Elephants in Stilletos

I was intending to post this yesterday but my brief intoduction to Inktober ended up taking a lot longer than planned, so I postponed this one…

Yesterday’s prompt word for Inktober was “Pressure”. As usual, I thought about several possible avenues for interpreting this prompt, one of which was the scientific definition of pressure as force over area. This reminded me of a fun fact I learned while I was at school, namely that a woman in stiletto heels will do more damage to a wooden floor than an elephant, because although she weighs a lot less than the elephant (assuming average-sized women and elephants), all her weight is concentrated over a very small area compared to the elephant’s feet.

While thinking about this yesterday, it occurred to me that this was all based on the assumption (to be fair, probably a fairly safe one) that the elephant isn’t also wearing stiletto heels. This set me off on a rare foray into cartoon-style illustration:

Probably not one of my best sketches ever, but it was quite fun to make. I also took a bit of time to do my own calculations to verify the assertion that a woman in stilettos exerts more force than a barefoot elephant.

To do this, I looked up a few figures and estimated a few others.

According to an article appearing in the Independent in 2017, the average weight for a woman in the UK is 11 stone. That’s slightly higher than I expected, but I decided to go with that figure. Converting to metric units, that’s close enough to 70kg, so we can use that for our woman’s weight.

Except that it’s actually her mass, since weight is a force (gravity) acting on a massive object (i.e. an object that has mass, not necessarily a particularly large one) and is dependent on the strength of the gravitational field it’s in. We actually need the weight for our calculation (as pressure is force/area), but that’s easy enough to calculate from the mass. Newton’s 2nd law says that force is mass times acceleration (F=ma if you like equations, as I do) and in this case the acceleration is that due to gravity. That varies from place to place around the world but it’s roughly 9.81 metres per second squared. For my rough calculations, I decided that a nice round figure of 10m/s2 would do fine. So our average woman weighs about 700 Newtons.

I didn’t make a note of where I found the figures for an elephant but apparently a female African Bush Elephant weighs on average around 3 tons. I’m not sure if that’s supposed to be long tons or short tons, but either way I decided that just calling it 3 metric tonnes (3000kg) would be close enough. Again, that’s actually the elephant’s mass (everyday language tends to be shockingly imprecise when it comes to such things), and her weight would be 30,000N using the same figure of 10m/s2 for the acceleration due to gravity. Incidentally, I decided that since our woman is (by definition) female, I’d go with a female elephant too (they tend to be a bit smaller than the males) and since I tend to think of African savannas before African forests or any part of India when thinking of elephants, I opted for an African Bush Elephant (a species that’s generally somewhat bigger than the the other two varieties).

That bit was relatively easy. Working out the areas was slightly more problematic, especially for the woman in stilettos. You will probably be relieved to hear that I don’t have any stilettos in my own shoe collection, and I was too lazy to go out and find a woman with high heels so I could measure the surface area of her heels and toes together or figure out how much of her weight would be concentrated on each part of her foot. For the initial calculation, at least, I wanted to work on the assumption that both the woman and the elephant would be standing with their weight evenly distributed across all their legs (that sounds a bit weird for the woman – obviously “all” is just “both” in her case!). A bit of online research revealed that stiletto heels usually have a diameter of no more than one centimetre, but I couldn’t find anything out about the area of the front part of the foot that would be in contact with the ground and presumably bear its share of the weight. I settled for a rough estimate of about 1cm2 for the surface area of each heel and 50cm2 for the surface area of the toe/ball of each foot. For convenience I tweaked the latter down to 49cm2, giving a total surface area of 100cm2 for both feet (heels and toes combined).

The elephant’s foot size was actually a bit easier to determine. Apparently a typical African Elephant has feet between 40 and 50cm in diameter. I decided to give the woman a bit of a helping hand by assuming our elephant had relatively small feet (hence providing less area to spread the weight) and therefore a 40cm diameter, or 20cm radius which, if we assume that the feet are circular, gives a surface area of about 1250cm2 per foot or 5000cm2 for all four feet.

To ensure our final units are correctly expressed as Pascals, or Newtons per square metre, it’s handy at this stage to convert those areas into square metres rather than square centimetres. The woman, standing with both feet firmly on the floor is putting all her 700N of weight through 0.01m2 of the floor, while the elephant’s 30,000N is being spread across 0.5m2 with the net result that the woman is exerting 70,000N/m2 or 70kPa of pressure on the floor, while the elephant is exerting only 60,000N/m2 or 60kPa. So our average woman is indeed liable to do a bit more damage to our delicate wooden floor than our average elephant, though the figures are actually quite close.

The difference gets more pronounced if they both put all their weight on a smaller area. I’m not sure how practical it would be to rest all your weight on one heel while wearing stilettos (mind you, I’m not convinced it’s very practical to wear stilettos in the first place) but suppose she’s able to do so, our woman is now channeling 700N through an area of just 1cm2 or 0.0001m2 which makes for 7MPa of pressure (that’s 7 Megapascals, 7 million Pascals or 7×106Pa if you’re not afraid of scientific notation – it’s definitely much more convenient than long trails of zeroes at either end of your numbers). Assuming that it’s enough of a challenge for our elephant to stand on just one foot, without going up on her toes or heels, she would be putting 30kN through 0.125m2, which amounts to 2.4×105Pa, which is 240kPa or 0.24MPa – significantly less than the woman on one heel.

Since my cartoon was based on the idea that an elephant wearing stilettos would do more damage to the floor than a woman in stilettos, I couldn’t leave this set of calculations without considering the pressure exerted by our elephant if she were to don a set of stiletto heels. Presumably these would have to be custom made and I’ve no idea how big they would be, nor whether she’d wear them on all four feet or just two, so let’s assume that the heels themselves culminate in points the same size as the woman’s ones, i.e. 1cm2 each and the elephant has somehow managed to contrive to stand with all her 30kN of weight bearing down on just one of these heels. That would make for a pressure of 3×108Pa, or 300MPa. As we would expect, our elephant in stilettos would do considerably more damage to any floor than our woman. It’s probably just as well that elephants are not, as far as I’m aware, in the habit of wearing stiletto heels.

I should probably add that it’s been a good few years since I last did this sort of calculation, so I hope I haven’t made any major mistakes with my units or figures, or any assumptions that are too crazy (apart from the basic premise itself, perhaps). Still, I’m fairly confident, at least that the claim made by my cartoon is fundamentally correct:

An average-sized woman in stiletto heels exerts more pressure on the floor than an average-sized elephant…

… unless, of course, the elephant is also wearing stilettos!

(Magnus Forrester-Barker, 2021-10-09)

Ink-tastic

Since I last posted, just over a month ago, I’ve been continuing to do more or less regular drawing, with both my iPad and more traditional media. As I’d hoped, my life drawing class restarted about 3 weeks ago and I’ve really enjoyed being back there. I also decided to have another go at Inktober this year.

Inktober is one of those month-long daily challenge things that seem to be all the rage these days. This particular one, as the name suggests, takes place annually in October and is based around doing daily drawing. Officially it’s supposed to be done using ink in a pen or brush (with optional pencil underdrawing), but the real purpose of Inktober according to its creator, Jake Parker, is to encourage creativity and help people to improve their skills and develop positive drawing habits, so other things such as digital art are fair game (it says so in the official Inktober faq, so that’s good enough for me). There is an official prompt list that you can follow or ignore as you see fit, and artists of all skill levels are encouraged to post their results to social media, though that is optional.

I first did Inktober in 2019 and that time I did it with black ink on white paper and mostly (though perhaps not exclusively) using a Pentel brush pen that was recommended by Jake Parker (and, as I recall, a pencil for under-drawing on a few of the days though not all that many). I stuck to the official prompt list for that year, though with loose interpretations of some of the prompts (my favourite one being “legend”, which I chose to read as “leg-end” and therefore I drew a self-portrait of my foot). All my Inktober 2019 drawings can be seen in one album on Flickr.

There is also a thing called Inktober52 which replaces the daily drawings for a month with weekly drawings for a year. I’m not sure if that first started in 2020, but that’s certainly when I first gave it a try (and the first year for which I can find a prompt list online). Unfortunately, as we all know, 2020 pretty quickly became pretty hectic and I didn’t get beyond the first 9 weeks of drawings. Still, the ones I did are available in another Flickr album. This time I again mostly worked with black ink on white paper, but with a range of different pens and occasional brushes. The sketch that ended up being my final one of the series was done in multiple colours (using non-waterproof ink and a wet paintbrush to provide a bit of blending) and I think I was intending to do a bit more work with diferent colours and quite possibly try a few other things as well.

By last October I was completely out of the habit of drawing so I don’t think I even considered doing Inktober, and it was much the same for this year’s Inktober52. However, having restarted with my drawing in the last couple of months I was keen to give Inktober another go this time round. Initially I was planning to use black ink again, but since I’m currently still trying to get to grips with using Procreate on my iPad, I decided that this would be a great opportunity to get in some extra practice and perhaps to push my explorations in directions they wouldn’t otherwise go. So for me, this year’s Inktober is being done with virtual ink. To keep more or less within the spirit of Inktober, and to provide a bit of focus, I’m restricting myself (at least initially) to the brushes within the “Inking” section of Procreate’s default brush library and mostly working in black on white, but mixing it up a little bit when the subject matter, or my personal muse, calls for other approaches.

So far I’ve managed to do one drawing every day (although I think one of them was finished slighlty after midnight) and I’m putting them all in yet another Flickr album, as well as on Instagram (where my previous Inktober/Inktober52 sketches went as well – in fact, I haven’t yet got round to using my Instagram account for anything else, although I originally set it up with the intention of sharing my Figuary 2019 portfolio there; in the end those sketches just went into one more Flickr album). All being well, I’ll reach the end of Inktober 2021 with a full set of 31 drawings (plus a few extras inspired by them) and a much better handle on how to use my current range of digital art tools.

Brushing Up Again (Part Two)

As promised yesterday, here’s a bit more about my recent adventures with digital art on an iPad using the Procreate app.

I have mostly been practising by doing a handful of simple abstract paintings and more-or-less daily life drawings (fairly quick sketches from photo references). Indeed, one of my motivations to actually get on with trying to learn how to use my new digital art platform (having bought the hardware components, if not the software, several months ago) is the hope that my life drawing classes may be able to restart soon and the attendant realisation that my drawing skills have got some what rusty through neglect in the last year or so (I dropped out of the daily sketching habit around last April and have only done a handful of random sketches since then).

Having begun to get a handle on the basics of using Procreate, and beginning to feel some of my (albeit limited) artistic mojo returning and adapting well enough to the new medium, I decided to have a go at some more painting-styled work.

As my first subject, I selected an avocado plant that’s growing (in a pot) on my windowsill. Here’s what the painting looks like at the moment (it’s probably a work in progress, but I may decide just to quit while I’m ahead):

I started with a rough sketch to establish the basic composition. I then dialed back the opacity of that layer and set up several new ones to contain the painted background, the pot and the plant itself, each with a layer of their own. In each of these I used the “acrylic paint” brush at various different sizes.

My process was quite similar to how I’d approach a painting with actual acrylic paints, and the result is definitely quite a similar style too. It was definitely nice not to have to worry about mixing up sufficient quantities of paint or avoid contaminating one lot of paint with another, nor to have to wash my brushes afterwards or wait for one layer to dry before I could start on the next one. It’s also convenient to be able to go in and rework the background without having to worry about accidentally painting over any of the foreground details and it’s great to be able to try out different options without necessarily commiting to them.

For example, looking at the picture now, I wonder if a little bit of “inking” over the top to provide a bit more definition for some of the leaf edges and other structures might help the overall effect. In a traditional painting I’d have to make a decision and either leave it as it is (no pun intended) or commit to putting pen to paper (and I’m not actually sure how well it work to try drawing over acrylics, though I know it can work well with watercolours). With this digital painting, all I’d need to do (I’m not sure if I actually will) would be to add a new layer, do the drawing on there and if I don’t like it I can delete, or even just hide, it. And I’m not just limited to one experiment either – I could try a bunch of different things and then select the one(s), if any, that work best.

I don’t think I’ll be getting rid of my real paints and brushes just yet, but I suspect that I may well be doing the majority of my artwork (or at least the painting) with digital media from now on.

(And in case you’re wondering, I actually wrote this last night hot on the heels of the previous post – I didn’t get up bright and early to write and post it and I may in fact still be in bed!)

Brushing Up Again (Part One)

A few months ago, I decided to get myself an iPad. There were several reasons for this but one of the main ones was that I wanted a better platform for digital artwork than my cheap and cheerful Android tablet. I decided to push the boat out a reasonably long way and get myself a 4th generation iPad Air. If the experiences of other iPad users I know are a fair guide, Apple hardware seems to last a pretty long time and athough newer, more powerful models come out frequently the older ones continue to work and be well supported, so by getting a new one now I hopefully have a device that will keep going and be useful as more than an expensive paperweight for for a long time to come.

Some kind of stylus is pretty much required for any serious digital artwork on a tablet and the Apple Pencil is, by common consensus, agreed to be the best by far of the options available for the iPad. Unsurprising, as it’s made by Apple themselves. However, it has a correspondingly large price tag and my budget didn’t stretch to getting one of those at the same time as my iPad. Instead I got a relatively cheap stylus (about £15, as I recall, compared to over £100 for a 2nd generation Apple Pencil or around £80 for a 1st generation one that would still work but have some limitations). It’s not quite as fully featured and, probably most crucially for drawing, not pressure sensitive but certainly enough to get me started and learn the basics of the apps I’ll be using. At some point I may invest in an actual Apple Pencil.

Initially I installed Autodesk Sketchbook, a free app that is also available for Android (and, I think, a bunch of other platforms, not all tablet/phone based). I have used this on my Android phone and tablet and got on ok with it, though I never really got comfortable with the interface. My experiences with it on the Mac were slighlty better, due to a bit more screen real estate (certainly compared to my phone), a better stylus and much more responsive handling than my old tablet. Still, I didn’t find myself particularly loving it and wanting to do lots of drawing.

A few weeks ago I decided to take the plunge and buy myself a copy of Procreate, a very highly regarded (and iPad exclusive) drawing app that costs the princely sum of £8.99 or so (a one-off payment). Most reviews I read that compared it to Autodesk Sketchbook said that Procreate was a more powerful bit of software but harder to learn. Undaunted I purchased it anyway and was pleasantly surprised to find that, for me at least, the interface is much more intuitive and the overall drawing experience much more pleasant. This isn’t to knock Autodesk at all – that is also a very capable app (I don’t want to damn it with faint praise by adding “especially considering the price point”) and I’m sure if I devoted enough effort to it I could learn it well enough, but I think Procreate is the one for me.

There is plenty still to learn of course, and lots of scope for frustration along the way (even just with respect to itself, let alone my own artistic abilities or lack thereof). For instance, one evening I finished a sketch I was particularly happy with and then, noticing that it was showing up in my gallery in landscape format (when it was supposed to be a portrait format sketch), I tried to rotate it by changing the canvas size and inadvertently ended up cropping off the entire top half of the sketch. For some reason, this seemed to be a one-way process and it wouldn’t let me undo the change, which is usually possible with digital editing and is one of the major attractions of it compared to traditional media. I ended up just having to settle for half a sketch. Fortunately, soon after that I discovered how to rotate the images in the gallery without having to change the canvas size, so I should be able to avoid making that particular mistake again, though I’m sure there are plenty of others still to be made.

I was going to go on to talk a bit more about the actual creative process and put in a picture of the painting I’m currently working on, but this is getting quite long already so I’ll save that for another day.

P.S. I originally entitled this post simply Brushing Up, and then made it Brushing Up (Part One) when I realised it was going to be a two-parter (at least). After I published it I had a read back through my earlier art related blog posts and discovered that the very first one was also called Brushing Up. I have therefore reamed this one. Actually, the first line of that post is almost as applicable now (although it hasn’t been quite such a long gap this time): “After far too long a gap, I have recently begun to draw and paint again.”

Still Life

We’re now about half way through 2019 and although my creative drive has subsided quite a bit since the start of the year I am still regularly drawing and occasionally painting (and even doing random things like soap carving).

The two mainstays of my drawing at the moment are a self-imposed project to try and do at least one sketch of a hand each day (more about that, probably, when I get to the end of my designated hand sketch book and most likely bring that particular project to a close – not many pages left now so it’s set to be within the next few weeks) and my weekly life drawing classes.

Since I started attending the life class in January (the second week of the month, when it restarted after the Christmas break), there has been one week when the session was cancelled (annoyingly, that was the week I’d already postponed a dentist’s appointment to avoid missing the session!) but I have been able to attend at least some, and usually pretty much all, of the session every week that it has been on.

That makes for a total of 24 sessions or around 50 hours of drawing (we get in a bit more than 2 hours of drawing in a typical 3 hour session, but I’ve had to miss a few chunks of sessions, so I may only have done about 40 hours of figure drawing from live models so far this year), with 9 different models (6 female, 3 male). I’ve also done quite a bit of drawing from Croquis Café resources and other photo / video references, as well as some bits of figurative (or semi-abstract) work based on my sketches from the life classes, so it’s fair to say that this has accounted for a substantial chunk of my artistic activity this year.

It seems quite appropriate that the 6 month mark corresponds with the point at which I’ve reached a total of more than 300 photos of my life drawings posted to my Flickr album. These are all either things I’ve drawn or painted at the life classes themselves or, in a few cases, things I’ve drawn, painted or carved at home based on sketches from the life class. There’s not an exact one-to-one correspondence between the photos and individual drawings and I haven’t kept a careful account, but I probably have done around 300 sketches (ranging from a few seconds to about half an hour each) in the life classes so far, and perhaps about a dozen other pieces of work directly based on them. The skills developed in the process have doubtless had a significant effect on my other drawings and paintings (and perhaps beyond) too but that’s even harder to quantify.

On the whole I’d say my drawing skills are gradually improving, although the quality of my sketches can vary quite a bit from one session to the next and often from one pose to the next. Perhaps most importantly, it has been a great deal of fun.

I’m looking forward to continuing with the life classes for as long as possible. And it’s only just over a month now until the Oxford Summer School, where I’ll be doing a 3 day course on “Drawing from dance”.

Figuary is finished (for now)

Figuary 2019 is now over.

As I have mentioned once or twice in recent posts, Figuary is a daily life drawing challenge set by the Croquis Café and LoveLifeDrawing YouTube channels, running through the month of February. Serendipitously, I discovered these channels (or more strictly speaking, I restarted drawing after a long gap, joined a weekly life drawing class that happens to take place in the building where I work, blogged about it mostly because I accidentally came up with a too-cool-to-ignore title for a post on the subject and was subsequently directed to the channels by my brother Wulf — I don’t know how or when he first came across them but I’m very grateful for the pointer) just before the first ever Figuary took place.

I have very much enjoyed watching the daily instructional videos from LoveLifeDrawing and trying to put the lessons into practice with the daily pose videos from Croquis Café. My results were quite variable from day to day, but I think there was a definite improvement in my drawing skills over the course of the month. I managed to keep up with all the daily videos and draw all the poses from each one (as well as a couple of extras on a day when I got fed up with the model moving too much and ended up pausing the video!). Having switched from a single page to two pages of my (A3) Figuary sketchbook each day from about the middle of the month (when they tackled the subject of drawing on a larger scale – I’d already given myself an extra page on the second Sunday to allow for the extra poses in the longer session that day) I ended up filling 43 pages of my sketchbook, as well as half a dozen A5 sheets on the first day (when I didn’t have my sketchbook ready — I did another set of drawings from the same video the next day), doing a total of 192 sketches specifically for Figuary, not counting all the ones I did in my life class or from the back-catalogue of Croquis Café videos or other sources). As well as putting copies of all of them in my general Croquis Café album on Flickr, I have now set up an album specifically for my Figuary 2019 drawings (I have another one for my life drawings done at my actual life class and one for miscellaneous figure drawings based on other sources)

Now that Figuary is over, I may not do life drawing every day, but I certainly intend to keep up my daily drawing habit. As for the figure drawing, I’m planning at least to keep going to my weekly life class for as long as possible (as drawing from life beats drawing from videos hands down in almost every respect) and to keep up with the new figure drawing resource videos appearing weekly at the Croquis Café. I’m also due to be attending the Oxford Summer School this year (at the end of July) to have 3 days of instruction on drawing from dance, so I’m hoping that the life drawing (and general drawing) practice I have done and will have done by then will give me a good foundation for that.

I gather they are planning to run another Figuary next year (presumably sometime between the months of January and March!) and I very much hope they do. If so, I fully intend to participate again. And since it’s due to be a leap year, I guess we may even get 29 days of drawing instead of just 28.

Deja Vu

I said a couple of weeks ago that I wouldn’t blog about my life drawing sessions again unless anything particularly noteworthy happened.

Well it did (near enough for me, anyway) today.

Last week we had a new model (new to our session, not new to modelling). This week we had her again. This was somewhat unexpected as we had been told that we would be having the model with whom we started the year (and my very first session), but she cancelled and fortunately last week’s model was available instead.

The end result is pretty much the same from my point of view in any case — a second opportunity to draw a model I have previously drawn. I’ve already had that experience with some of the Croquis Café videos but this was the first time in my 21st century experience of actual life classes. Actually, I was quite looking forward to redrawing the first week’s model, since I think my drawing has improved quite a bit since then and the progress is less noticeable since last week (in fact, I think I got better sketches then than today!). Not to worry, as it’s very likely we’ll be seeing both models again before too long (as well as the others I’ve drawn so far, and doubtless several I haven’t).

Speaking of Croquis Café, I have a cunning plan which will be much easier to do with the videos than it would with a real live model. In a few months’ time (or perhaps sooner, though I don’t want to make it too soon) I intend to revisit some of the videos I started with, and then compare my first and second sets of drawings of the same scenes. I’d expect to see  significant improvement from one set to the other. With live models, it may be possible to get more or less the same pose (and in fact, one of our poses today turned out to be quite similar to one from last week, though I was viewing it from a different angle) but it would be relatively hard to get a complete set and to ensure that they were drawn for the same duration and from the same position, with the same lighting conditions in both cases, while the videos are infinitely repeatable.

Also on the subject of Croquis Café I wanted to put in a brief plug for Figuary. This is a month long initiative put together by Croquis Café and LoveLifeDrawing, with the aim of providing daily life drawing instruction and practice for the 28 days of February (check out this earlier post or just google them if you want links). Each day, there is a short (roughly 3 or 4 minute) instructional video from LoveLifeDrawing and a pose video from Croquis Café to provide practice opportunities for the techniques discussed in the other video. The pose videos have a different model each day; I’m not sure if we’ll be getting 28 different models, but most of the ones we’ve so far had are familiar to me from the regular CC figure drawing resource videos I’ve been working through. Most days the videos are a bit shorter than the regular CC videos  (about 18 minutes), with 6 poses each day (three 1 minute ones, two 2 minute ones and a single 5 minute one to finish) but the Sunday videos are the same format as the regular ones (24 minutes, 10 poses, with 5, 4 and 1 each of the three durations respectively) — in fact, the Sunday videos are the regular videos but have just been rebranded for Figuary.

So far I’ve managed to work through all the Figuary videos on the appropriate day, and I’m just about to do the ones for today. Hopefully I’ll manage to keep that up for the rest of the month too, so my figure drawing (and my general drawing, for that matter) should continue to improve quite a bit over the coming weeks.

Incidentally, I’m putting photos of all my sketchbook pages from Figuary into the same Flickr folder as my other Croquis Café drawings but if you just want to see the Figuary ones you should be able to get them here.