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Vermeer’s Secret Tool: Testing Whether The Artist Used Mirrors and Lenses

177 points by shawndumas 13y ago

gus_massa 13y ago
> The brightness of any surface becomes exponentially less bright the farther it is from a light source, [...] Is this true? The brightness decays quadratically with the distance, so I guess that the reflections decay also quadratically not exponentially.
- dfc 13y ago
  Sadly I think the answer is, "according to the article it is true." I doubt many HNers have access to high resolution scans of Vermeer interiors. Until someone else repeats Jenison's analysis of the paintings we will have to take his word for it that this is an accurate description of Vermeer's use of light.
  - jey 13y ago
    But this isn't a question about Vermeer's use of light, it's a question about the physics of light and the psychophysics of visual perception.
- RBerenguel 13y ago
  Brightness decays quadratically, but I'm not so sure about luminance (which is supposedly what the author is referring to.) Edit: actually, luminance depends only on angles. But since the perceived brightness of a reflected source is not a point-light source, I still don't know how it all ties together.
- applecore 13y ago
  Visual perception of luminance decays exponentially, according to the strongest distinction.
  - jmount 13y ago
    I think it may be more accurate to say perceptual description of luminance may be exponential (that humans report the difference from 1 to 1/2 as being the same as 1/2 to 1/4). But I think this is all irrelevant if you are trying to reproduce tones correctly (other than it says the error-model is relative error on tones). So I would say it takes a very labored reading to think of the article statement as correct (as light falls of 1/R^2 not exponentially). But that also makes the article's point: if you are painting what is there you are more immune to wrong assumptions.
    - maaku 13y ago
      Not necessarily. If you are making a painting, you don't have the ability to make some sections literally brighter (higher luminescence) because you don't really have control over the lighting conditions, and oil paints only give you so much ability to adjust reflectance. So what you do is subtly adjust things like tone, texture, detail or technique to 'trick' the human perceptual system into thinking the difference is there. These tricks are what imparts that life-like quality into the old master's works.
  - jacobolus 13y ago
    The term “luminance” refers to a physical quantity, the intensity of the light. It can be measured in candelas/square meter. The relevant technical terms for the perceptual attributes of a color are “brightness” (which is the perception of how bright something is on an absolute scale given current adaptation of the eye/surroundings), and “lightness” (which is the perception of how bright something is relatively, taking into account knowledge of the scene lighting). Luminance (light intensity) is going to fall off with the square of distance. Brightness/lightness do not have an exponential relationship with luminance. The curve is (very) roughly like a square root. In any event, the article was clearly mistaken about this point. It’s a fairly trivial mistake though. Vanity Fair’s fact checkers probably didn’t bother to ask an optics / color expert about the statement.
- jwmerrill 13y ago
  Brightness decays exponentially for light traveling through smoke: https://en.wikipedia.org/wiki/Beer–Lambert_law https://en.wikipedia.org/wiki/Beer–Lambert_law. But I think the article author probably just messed up.
- podperson 13y ago
  No. But when journalism, art, and science intersect, expect casualties.
jere 13y ago
That was fascinating. I would have preferred some more details on the evidence found during this that a camera obscura actually was used. I suppose not having it makes this article a pretty good teaser for the documentary.
- anonymousDan 13y ago
  There's a wonderful book by David Hockney called "Secret knowledge: recovering the lost techniques of the Old masters" where he lays out some pretty compelling evidence for this idea. It's also beautifully designed, as you might expect from Hockney. I keep meaning to try out some of the techniques mentioned to see how well they work but haven't got round to it yet.
  - podperson 13y ago
    The book is great and I'd say the case he makes is pretty water tight (and I say that as someone who wasn't much of a Hockney fan going in, and was very resistant to the idea that some of my favorite artists "cheated" ... but of course artists always "cheat" -- their goal is produce their artwork, not follow some arbitrary set of rules on how to get there).
shashashasha 13y ago
There's also this recent Kickstarter, the NeoLucida, that was all about remaking similar lens / optic devices artists and painters used in the past: http://www.kickstarter.com/projects/neolucida/neolucida-a-portable-camera-lucida-for-the-21st-ce http://www.kickstarter.com/projects/neolucida/neolucida-a-po...
- fennecfoxen 13y ago
  Less kickstarter-y webpage: http://neolucida.com/ http://neolucida.com/ I have one of these. It arrived recently; I haven't really tried it yet, but will soon. Wikipedia: http://en.wikipedia.org/wiki/Camera_lucida http://en.wikipedia.org/wiki/Camera_lucida -- it notes the basic optics were described in 1611 by Kepler.
- pg 13y ago
  I have an antique camera lucida, and it is startlingly effective.
  - selmnoo 13y ago
    You use it to draw/paint? Can you please share something you've done? I'd very curious in seeing anything you've painted with it.
nathanallen 13y ago
> I’ve got a file of counterarguments to my own theory Thank you for having scientific integrity. Falsifiability for the win.
wrongc0ntinent 13y ago
Hockney's book is great, but for a quick and entertaining look at the theory, there was a (BBC I think) documentary with the same title. Probably on iPlayer and YouTube by now, covers more than just Vermeer (no links since I'm not sure about the copyright status.)
pbhjpbhj 13y ago
>"But no one understood exactly how such a device might actually have been used to paint masterpieces." // Seems a stretch. I vaguely recall seeing a documentary - perhaps many years ago, probably on the BBC - on Vermeer's "The Music Room" and how it was understood to be created using an optical system [camera obscura?]. They showed a replica being used to trace an image. Related http://www.math.nus.edu.sg/aslaksen/projects/MC-CL-Vermeer-abstract.pdf http://www.math.nus.edu.sg/aslaksen/projects/MC-CL-Vermeer-a... uses the assumption of the accuracy of the dimensions to establish two of Vermeer's painting were likely done in the same room.
- simonh 13y ago
  Thats close, but not exact. The difference is in the technique of using partial images of the subject overlayed over the painting image, to get the colours and overall colour and lighting gradients matched exactly, at a fidelity the unaided eye wouldn't be capable of. The trick of matching the patch so closely that the edge of the mirror disappears is the real secret. A straightforward over-painting projection of the whole subject wouldn't help with that.
CamperBob2 13y ago
Interesting article (if a bit clumsily written) but I don't understand why it's so controversial. It should be pretty easy to tell if a photorealistic painting was made with mechanical or optical aids. There will be small positional errors in the image either way -- places where the perspective is almost but not quite perfect. The magnitude and direction of the errors (and how they accumulate) will be very different compared to those in a freehand painting, and shouldn't be too hard to analyze.
- wrongc0ntinent 13y ago
  It's not that easy, for a few of reasons. One is the establishment (no better word for the mixture of subjectivity, entitlement, money, and fashion in the art world). Rewriting art history is frowned upon unless it makes the genius artist look like a greater genius artist. Applying a scientific method doesn't work there. Another reason proving this is hard is that some artists do have a great ability to reproduce reality (this was really the most common way to measure an artist's ability before photography came along), but the economy of an artist's technique may reproduce some aspects of reality exactly, while other aspects are just suggested or completely ignored, so you'd need complete consistency. One more reason is that simply seeing a camera obscura image or a similar 2d image may change an artist's technique, they may become aware of things they hadn't considered before (this was the case with linear perspective, look up Brunelleschi's experiment - though nothing as elaborate as a camera obscura). For a camera obscura projection, lighting conditions are very specific, that alone might shift an artist's (mental) focus from being 100% descriptive to being very vague about contours. Basically, you can't "unsee it". Dutch artists from Vermeer's era are perfect candidates to have used lenses, because they had the technology. If you can find undeniable proof anywhere, it's probably there. Really the more proof adds up, the more ridiculous the naysayers appear. Some natural selection would do this field some good.
  - blah314 13y ago
    Thanks, in four paragraphs you gave me a whole new perspective on Hockney's book on this.
SilasX 13y ago
I have a hard time understanding the dilemma here. Could someone please break it down? What difference would it have made to use mirrors and lenses, and how would that have improved his paintings?
- cma 13y ago
  I think they are claiming his view would be split between a zoomed in portion of the screen and the canvas. He could then mix the color until it matched up so closely with the mirror that the line between the two seemed to fade out. I still don't really know what the setup would actually look like and how far zoomed in it was, etc.. You would think the article would have a diagram.
  - deleted 13y ago
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  - deleted 13y ago
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  - dodecaphonic 13y ago
    Tim Jenison was interviewed by Leo Laporte on Triangulation (http://twit.tv/show/triangulation/118 http://twit.tv/show/triangulation/118). They start talking about it between minutes 35 and 36, and he describes the process in a little more detail, including magnification, distance from the canvas and so forth
- egypturnash 13y ago
  Artist here. Okay. Working out perspective by hand is hard. It's a lot of work, that takes a lot of arcane knowledge. So's doing a photorealistic painting of a thing. You have to look at the thing, consider a bunch of relationships of the particular feature you're interested in at this very moment, and transfer those relationships to your canvas. That's a pretty complicated set of habits and brain circuitry you have to build up over a period of years. Tracing an image is immensely easier. There's all the perspective, there's all the proportion relationships. There's all the colors. Right there in front of you. You can spend an hour or two essentially doing manual edge-detection, and then start filling in areas. There's still stuff to learn - how to mix the paint to get the colors you want, how to apply it to the canvas, stuff like that. And if you trace organic stuff too closely, it starts to look stiff and dead. But compared to the amount of skill you have to learn to draw this kind of stuff out of your head? It's nothing. I mean, hell. Take a photo, print it out. Tape it to a sunny window, tape another piece of paper over it, and trace it. Then take that same photo and try to draw a copy of it, without tracing. There will be a huge difference between the two drawings you just made. The one made without tracing will probably have taken a lot longer, and have many more bits erased and redrawn. A lot of modern artists have this weird thing going on with respect to tracing. It's the worst thing ever, they'll say. Tracing another person's work to learn from, or tracing off of a photo, they're different kinds of art crimes, but they're still art crimes. Leaping around learning to break a scene down in your head and reconstruct it from scratch - essentially building a wetware 3D modeller in your brain, really - is considered CHEATING by some people. So Hockney's book on Vermeer's work is essentially saying "dude Vermeer was totally a tracer". Which in many artist's eyes is like calling him Not An Artist. Artists get weird about what is Art and what is Not Art, it's this whole thing that's about as inexplicable to a layperson as a programmer's choice of text editor. By using mirrors and lenses to project an image onto his camera to trace, Vermeer only had to learn the basic painting technique stuff. If he did, if he traced all this stuff, then some people will start saying that his work is no longer Art. It's just Illustration. Which, in the eyes of people who care about this, means that it is a lower, less respectable thing. Now it's just a filter applied to an image, albiet manually instead of via Photoshop or whatever. The truth of the matter (IMHO) is that a lot of the people who will scream bloody murder when someone is tracing are amateurs. Real pros can and will project images and work over them, build reference models in the real world or in 3D programs, and do any damn thing they can to make the hard parts of their work easier, to get all those little details they'd never make up out of whole cloth. I am pretty sure I've repeated myself a couple times here, thanks to the tiny window HN allows to type in. But hopefully this helps. tl;dr: If Vermeer used these techniques then he's a dirty cheating TRACER and is thus not a REAL ARTIST in some people's eyes.
discreteevent 13y ago
On Caravaggio: http://www.webexhibits.org/hockneyoptics/post/grundy7.html http://www.webexhibits.org/hockneyoptics/post/grundy7.html
discreteevent 13y ago
On Caravaggio: http://www.webexhibits.org/hockneyoptics/post/grundy7.html http://www.webexhibits.org/hockneyoptics/post/grundy7.html
001sky 13y ago
The 2006 monograph by the british artist David Hockney (for anyone interested). Secret Knowledge: Rediscovering the Lost Techniques of the Old Masters[1] [1] ISBN-10: 0142005126> http://www.amazon.com/Secret-Knowledge-Expanded-Edition-Rediscovering/dp/0142005126 http://www.amazon.com/Secret-Knowledge-Expanded-Edition-Redi...
- peter_l_downs 13y ago
  This work is referenced many times in the article.

177 points by shawndumas 13y ago

> The brightness of any surface becomes exponentially less bright the farther it is from a light source, [...] Is this true? The brightness decays quadratically with the distance, so I guess that the reflections decay also quadratically not exponentially.

dfc 13y ago
Sadly I think the answer is, "according to the article it is true." I doubt many HNers have access to high resolution scans of Vermeer interiors. Until someone else repeats Jenison's analysis of the paintings we will have to take his word for it that this is an accurate description of Vermeer's use of light.
- jey 13y ago
  But this isn't a question about Vermeer's use of light, it's a question about the physics of light and the psychophysics of visual perception.
RBerenguel 13y ago
Brightness decays quadratically, but I'm not so sure about luminance (which is supposedly what the author is referring to.) Edit: actually, luminance depends only on angles. But since the perceived brightness of a reflected source is not a point-light source, I still don't know how it all ties together.
applecore 13y ago
Visual perception of luminance decays exponentially, according to the strongest distinction.
- jmount 13y ago
  I think it may be more accurate to say perceptual description of luminance may be exponential (that humans report the difference from 1 to 1/2 as being the same as 1/2 to 1/4). But I think this is all irrelevant if you are trying to reproduce tones correctly (other than it says the error-model is relative error on tones). So I would say it takes a very labored reading to think of the article statement as correct (as light falls of 1/R^2 not exponentially). But that also makes the article's point: if you are painting what is there you are more immune to wrong assumptions.
  - maaku 13y ago
    Not necessarily. If you are making a painting, you don't have the ability to make some sections literally brighter (higher luminescence) because you don't really have control over the lighting conditions, and oil paints only give you so much ability to adjust reflectance. So what you do is subtly adjust things like tone, texture, detail or technique to 'trick' the human perceptual system into thinking the difference is there. These tricks are what imparts that life-like quality into the old master's works.
- jacobolus 13y ago
  The term “luminance” refers to a physical quantity, the intensity of the light. It can be measured in candelas/square meter. The relevant technical terms for the perceptual attributes of a color are “brightness” (which is the perception of how bright something is on an absolute scale given current adaptation of the eye/surroundings), and “lightness” (which is the perception of how bright something is relatively, taking into account knowledge of the scene lighting). Luminance (light intensity) is going to fall off with the square of distance. Brightness/lightness do not have an exponential relationship with luminance. The curve is (very) roughly like a square root. In any event, the article was clearly mistaken about this point. It’s a fairly trivial mistake though. Vanity Fair’s fact checkers probably didn’t bother to ask an optics / color expert about the statement.
jwmerrill 13y ago
Brightness decays exponentially for light traveling through smoke: https://en.wikipedia.org/wiki/Beer–Lambert_law https://en.wikipedia.org/wiki/Beer–Lambert_law. But I think the article author probably just messed up.
podperson 13y ago
No. But when journalism, art, and science intersect, expect casualties.

jere 13y ago

That was fascinating. I would have preferred some more details on the evidence found during this that a camera obscura actually was used. I suppose not having it makes this article a pretty good teaser for the documentary.

anonymousDan 13y ago
There's a wonderful book by David Hockney called "Secret knowledge: recovering the lost techniques of the Old masters" where he lays out some pretty compelling evidence for this idea. It's also beautifully designed, as you might expect from Hockney. I keep meaning to try out some of the techniques mentioned to see how well they work but haven't got round to it yet.
- podperson 13y ago
  The book is great and I'd say the case he makes is pretty water tight (and I say that as someone who wasn't much of a Hockney fan going in, and was very resistant to the idea that some of my favorite artists "cheated" ... but of course artists always "cheat" -- their goal is produce their artwork, not follow some arbitrary set of rules on how to get there).

shashashasha 13y ago

There's also this recent Kickstarter, the NeoLucida, that was all about remaking similar lens / optic devices artists and painters used in the past: http://www.kickstarter.com/projects/neolucida/neolucida-a-portable-camera-lucida-for-the-21st-ce http://www.kickstarter.com/projects/neolucida/neolucida-a-po...

fennecfoxen 13y ago
Less kickstarter-y webpage: http://neolucida.com/ http://neolucida.com/ I have one of these. It arrived recently; I haven't really tried it yet, but will soon. Wikipedia: http://en.wikipedia.org/wiki/Camera_lucida http://en.wikipedia.org/wiki/Camera_lucida -- it notes the basic optics were described in 1611 by Kepler.
pg 13y ago
I have an antique camera lucida, and it is startlingly effective.
- selmnoo 13y ago
  You use it to draw/paint? Can you please share something you've done? I'd very curious in seeing anything you've painted with it.

nathanallen 13y ago

> I’ve got a file of counterarguments to my own theory Thank you for having scientific integrity. Falsifiability for the win.

wrongc0ntinent 13y ago

Hockney's book is great, but for a quick and entertaining look at the theory, there was a (BBC I think) documentary with the same title. Probably on iPlayer and YouTube by now, covers more than just Vermeer (no links since I'm not sure about the copyright status.)

pbhjpbhj 13y ago

>"But no one understood exactly how such a device might actually have been used to paint masterpieces." // Seems a stretch. I vaguely recall seeing a documentary - perhaps many years ago, probably on the BBC - on Vermeer's "The Music Room" and how it was understood to be created using an optical system [camera obscura?]. They showed a replica being used to trace an image. Related http://www.math.nus.edu.sg/aslaksen/projects/MC-CL-Vermeer-abstract.pdf http://www.math.nus.edu.sg/aslaksen/projects/MC-CL-Vermeer-a... uses the assumption of the accuracy of the dimensions to establish two of Vermeer's painting were likely done in the same room.

simonh 13y ago
Thats close, but not exact. The difference is in the technique of using partial images of the subject overlayed over the painting image, to get the colours and overall colour and lighting gradients matched exactly, at a fidelity the unaided eye wouldn't be capable of. The trick of matching the patch so closely that the edge of the mirror disappears is the real secret. A straightforward over-painting projection of the whole subject wouldn't help with that.

CamperBob2 13y ago

Interesting article (if a bit clumsily written) but I don't understand why it's so controversial. It should be pretty easy to tell if a photorealistic painting was made with mechanical or optical aids. There will be small positional errors in the image either way -- places where the perspective is almost but not quite perfect. The magnitude and direction of the errors (and how they accumulate) will be very different compared to those in a freehand painting, and shouldn't be too hard to analyze.

wrongc0ntinent 13y ago
It's not that easy, for a few of reasons. One is the establishment (no better word for the mixture of subjectivity, entitlement, money, and fashion in the art world). Rewriting art history is frowned upon unless it makes the genius artist look like a greater genius artist. Applying a scientific method doesn't work there. Another reason proving this is hard is that some artists do have a great ability to reproduce reality (this was really the most common way to measure an artist's ability before photography came along), but the economy of an artist's technique may reproduce some aspects of reality exactly, while other aspects are just suggested or completely ignored, so you'd need complete consistency. One more reason is that simply seeing a camera obscura image or a similar 2d image may change an artist's technique, they may become aware of things they hadn't considered before (this was the case with linear perspective, look up Brunelleschi's experiment - though nothing as elaborate as a camera obscura). For a camera obscura projection, lighting conditions are very specific, that alone might shift an artist's (mental) focus from being 100% descriptive to being very vague about contours. Basically, you can't "unsee it". Dutch artists from Vermeer's era are perfect candidates to have used lenses, because they had the technology. If you can find undeniable proof anywhere, it's probably there. Really the more proof adds up, the more ridiculous the naysayers appear. Some natural selection would do this field some good.
- blah314 13y ago
  Thanks, in four paragraphs you gave me a whole new perspective on Hockney's book on this.

SilasX 13y ago

I have a hard time understanding the dilemma here. Could someone please break it down? What difference would it have made to use mirrors and lenses, and how would that have improved his paintings?

cma 13y ago
I think they are claiming his view would be split between a zoomed in portion of the screen and the canvas. He could then mix the color until it matched up so closely with the mirror that the line between the two seemed to fade out. I still don't really know what the setup would actually look like and how far zoomed in it was, etc.. You would think the article would have a diagram.
- deleted 13y ago
  [deleted]
- deleted 13y ago
  [deleted]
- dodecaphonic 13y ago
  Tim Jenison was interviewed by Leo Laporte on Triangulation (http://twit.tv/show/triangulation/118 http://twit.tv/show/triangulation/118). They start talking about it between minutes 35 and 36, and he describes the process in a little more detail, including magnification, distance from the canvas and so forth
egypturnash 13y ago
Artist here. Okay. Working out perspective by hand is hard. It's a lot of work, that takes a lot of arcane knowledge. So's doing a photorealistic painting of a thing. You have to look at the thing, consider a bunch of relationships of the particular feature you're interested in at this very moment, and transfer those relationships to your canvas. That's a pretty complicated set of habits and brain circuitry you have to build up over a period of years. Tracing an image is immensely easier. There's all the perspective, there's all the proportion relationships. There's all the colors. Right there in front of you. You can spend an hour or two essentially doing manual edge-detection, and then start filling in areas. There's still stuff to learn - how to mix the paint to get the colors you want, how to apply it to the canvas, stuff like that. And if you trace organic stuff too closely, it starts to look stiff and dead. But compared to the amount of skill you have to learn to draw this kind of stuff out of your head? It's nothing. I mean, hell. Take a photo, print it out. Tape it to a sunny window, tape another piece of paper over it, and trace it. Then take that same photo and try to draw a copy of it, without tracing. There will be a huge difference between the two drawings you just made. The one made without tracing will probably have taken a lot longer, and have many more bits erased and redrawn. A lot of modern artists have this weird thing going on with respect to tracing. It's the worst thing ever, they'll say. Tracing another person's work to learn from, or tracing off of a photo, they're different kinds of art crimes, but they're still art crimes. Leaping around learning to break a scene down in your head and reconstruct it from scratch - essentially building a wetware 3D modeller in your brain, really - is considered CHEATING by some people. So Hockney's book on Vermeer's work is essentially saying "dude Vermeer was totally a tracer". Which in many artist's eyes is like calling him Not An Artist. Artists get weird about what is Art and what is Not Art, it's this whole thing that's about as inexplicable to a layperson as a programmer's choice of text editor. By using mirrors and lenses to project an image onto his camera to trace, Vermeer only had to learn the basic painting technique stuff. If he did, if he traced all this stuff, then some people will start saying that his work is no longer Art. It's just Illustration. Which, in the eyes of people who care about this, means that it is a lower, less respectable thing. Now it's just a filter applied to an image, albiet manually instead of via Photoshop or whatever. The truth of the matter (IMHO) is that a lot of the people who will scream bloody murder when someone is tracing are amateurs. Real pros can and will project images and work over them, build reference models in the real world or in 3D programs, and do any damn thing they can to make the hard parts of their work easier, to get all those little details they'd never make up out of whole cloth. I am pretty sure I've repeated myself a couple times here, thanks to the tiny window HN allows to type in. But hopefully this helps. tl;dr: If Vermeer used these techniques then he's a dirty cheating TRACER and is thus not a REAL ARTIST in some people's eyes.

discreteevent 13y ago

On Caravaggio: http://www.webexhibits.org/hockneyoptics/post/grundy7.html http://www.webexhibits.org/hockneyoptics/post/grundy7.html

discreteevent 13y ago

On Caravaggio: http://www.webexhibits.org/hockneyoptics/post/grundy7.html http://www.webexhibits.org/hockneyoptics/post/grundy7.html

001sky 13y ago

The 2006 monograph by the british artist David Hockney (for anyone interested). Secret Knowledge: Rediscovering the Lost Techniques of the Old Masters[1] [1] ISBN-10: 0142005126> http://www.amazon.com/Secret-Knowledge-Expanded-Edition-Rediscovering/dp/0142005126 http://www.amazon.com/Secret-Knowledge-Expanded-Edition-Redi...

peter_l_downs 13y ago
This work is referenced many times in the article.