'78 paper now online: Renaissance Art meets the Computer
Charles Eicher
thermofax copy of a computer graphics paper from 1978. I've been looking
for this particular paper for several years, it is probably the one paper that
turned me towards computer graphics as a profession as well as my
personal artistic medium. It is a wonderful little time capsule of computing
in both the Renaissance and the mid 1970s.
I encountered this paper in 1978 when I was an undergrad art student,
and had worked with computers graphics on a primitive level with pen
plotters and computer output microfim, and I had built my own Sol-20
microcomputer. I had even displayed computer graphic artworks with my
Sol, and scared all the traditionalis art professors by demonstrating odd
animations produced in Logo with Turtlegraphics, and declared this was
the wave of the future.
At the same time, I was studying perspective drawing and mechanical
drafting with T-square and triangle, and learned of some obscure areas
of projective geometry known as "anamorphosis." In the early
Renaissance, just after the discovery of the techniques of perspective,
some artists explored ways of distorting images with projective geometry.
The most famous example is a hidden image of a skull in the Hans
Holbein painting "The Ambassadors." When viewed from straight ahead,
there appears to be a smeary image across the bottom of the painting,
when viewed from an oblique angle, you can see the smear is a skull.
There are many variations of anamorphic images, some were intended to
be viewed in cylindrical or conical mirrors. Another use for the anamorphic
effect is in architectural decoration. There is a hallway in the Vatican with
an arched roof with a fresco on it with anamorphosized drawing of a
square roof. When you walk down the hall, it seems like the roof is
arched, until you hit the spot that the image is projected from, and then it
suddenly snaps into focus and for a moment the curved archway seems
square. Very clever.
Well.. all of this and more is discussed in the paper I have just scanned
and posted. It discusses the math behind anamorphic projection, and as
a bonus, it has a free prize! In particular, I recommend you print out the
last page and cut out the plotter output, and tape it together into a little
cone.
The paper is about 1Mb and in .pdf format. The doc contains 10 pages of
300dpi bitmap scans, cropped tightly to save memory (and .Acrobat did a
wonderful job of compressing 8Mb of scans into 1Mb of non-lossy
bitmaps). It is optimized for laser printer output, but should read well
onscreen if you zoom in. Sorry for the quality, these copies were really
faded, I had to do a considerable amount of work to clean them up.
BTW, I particularly love the wonderful typewritten formatting with tricky 2-
column formatting. Looks like it was produced on ATS/360. You don't see
documents that look like this anymore.
Charles Eicher
Ooops! It would help if I posted the URL for the doc. Sorry for the omission.
Charles Richmond
>
> [snip...] [snip...] [snip...]
>
> At the same time, I was studying perspective drawing and mechanical
> drafting with T-square and triangle, and learned of some obscure areas
> of projective geometry known as "anamorphosis." In the early
> Renaissance, just after the discovery of the techniques of perspective,
> some artists explored ways of distorting images with projective geometry.
> The most famous example is a hidden image of a skull in the Hans
> Holbein painting "The Ambassadors." When viewed from straight ahead,
> there appears to be a smeary image across the bottom of the painting,
> when viewed from an oblique angle, you can see the smear is a skull.
> There are many variations of anamorphic images, some were intended to
>
discussed on the following WEB page:
<http://www.stanford.edu/~dmccune/anamorph.html>
An anamorphic lens is what allows movies to be projected in super
wide-vision...
--
+-------------------------------------------------------------+
| Charles and Francis Richmond <rich...@plano.net> |
+-------------------------------------------------------------+
Charles Eicher
I am glad to see that at least ONE person looked at this paper. Jeez, how could
you pass up a math paper with illustrations from Durer, Leonardo, etc. But it's
my own fault. Sorry for not posting the URL, which I will repost again:
http://soli.inav.net/~ceicher/anamorphosis.pdf
I should point out that an anamorphic lens as used in movie cameras is only a
one-dimensional anamorphosis, it merely stretches the X axis of the frame.
Leonardo's invention was similarly 1-dimensional, only later research in
Perspective gave a more comprehensive understanding of the math. The illusions
used in the later Renaissance were much more sophisticated, involving
projections onto curved surfaces, or reflections off complex mirrors like cones
or cylinders. If there is anyone with actual scholarly interest in this subject,
I have a copy of the extremely rare book "Hidden Images" which is the primary
source for this math paper.
My favorite anamorphosis story comes from Fra. Pozzo, a Jesuit priest and the
popularizer of this technique for architectural ornamentation, due to his
publication of a book on the math and geometry of anamorphosis. Pozzo is famous
for producing a trompe l'oeil ceiling painting for a chapel ceiling in Italy.
The priests wanted a tall towering dome atop their chapel, but the tower would
have cast a shadow on their library. Pozzo volunteered to produce a painting
that showed a tall dome when viewed from inside the chapel near the center. The
painting is flat, but appears to go up over 100 feet. When the chapel was opened
to the public, Pozzo's painting was presented with no explanation, he wanted to
see if his illusion could fool the experts. An architect protested that the
post-and-lintel construction used in the "dome" walls was built improperly and
the tower would collapse within months. Pozzo boldly announced that he would
personally pay for reconstruction of the dome if it should collapse.
Anyway, when I was just a young lad and first started fiddling with the math in
this paper, I could envision a day when it would become simple to produce
anamorphic projections. But I never had a clue that it would become as simple as
applying the "free distortion" or "polar coordinates" plugin in Photoshop.
Having constructed a couple of these images via conventional means (Tsquare,
triangle, french curve and protractor) I can really feel for those old guys and
their intense devotion to an obscure mathematical trick. It was intensely
tedious to produce cylindrical projections, even with my post-Renaissance
high-tech gadgetry (a slide-rule).
Brian Huntley
>
>
Thanks for posting that.
My grandmother told me once of seeing a painted tray with a distorted
image that was viewed by placing a silver cylinder (tea pot?) on the
tray and looking at the reflection. Probably English. Some of her
family worked as porcelein painters, but I think it was an oil
painting by the way she described it.
Computers do tend to take the fun of of things, don't they?
Charles Eicher
brian_...@hotmail.com says...
>
>Charles Eicher <cei...@Inav.net> wrote in message
>news:<a4mnd...@drn.newsguy.com>...
>> In article <3C6ED904...@ev1.net>, Charles says...
>> >
>> >Charles Eicher wrote:
>> >
>> http://soli.inav.net/~ceicher/anamorphosis.pdf
>>
>>
>
>Thanks for posting that.
Judging from another emailed remark, I should clarify: I didn't write the paper,
I just pulled it out of my ancient files. The author and source are marked, I'm
not really sure what book I made copies from, I think "Computers and Art" was an
early SIGGRAPH publication.
Oh man you should see these old thermofax copies, that is another lost media. I
remember we used to do a lot of xerography, thermofax, and other "copier art"
projects back in those days.
And ooh that word processing.. notice the italicized footnotes and captions,
which were an incredibly huge pain to produce because the IBM Selectric "golf
ball" type element had to be switched out on demand to an italic element. The
output would just stop while the program waited for you to switch balls, then
you hit a key and it resumed printing in italics. Then it stopped and you had to
switch back to the regular type ball. I could never quite get over my uneasiness
at putting my fingers into the middle of a Selectric terminal that threatened to
roar back to life at any moment.
>My grandmother told me once of seeing a painted tray with a distorted
>image that was viewed by placing a silver cylinder (tea pot?) on the
>tray and looking at the reflection. Probably English. Some of her
>family worked as porcelein painters, but I think it was an oil
>painting by the way she described it.
You should see the book "Hidden Images" that is cited in the appendix of that
paper. I have a battered old copy, it comes with a sheet of mylar that you roll
up into a cylinder and view the full page illustrations. It shows many examples
of anamorphic painting, some of them had wooden picture frames so they'd look
quite similar to a tray, like you describe. Some of these images were quite
accurately projected, some were crudely drawn by looking in the mirror and
reverse painting and the distortions are quite obvious.
>
>Computers do tend to take the fun of of things, don't they?
Quite the opposite. I love combining the oldest tech with the newest, it's been
my specialty as an artist for many years. This projective geometry stuff is the
foundation of all modern computer graphics systems. Have a few tricks like this
in your reptertoire, and your computer graphics turn out way better than
non-artist's work. I suppose it's my turn to write a paper about this..
Neil Barnes
> You should see the book "Hidden Images" that is cited in the appendix
> of that paper. I have a battered old copy, it comes with a sheet of
> mylar that you roll up into a cylinder and view the full page
> illustrations. It shows many examples of anamorphic painting, some of
> them had wooden picture frames so they'd look quite similar to a tray,
> like you describe. Some of these images were quite accurately
> projected, some were crudely drawn by looking in the mirror and reverse
> painting and the distortions are quite obvious.
>
I have seen reference - on an antique show I believe - to circular
anamorphic portraits of out-of-favour kings and other political figures.
These were disguised as (painted on) an artist's palette, and to the
untutored eye just looked like splodgy colours. Place a suitable reflective
object in the centre - I think it was demonstrated with a glass - and you
instant seditious paintings. I *think* the time scale was around that of
Oliver Cromwell.
--
I have a quantum car. Every time I look at the speedometer I get lost...
barnacle
http://www.nailed-barnacle.co.uk
Charles Richmond
has a picture of an anamorphic painting in it, with some
explanation. Also, it has a nice photo of an IBM 705 console
with a chess board in the foreground, and some guys supposedly
running a chess program.
Charles Eicher
nailed_...@NOSPAMhotmail.com says...
The Hidden Images book has plenty of examples of disguised pictures from across
the spectrum, of course porn was a common subject. The book even includes some
interesting Japanese "shunga" prints in cylindrical projection.
But I'm more interested in the architectural applications. The book shows
several interesting designs, like a tunnel with slightly converging sides and a
floor with a "square" grid of tile in distorted perspective. As you pass through
the tunnel in one direction it seems foreshortened, pass the other way and it
seems elongated.