Learning Outcome 15

Tutorial Group mixed media/digital Bob Tate 2020

Below is the relevant extract from my learning agreement

Examine complex problems in your area of study and articulate a range of solutions  

There are many complex problems; and there is potentially a lifetime of study possible. I intend to focus on three core questions.  

How can projection mapping communicate the artist’s vision to an audience without the technology overwhelming the viewer or becoming a mere distraction?  

The challenge here is to make the art, not technology, the magic which transforms the audience’s experience and vision of the work.  

How can more than one projection mapping device be used to enhance an image, or present a 360° 3D image?  

Conventional projection affords the artist the option of additive (overlapping) projection fields to increase luminosity (albeit in a non-analogue fashion). Projection mapping is largely unresearched in respect of “piggy-backing” or projecting “scrum fashion”  

How small can you go?  

I know that the minimum conventional projection throw for this technology is currently 45 cm (approximately 18”). However, with mini projector technology, it may be possible to reduce this further. Ideally, I would be able to project onto a single coin.      

How can projection mapping communicate the artist’s vision to an audience without the technology overwhelming the viewer or becoming a mere distraction?

According to the Pew Research Centre (a purportedly non-partisan think-tank in Washington) technological overload is one of the main concerns and threats to well-being reported by contemporary Americans. A 2019 report quotes an unnamed IT academic as commenting

““The grand internet experiment is slowly derailing. The technologies that 50 years ago we could only dream of in science fiction novels, which we then actually created with so much faith and hope in their power to unite us and make us freer, have been co-opted into tools of surveillance, behavioral manipulation, radicalization and addiction.”

Life on MARS

“Sometimes it’s more important to be human than to have good taste.”

Bertolt Brecht

I very much like the idea of a mantra of Manipulation, Addiction, Radicalisation and Surveillance – MARS – being applied to projection mapping as a set of probes.

Let us suppose then, that the techniques of projection mapping have the potential to corrupt any audience, through the MARS effects. can we make each of these facets of technology visible to the audience, so that they can defend themselves, be aware, to challenge art and ideas effectively?

Brecht had lived through the period of Nazi demagoguery and had seen at first hand where such propaganda could lead, so let’s consider adopting a Verfremdungseffekt – the alienation effect, making the familiar strange, in order to jolt an audience into thinking about the issues before them, and not merely be carried along by emotions.

Then, let us consider the Situationist tactic of détournement.

The Situationist movement of the 1960’s championed the term, which is French for “overturning” or “derailment.” It carries echoes of psychoanalitic theory.

Situationism teaches us that one can seek to disrupt the manufactured and pre-digested (in every sense of the word) hegemony of dominant class propaganda.

The very ubiquity of mass media, mass message creates opportunities for subversion of the central message; and the injection of marginalised counter-cultural messages, literally like a virus.

A text already understood or identified by the intended audience is turned upside down, and a new significance is attached.

There are many examples; the current graphic warning labels on cigarette packages are themselves subversions of the original marketing materials and in turn, are parodied in memes.

Détournement creates a cognitive dissonance which unsettles the established schema and invites re-processing of images into new schema. a well aimed détournement can evade rational psychological boundaries, and speak directly to the emotions.

One difficulty in employing Situationist strategies like these, is that they do rely upon common cultural memes; and hence the oppressive cultural assumptions and biases.

Famously, Mary Whitehouse objected to the 1960’s TV program, Till Death Us Do Part by reason of the repeated use of the word bloody; and not because it engaged in the faux promulgation of grossly racist and anti-semitic utterances from the mouth of the character of Alf Garnett, the archetypal bigot.

30th November 1966: British actor Warren Mitchell as Alf Garnett in a Christmas edition of the BBC Television series ‘Till Death Us Do Part’. (Photo by Leonard Burt/Central Press/Getty Images)

Whitehouse completely missed the irony of those comments; whilst the more aware of the audience we able to check their own prejudices against the litmus paper of the retired Tory South London Docker and his progressive and tolerant daughter and her partner.

Mary Whitehouse
PRESS ASSOCIATION photo. Photo Credit PA/PA Archive. Unique Reference No. 1505311

Speight (the writer of the series) then extended the détournement, by making the fictional character Alf Garnett, a fan of the real life Mary Whitehouse.

(A highly pornographic magazine was also published at the time, with her name as title, by David Sullivan).

Whitehouse Magazine

So, using détournement as mechanism for disrupting the accepted signifiers of consumer culture, can be an effective tactic. However, there is always a danger of relying too heavily on technique (and self-congratulation) at the risk of authenticity.

Make the Art Shine Through

The best way to make the artistic content shine through as the focus of the projection, is, of course to have something really interesting and effective to say; and to say it in an interesting and effective way. No amount of polish will create something memorable, moving or indeed disturbing, if the work lacks truth, impact or depth.

So, I propose three simple measures which, when employed, facilitate the creation for best conditions for artistic effectivness.

Reveal, Don’t Disclose

In Ed McBain’s 87th Precinct detective novel series, Mc Bain (aka Evan Hunter) often uses a kerygmatic approach , in writing, to reveal the true nature of a character, within the story.

Ed McBain

I recall one such episode (I cannot remember which story) wherein the protagonist, Steve Carella is dining out with his wife. A boorish drunk customer insists on picking a fight with Carella, who is reluctant to become involved. However, once the point of no return is passed, he ruthlessly and efficiently demolishes the man, before having him arrested. His wife (a pre-lingually deaf woman called Teddy) sees her husband, for the first time; as he really is. The scales fall from her eyes and she is possessed of new knowledge of him; literally a kerygmatic experience.

My aim is to create such experiences in my work, which trump the merely decorative or technological appeal of the projection.

Show, Don’t Tell

Reclining Artist Grayson Perry 2018

It is a truth acknowledged to be universal, that work should display and show its meaning, to the viewer. To achieve this one should seek a point of entry to the work; that part of the whole to which the eye is first drawn, and from which the eye traces the pattern or structure of the work.

One of the great strengths of projection mapping is that the point of entry to the work need not be fixed in place or time; one can create different points of entry, or make the same point appear and disappear at will.

One can also offer up different points of entry, designed to appeal to viewers of different perspectives. Grayson Perry is very good at this; offering up what he calls Easter Eggs (a term derived, I understand form video games) for the “middle classes”- art references within the image, which draw the eye of the artistic connoisseur, in a rather arch manner.

Bonnard draws us into his paintings in a similar way, with objects and colours which are not necessarily obvious at first glance, but which reward the more pertinent viewer with insights.

Whisper, Don’t Shout

I’m a sucker for Soviet Realism, a deeply unfashionable form of propagandistic art, with strong elements of kitsch. Much of it is so transparently unbelievable, that it acquires a kind of patina of classical mannerism; the images are too good to be true, too vivid or so “on message” as to be laughable.

Yet, the execution is often lovingly detailed; and the subjects attract our interest, more for the peripheral details of their live that the actual central theme of the image; the peasant farmers clothes and farming tools; the cautious curiosity of the children; and the no-nonsense attractiveness of the young men and women.

The very best of these images communicates something to the viewer by murmuring the message; not shouting or proselytising Soviet Communism. Only a moron could be taken in by the images of Stalin cuddling little kiddies; but the faces of the children presenting flowers are often well observed.

Whisper, don’t shout.

How can more than one projection mapping device be used to enhance an image, or present a 360° 3D image?  

Unfortunately, the lockdown stymied my intention to explore this element of the project in the studio; so I’ve had to explore multiple projection problems more from a theoretic or technical perspective.

Projection Geometry Basics

Any projector has a Throw Ratio

The Throw Ratio (TR) is the mathematical relation between the throw distance and the image width. The TR tells us what image size can be projected from a set distance.

The Throw Distance (TD) is the distance between the lens and the projected image.

The Image Width (IW) is the width of the projected image.

The formula

Throw Ratio = Throw Distance / Image Width

defines the image size which can be projected from any given distance. For instance, a throw ratio of 2 indicates that for every 100 cm of image width, the throw distance must be 200 cm.

Projectors which can produce a large image at short distances from the screen, have smaller throw ratios.

 

Throw Ratio (Source;Lightform)

Using Throw Ratio

Using the throw ratio equation and its variations is essential when selecting the right projector for your experience — it’s important to consider the positioning of your projector and the size of the image you’d like to project (or the size of the scene you’d like to cover). With the throw ratio equation, you can determine: 

The ideal throw ratio for any given projection

TR = TD / IW  

(Throw Ratio = Throw Distance / Image Width) 

Where to place a projector given its throw ratio & intended projected image size

TD = TR x IW  

(Throw Distance = Throw Ratio x Image Width)

The width of the image the projector will produce (given its throw ratio & throw distance)

IW  = TD / TR

(Image Width = Throw Distance / Throw Ratio)  

Optimal throw ratio calculation

TR = TD / IW   

e.g., To project an image that is 2m wide, at a projection distance of 3m, the projector must have a throw ratio of 1.5 (3 /2). 

(Lightform projection equipment has a throw ratio of between 0.82-1.77).  

Calculating where to place the projector

TD = TR x IW  

e.g., To project an image that is 2m wide using a projector with a throw ratio of 1.5, the projector must be no less than 3m distant.  

Calculating how wide of an image will be projected 

IW = TD / TR  

e.g., Projector with a throw ratio of 1.5 and place it 3m away, you will get an image width of 2m.  

Advanced Projection Geometry

Two core problems confront the projection mapping artist.

Unless one is able to purchase (or lease) powerful projectors (by which I mean equipment with an ANSI lumen rating of over 6000) at a cost of at least £5,000

Firstly, how to extend the breadth of the projection, to provide a panoramic view, using a combination of smaller and less expensive projectors?

Secondly, how to superimpose images from two projector, to enhance the luminosity of the image (particularly during daylight projection)?

As long as it is wide

In my current practice, I’m not likely to seek to make many very wide projections, but I thought I would learn how to, just in case.

To extend the width of a projection, it is necessary to have two projectors (ideally the same make and model) and a merging kit, which comprises of a digital mixer and software package plus a digital camera/scanner.

The kit works very much like a first generation projection mapping scanner. the projectors are set up, and aligned to overlap by at least 10%.

The levels of illumination are adjusted; and the screen display settings for the computer are set for multiple display. The digital mixer is activated, and the camera feed switched on.

The projection areas are mapped and meshed using the firmware; and the projection area defined.

Final tweaking and alignment is completed and the projection proper begins.

Position of scanning camera and projectors





Schematic diagram for merged projection

Seeing Around Corners

Of more interest and direct relevance is the ability to project not only 180 degree three dimensional images (i.e. a hemispherical projection) but to complete the sphere and achieve true three dimensional perspectives.

To perform this feat, using traditional methods this, one needs at least FOUR projectors arrayed thus:

Three dimensional projection using conventional projectors

The same principle of overlapping and blending edges using software and fiddly mapping adjustments applies.

However, using Lightform projection mapping, I anticipate that only two projectors would be needed (because the three dimensional mapping is integrated int the function) and therefore each projector will map a perfect hemisphere.

Although crude, this image is broadly equivalent to a quarter of a sphere. Note the projection wraps around to the vertical midline

Brighter and Brighter

The penultimate question I posed myself in this area was, how does one increase the illumination, – without breaking the bank?

I found the following hints, on a professional projection site on the internet

Cover as many windows as you can. Unless you are projecting at night, sunlight is a more powerful competitor for your projector’s LED light source than you might realise.

Turn off as many lights in the room as possible. At a minimum, turn off any light that reflect off of the screen. This will help make better use of the limited light output from your projector.

Move the projector closer to the screen so that it generates a smaller image. LED projectors generate the same amount of light, regardless of the size of the screen. Smaller images will appear brighter since you are placing more light on each square inch of the image.

Activate the projector’s high-brightness mode. Generally speaking, “Bright,” “Dynamic” and “Presentation” modes will give you greater light output. At the same time, turning off the projector’s “Eco” modes will also increase lamp brightness.

Install a high-gain screen. High-gain screens are made of special materials that focus the light that is projected and reflect it with higher brightness. The drawback to using a high-gain screen is that its benefits are only clear when viewed from a relatively narrow angle. People with a head-on view will receive a much better image than they would with a normal screen, while people who are off to the side will see a much dimmer image than they would with a normal screen.

The Illuminometer (light meter)

Illuminometeres are handy gadgets for measuring ambient light. Mine cost £40 from Amazon, and is worth its weight in gold.

Light is measured as follows.

  • Candela — intensity of light emitted by a source in one particular direction.
  • Lumen — quantity or flux of light emitted by a source. This takes into the account that most lights (like a candle) are essentially omnidirectional and shoot light out at lot of different angles
  • Lux — a measurement of lumens when applied to a surface area or 1 lumen/sq. meter. Light gets dimmer as it is spread out over a larger area
  • Foot-candle — related to lux, but uses the imperial system of measurement instead. 1 foot-candle = 1 lumen/sq ft. = ~10lux
  • Nits — similar to lumens, but used more as a brightness measurement for display devices like smartphone screens and monitors where there isn’t a single point of light, but rather a field of light.

Example lux readings from wikipedia:

  • Moonlight Night/Starlight — 0.0001 lux
  • Full Moon, Clear Night — 0.36lux
  • Home lighting — 50–250lux
  • Overcast Day — 1000lux
  • Direct Sunlight — 32,000–100,000lux

Projecting Indoors

Assume near ideal conditions; a pitch black room, 1,000 lumen video projector covering a square metre of surface area, and the black level is 0 lux and white is 1000 lux.

If the ambient light in the room to 250lux by turning on the lights, the black level on the surface area now starts at 250lux; but white is still 1000 lux. Contrast has gone down and the image will look pale and watery.

If the ambient light starts to rise to around 750 lux, the black levels fall rapidly, and one can hardly see the projected image at all.

Shady Outdoors

If you are working in daylight say 10,000 lux. To achieve similar contrast to the interior projection, one would have to start with a 11,000 lumen projector projecting a square metre. The black point is already at 10,000 lux surface and white is the brightest spot of our 11,000 lux projection.

Physiologically, the projection becomes increasingly difficult for our retinae to see and our cortex to process. The image glares and irritates the vision.

Bright Daylight

A bright sunny day at the beach and 90,000 lux hits the screen from the blazing sun.coming from our screen surface just from the sun. Standard industrial projectors cannot manage more than 20,000 lumens – so projection is impossible.

To stack or not to stack?

Can we shine more than one projector on the same spot, and double the illumination?

Projector stacking

Over illuminating doesn’t work by simple addition. Just because there are double the lumens coming from these projectors doesn’t mean it is perceptually twice as bright.

Two standard projectors can be stacked; but the mapping effects may be difficult to align.

What’s The Catch?

The catch is, you cannot project black; anti-photons only exist in the Hadron Collider. There is something like a 25% improvement with doubling the illumination; but contrast suffers badly.

Commercial projections of great size and high luminosity are actually made up of LED walls, not projections; but in the small gallery spaces and darkened public areas I seek to project in, 6000 ANSI lumens should be enough – and that brings the costs down to a less eye watering (forgive the pun) £2,500 total.

How Small Can You Go?

The world’s smallest Kalashnikov Anatoly Konenko Museum of Miniatures Montalimar

We can now calculate the necessary characteristics of a projector that will project an image on say 1 cm width.

So, in order to project an image that could fit onto a coin, from a short distance, we need to apply the image width formula;

IW = TD / TR

1cm =50cm/50

Does such a projector exist?

The short answer is, no. The minimum width for commercial projectors is about A4 (210 x 297 mm).

A Pico Genie projector (see below) has a throw ratio of and can project small images as low as 120 mm x 120 mm in sharp focus with an ultra bright image just 10cm away from the screen, or roughly A6 size.

Pico projector in operation

Not quite a solution….

So, if I were to take my standard projector, with a throw ration of say 1.7, could I project through a convex lens (or multiple convex lens) to reduce the size of the projected image?

I had a look at some optical physics resources and came up with the following answers.

One single convex lens, designed to shorten the focal length, would create a lot of chromatic aberration.

Chromatic aberration is the rainbow effect created when light passes through a prism, and is bent; light waves of differing frequencies are separated by dispersion, and a spectrum of colours, not pure white light emerges.

Cameras are optically engineered to overcome chromatic aberration, by fusing two or more lenses made of glass of differing refractive properties together into a compound lens, where the net result is coherence of the beam of light arriving at the sensor, from the object being photographed.

To replicate this effect, (in reverse) with a lens system, you would have to move the lens very close to the projector; and equally very close to the surface being projected onto, which might well destroy the intended visual effect. To add to the difficulties, using a lens at distances very close to the focal length of the lens itself creates internal distortions, so an aspherical lens is required to overcome yet another set of distorting refractions.

Conclusions

I have not found a complete solution, as such; but borrowing from my macro-photography experience, I experimented with using a telephoto lens mounted in reverse and stuck onto the lens of the projector with black duct tape.

The projector failed to project the image, although a smudge of light did emanate from the lens, in darkened room.

I think this is still theoretically possible, but impracticable, with the equipment at my disposal.

The only other option I can think of, at this time, is to convert the images that I was intending to project into vector files, using Adobe Illustrator, shrink them down, and projecting through Lightform, onto a 1cm square surface.

At the time of writing, this option is yet to be explored.

Watch this space…

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