variation and improvisation.

[mkl]

Plotters can make big art [0] cheaper than large-format printers, can be higher precision [1], and produce much purer colours (except pure C, M, Y, or K on a printer, but most colours are not those). The results also look qualitatively different up close, and are to me somehow more appealing.

Printers are more versatile within their limitations, so for many types of art they are better, but for what plotters are good at, to me they are clearly better.

[0] Or woodworking templates, blueprints, or whatever.

[1] E.g. a straight line is produced by continuous movement between the two points, with no pixelation or quantisation.

[nkozyra]

On point 1, there is also a cost to doing registration on large scale stuff. I have the XL Axidraw and am limited to 11" x 17" so if I want to go bigger I have to set up registration marks and make sure they're aligned.

[mkl]

Only for that style of machine, I think (not entirely sure what you mean). Flatbed or large format (paper drapes down each side and gets moved back and forth) plotters don't have that requirement. My A2 flatbed holds the paper in place electrostatically, and nothing can move once that's switched on; you position it where you want and press a button, then smooth it down. The Axidraw style plotters seem quite limited in comparison (and the cheap ones very imprecise).

[nkozyra]

I'm not visualizing what you have but having the bed static certainly makes sense. But any plotter where the tool moves and not the source will have this issue.

[mkl]

If the plotter is big enough to hold the whole piece of paper (or move the paper through on its own) there is no registration to worry about, and flatbed and large-format plotters do that.

Flatbed ones are like this: https://www.flickr.com/photos/anachrocomputer/5183771083, https://www.raspberrypi.com/news/control-vintage-roland-pen-...

Large format ones are mostly used for vinyl cutting nowadays, but they look like something like this: https://www.signmaster.co.uk/hardware_item/graphtec-ce7000-s...

[nkozyra]

Right, that's (the vinyl cutter variety) not wildly different than the Cricut (which I mentioned before, and can also pen plot)

I guess I'm thinking larger than 17" and the two flatbed ones you linked would suffer from the same problem (except that the first probably has no way to do larger than its bed)

[petercooper]

One upside to a plotter is you can work with different media, both in terms of materials (e.g. chalk or paint) but also what you are plotting on to. For example, you can put certain types of marker in and draw directly on to glass or ceramic tile which might have some interest in terms of making gifts.

[matthew-wegner]

It's a fair question! I've thought about that a lot, as someone who has plotted maybe ~200 pieces of their own work (and generated plots for ~500-ish).

In person, it is very obvious that you're looking at something created by a physical pen. The lines have a glossiness to them, a slight pressure, etc. It's an artifact a printer couldn't have created.

Process-wise, it's a fun challenge too, but that's a different thing altogether.

[great_psy]

Serious question, Can this pen effect be simulated, and still be printed with a regular printer ? Would there be a difference then ?

[sleepybrett]

Only if your printer also slightly embosses (they don't anymore really .. dot-matrix and daisy wheel certainly can but then you get resolution problems), can take any ink you can run through a pen (they can't.. or at least they don't.. maybe old ribbon based printers could...). There is a quality to a pen plot that is not reproduced with current 'printer' technologies.

[fmajid]

I have an AxiDraw Mini that I use with a sharpie to label thinks like zippered storage bags, because I am OCD that way. The only reason I'd use a plotter over a printer is if printing on heavy card stock that won't feed through a printer, or if using something like a metallic ink pen for effects you simply can't get with a CMYK ink set.

[j0hnyl]

Plotters are fun, it's like a creative collaboration with a robot and you can hand it any pen you want.

[harhargange]

Concept of Pen plotters is more useful in 2D manufacturing and things like laser cutters.