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  • Writer's picturePierre Paslier

Interview with Dan Catt

GH: We're so curious to find out: who are you, where are you from, and what do you do?

Dan: Hi, I'm Dan Catt, 48 (just to put some of the later stuff in context), and based in a sleepy medieval town called Shrewsbury in the UK. At the moment I split my time between working with a studio in New York, helping museums manage their collections, and setting up a small art studio for myself to spend a little more time trying to be a "proper" artist.

"There's a sort of electric energy that runs along the edges, not in the black or in the white, but the juxtaposition between the two."

GH: What is the underlying philosophy behind your work?

Dan: All the way through art college and my art degree, there was one thing that caused me trouble, the simple fact that I couldn't draw or paint to save my life. For some reason, at the time, being-able-to-draw was considered an essential part of an art course. I cunningly hid this fact by turning to computers, slow elementary computers. Two things influenced me at the time (time being around 1984-1994).

Kiss, 1961 - Bridget Riley

The first was the work of Bridget Riley and the black & white op-art movement. In particular her 1961 artwork "Kiss". The wonderful part about that work is that even with just black and white, those two binary colours, something lovely happens. The curve of the black comes down from the top and nearly, nearly, but not quite touches the straight black from below, and it's at that point the magic happens. There's a sort of electric energy that runs along the edges, not in the black or in the white, but the juxtaposition between the two.

Binary, the zeros and ones are far more hidden now, tucked away behind hexadecimal and millions of colours, they're still there but deeper inside. At the time I was using 8-bit computers, and the 0s and 1s were much more prominent, bigger and chunkier. They were all you pretty much had to work with. But Bridget Riley taught me that it's the point where they meet that's important, how they push up against each other, the edges and the interactions. Bridget worked with Black & White for six years before dipping into colour in 1967. There's a temptation to move forwards too quickly, while there's still magic to be discovered just exploring deeper and more deliberately within your current constraints. The second, later, was the work William Latham, who worked with evolutionary art, a precursor in a way to genetical algorithms and neural networks. The principle being that the computer, with no artistic or aesthetic judgement of its own, would "grow" shapes and forms, while the artist would take on the role of a "gardener" pruning and cross-breeding for artistic fitness. The two would work together, the computer acting as the art studio assistant, the artist guiding the output, resulting in a piece that neither artist or machine had initially conceived of. The final artwork arrived at through a collaborative process. Which is a long way of saying that throughout my degree, I disguised the fact that I couldn't draw by programming the computer to spent all night (and sometimes the weekend) making art. So that I could come down in the morning, pick the best ones, and then tell it to make more like that, please. That's the philosophy I still have now, working in collaboration with computers and machines, letting them do all the hard work, while I get the fame and fortune from Instagram.

GH: Can you pick an artwork and describe your workflow?

Dan: Sure, I think I'm going to go with this one called "Ghost".

This, like most good things, came out of an accident. I'd been working with some code that made flowing landscapes. It would draw horizontal lines and then perturb them based on Perlin noise; basically, it made lots of gentle waves. The code is straightforward, but the effect rather pleasing.

I wondered what it would be like if I used concentric circles instead of lines. Rather than having waves flowing downwards, they'd form a pool of waves instead.

Because I write my own code, and I like an easy life, whenever there's a value used in the system that can change, I add it to a GUI widget that allows you to change that value with a slider.

Which gave me access to the starting and ending position and I realised that instead of circles getting smaller towards the middle, I could keep them the same size and just make them move down.

So that's what we have with "Ghost", a simple perfect circle starting at the top, slowly getting gently deformed with Perlin noise as it moves down the page. Leading to quite a delicate textile result, which wasn't what I was aiming for at all.

If you follow the following link on a laptop or desktop machine (it won't work on mobile), you can see the settings I used-ish (and plot your own if you feel like): make your own ghost

What I particularly like about the code is the amount of design space you can move around in, which I've abused the hell out of. By sliding the mid-point over to the side, I've gotten results that look like a moon. By rotating that effect and saving out SVGs at 0, 120 and 240 degrees, then overprinting in different colours, you end up with cool-looking blobby things. Reducing the number of segments down to three and you get pyramids, and so on.

GH: What's been inspiring you lately?

Dan: Funnily enough alchemy and sigils. From a purely aesthetic angle!

I like the idea that alchemists tried to come up with a set of symbols that described certain elements and effects and documented ways of trying to combine them. There's a whole language in there that's similar to computer programming. We put together symbols in orders that act as a set of instructions to create an output, and alchemy, if you squint at it and look at it from a certain angle could, if you try hard to force it (which I am) be said to be the same thing.

Sigils are similar, different "secret" shapes, lines and marks having special powers that combined in ways to create spells, make wards and summon creatures. Various old organisations used variations on this to create codes, allowing them to send messages back and forth, some of which look rather pretty.

In the above example of the Rosicrucian cipher, from the book "Sigils, Ciphers and Scripts" (highly recommended), you can see the logical steps taken to get from the name "Micheal" to the final design, which has code and pen plotting written all over it.

I think it'd be fun to have the pen plotter endlessly creating mystical incantations and circles, attempting in its way to cast spells and bring forth magic.

Of course, now that I'm actually thinking this out loud I'm more worried it's the start of a bad 1980s horror film, so if I stop posting on Instagram for a long while you know what's happened.

GH: Tell us about your setup. Where do you create? What tools do you use? Dan: I'll do this in the order of software, hardware and pens.

I used javascript to write all my code that then spits out SVG files. It's a mess of code that is about 80% of the way to being a usable library and 20% spaghetti and nuances that only I understand. What I like about JavaScript is that it makes it very easy to put the tools online.

Pretty much all of my plots on Instagram are generated with the code sitting over here:

I keep promising myself that'll I'll write a blog post and post example results for each one, but it turns out it's more fun making plots than writing about them.

I send things to the plotter using the axidraw command-line interface, as I find it more straightforward. Sometimes I used a tool called SVGSORT to optimise the plot.

Two questions I get asked surprisingly frequently is "What pens do you use to draw on black?" (answered below) and "How do I get started writing code to make things like yours?"

Every last thing I do pretty much used the below eight concepts combined in different ways. If you're looking to get into pen plotting art your homework is to look into the things listed below; they will take you a long way, no matter which language you use.

  1. moveto(x, y)

  2. lineto(x, y)

  3. Loops

  4. The sin() function

  5. Perlin noise

  6. Polar coordinates

  7. Rotation around the point (0, 0)

  8. Translation of shapes in the x, y plane.

Those are the raw ingredients of each of my plots, just mixed up in different ways and different proportions.

On the hardware front, well, everything used to be set up beautifully in my own little art studio in town, but in the Coronavirus lockdown, I had to grab a bunch of stuff and cram it into a spare room at home. This is my current setup if you'll please excuse the mess.

That's an Evil Mad Scientist AxiDraw V3/A3, it is a thing of wonder. If you buy one I highly recommend buying a few spare servos at the same time and chucking them in a draw, the thing is robust as hell, but the pen lifting servo should be considered a consumable like printer ink.

Controlling it is an old MacMini with a tiny monitor which I used to power an old art piece. I can also recommend the Lenovo ThinkPad Keyboard; the little "nipple" thing saves you a mouse.

Because I've been asked before, that's a Manfrotto tripod that lets you remove the centre stem and mount it horizontally, so I can take time-lapses from above. The camera is a FujiFilm X100F, which has a timelapse mode built-in.

Pens and Paper:

I highly suggest getting the blackest paper you can get your hands on when doing black plots, I use Fabriano Black Black 300gsm. Plotting onto black paper is utterly horrid, especially when using white ink, it tends to skip and fade so much.

I sidestep that by using silver ink instead, with the Uni-ball Signo UM120-NM.

Because I don't use Inkscape to set up my plots, I used the command-line tool, I don't know how this translates, but I always run my silver/white plots on black very slowly, around 10 to 15 speed. I find that helps the ink go down onto the paper evenly and reduces skipping.

Because light ink gets absorbed into the paper, I tell it to run each plot twice.

For coloured plots, I used (and have seen recommended) the Staedtler triplus fineliners, which are really good and last a long time.

A lot of the time, though, because I hate the idea of throwing all that plastic away, I use TWSBI eco fountain pens.

The ink lasts forever; it's easy to buy and make up pretty much any colour, and only takes seconds to change the ink from one colour to another. The axidraw lets you set the pen at a 45-degree angle, which is perfect.

Finally for the truly daring, my secret recipe for white fountain pen ink:

  1. Get a sacrificial TWSBI fountain pen.

  2. Mix two-thirds Dr. Ph. Martin's Bleedproof White (stirred), with one-third Noodler's Blue Ghost UV ink.  

  3. Fill fountain pen, and use.

  4. Immediately rinse out and wash the pen; it may even survive.

Dan Catt, Shrewsbury, UK

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