Tim’s Vermeer…from a painter’s point of view

June 21st, 2014

After I posted various reports about the documentary film Tim’s Vermeer, a few readers encouraged me to give a scholarly assessment of Jenison’s claim that Vermeer had used an optical device called a comparator mirror as an aid to his painting. Given my limited knowledge of the use of optics in seventeenth-century painting, I found it more appropriate to examine the issue from a technical viewpoint, since I am by profession a painter. The fact that I have studied Vermeer’s painting technique and attempted to emulate his manner for over 40 years, I hope, might give me a discreet edge over non-painters in evaluating if Jenison’s device is or is not compatible with what we know of Vermeer’s pictorial strategy and technical procedures.

Following some lively discussions with Mr. Jenison on the finer points of Vermeer’s painting procedures, I was able to meet him in Texas and experiment with the comparator mirror on the premises of a full-scale mockup of scene of Vermeer’s Music Lesson which Jenison had built in order to test his hypothesis by paintings his own Vermeer.

My first attempt to use the comparator mirror was frustrating. Not only was I unable to produce acceptable pencil outlines of a black and white photograph with which Jenison had used in his first experiments, I was utterly incapable of matching on paper any of the photograph’s tonal values. To use the comparator, at least as I was attempting to use it at the moment, one is constrained to work within an extremely small area of the drawing, along a thin edge where the image of the comparator mirror abuts on the drawing below and the two can be compared. Initially I found this procedure mentally and visually stressing, and at odds with my experience in conceiving and making paintings.

With a little more practice I was able to produce a few acceptable contours, even though they lacked any sort of artistic quality. However, seeing that I am not particularly skilled with a pencil, I though it best to test the device with paint and brush with which I have greater familiarity, even though on first consideration the oil painting technique seemed even more at odds with the mirror’s limitations than with dry drawing.

Surprisingly, I made rapid progress with the oil medium. Although with a certain fatigue, I learned to define first simple and then complex contours with a fine-tipped brush and began, even more surprisingly, to marvel at how it was possible to match with utmost precision both the chromatic and tonal values of my painting with those of the mirror in a completely objective manner.

Having made substantial progress in coordinating mind, eye, brush and mirror after a few painting sessions, I started afresh and began to depict a small portion of Jenison’s Vermeer mockup Vermeer room following what I have come to understand of Vermeer’s multi-step painting technique. Beginning with a schematic line drawing which served to fixed the most salient contours of the scene, I first underpainted the lights and darks with monochrome brown (raw umber plus black) and white paints without, however, systematically consulting the comparator mirror. I was, in fact, interested in testing how close I could get to the correct values on my own.

Once the underpainting was thoroughly dry, I began to apply the final colors over it using thick opaque paint in the lights and thinner paint in the shadows, according to seventeenth-century prescription. In order to render a given passage I first mixed, as all painters do, the proper paints on the palette attempting to match them as closely as possible to the color and tonal value combining what I perceived in nature with I had learned through practice. I then applied the mixture to the canvas and compared the values of my paint to those of the corresponding passage in the mirror. I sometimes discovered that both the color and tone of my mixture were very close to those seen in the mirror, but just as often I was struck by how poorly I had interpreted nature notwithstanding my decades of experience. In a back and forth manner I was able to register the erred values of my work with those of the mirror and return to painting. Once the proper values were firmly in place, I freehanded most of the modelling as I would have done without using an optical aid, taking care to verify the accuracy of my progress via the comparator mirror at regular intervals. The comparator mirror was also of help in verifying difficult contours and defining the smallest details that I had been unable to capture by freehand.

In any case, once I had registered the values of my painting with those of the mirror, the passage appeared much more true to life (painters simply say “right”).

Although the set of mirrors and lens (Jenison’s used a double convex lens of the camera obscura in coordination with a concave mirror and a comparator mirror) requires periodic adjustments in order to view the different areas of the scene, this does not unduly interrupt the painting process once one has acquired the necessary skill maneuver them.


Given Jenison’s complete lack of painting experience, he painted his Vermeer employing the comparator mirror, as would be expected, in the most literal of manners. He painstakingly matched what he saw in the mirror with paint applied directly, alla prima, forgoing any sort of layering techniques that we know Vermeer and his more accomplished colleagues sometimes employed. This aspect of Jenison’s approach provoked considerable criticism, including my own. It was reasoned that Vermeer could not have used the comparator mirror because Jenison’s essentially paint-by-numbers technique, and the consequential one-layer paint structure gotten by such an approach, is completely at odds with the multi-layered structure of Vermeer’s paintings.

According to my experience the comparator mirror neither dictates nor limits the painter to any fixed procedure or techniques, including those used by Vermeer. Certainly, it would interfere no more with the creative painting process than a systematic use of the camera obscura.

If it is used in a “painterly” manner, as any experienced painter would be naturally inclined to do, the comparator mirror opens the possibility to study color more precisely than can be done with the camera obscura alone and allows the artist to match with remarkable efficacy the illusive tonal values of nature, which in effect are crucial to Vermeer’s unique brand of realism. Furthermore, I discovered that the erred tonal values of my monochrome underpainting did not compromise the rendering of the proper tones and colors of the final paint layers. The aim of seventeenth-century underpainting, as I understand it, was not to establish the precise tonal values of the final work from the very beginning, but rather to approximate the distribution of darks and lights thereby creating a sort of compositional blueprint which provided a solid base on to which the successive layers of colored paint could be applied in a more efficient manner. Although I used the glazing technique in only one passage (red madder over an underpainting of vermillion), it was evident that with some practice it would be relatively easy for any practiced painter to anticipate the tonal and chromatic values of the colored underpainting so they might eventually match those made visible in the mirror once the passage had been glazed with the final color.

The use of such a simple device as the comparator mirror in tandem with the camera obscura lens, in my opinion, is technically compatible with Vermeer’s known painting techniques (to be distinguished from his “pointillist” mannerism), and it is in line with what Lawrence Gowing appropriately called the artist’s “optical way” as well as the artist’s search for absolute tonal authenticity.

555 Responses to “Tim’s Vermeer…from a painter’s point of view”

  1. dave

    hi jonathan – first off, i love the site! thanks, it’s a great resource.

    this thread on tim’s vemeer is great but what happened to the images of the test paintings you did of the setup?

    why’d you take them down and have you done anything at MONA yet? can’t wait to see the results of yours and anyone else who tries it.



  2. Germán Vicencio L.

    I have an observation for the author of this article, Jonathan Janson.

    In your article, you say: “He [Tim] matched what he saw in the mirror with paint applied directly, alla prima, forgoing any sort of layering techniques (…)”

    But after watching the movie/documentary, I can see that your statement is not 100% true. For example, when Tim paints the rug we can clearly see that there is a first layer in which the shape of the rug is well represented without details (like if it was a “soft rug” or “draped”). This also happens in other parts of the painting.

  3. Lady_Fenir

    Consider frist surface mirrors that could have been in use in 1600s. Also test how a silver mirror would have altered the luster. It is very likely you may get better results with a frist surface mirror, as the abrasion of the glass is not a problem. Also perhaps silver could be connected with the ethereal luster i see in Vermeers. If there where lenses then modren arcomatic glass was not in use, nor was modren vapor doped glass. I believe leaded glass was the clearest in that erra, a rarity in our time.

  4. Dr. David G. Stork

    One of the features of some of Vermeer’s works that suggests the artist used of some form of optical projector are the blur spots (circles of confusion, which have been described as “globules of light”). These resemble the blur spots in an out-of-focus projection onto a screen. Tim’s optical setup and mirror comparator would not yield such blur spots because the artist would accommodate (refocus his eyes) accordingly, just as we do during natural vision. Alternatively, if you argue that Vermeer would *not* accommodate (thereby leading to blur spots), then we should see profound and very obvious effects of depth of field (blurring as a function of an object’s distance from the “conjugate” distance where the system is focused).

    In short: what is the mirror-comparator explanation and evidence (if any) for the “optics-like” blur spots in several Vermeer paintings?

  5. Dr. David G. Stork

    I just viewed a YouTube lecture by Philip Steadman concerning Tim Jenison’s work in which Steadman said (more than once) that Jenison’s apparatus was “simple.”

    My view is the opposite. Had Vermeer invented and built (and kept secret from his contemporaries) the device used by Jenison, it would have been the most complicated optical device on the planet at that time. As far as I can tell, no optical device documented from that time would have been as complicated or subtle, in the following manners: The proposed device…

    • had more optical elements than any known device (three)
    • had more TYPES of elements than any known device (three… converging lens, concave mirror, plane mirror)
    • had the most precise alignment requirements (by far!) than any known device
    • involved a complex (and extremely tedious) procedure

    The proposed device is far more complicated than Hans Lippershey’s revolutionary telescope, which had only two elements of the same type, and where alignment was guaranteed by a tube. (The proposed device has very precise requirements in both separation along the optical axis AND orientations.) Closer to Vermeer: the proposed device would have been far more complicated than the single concave mirror that Gerrit Dou may have used as a primitive telescope for seeing details. As far as I am aware, there is nothing in Ibn al-Haitham, or Roger Bacon, or indeed any of the world’s leading optical scientists that even approached the complexity of Tim’s device. Moreover, the proposed device, as designed, has numerous wheels and adjustments for elevation of the lens, of the concave mirror and of the plane mirror. The device is far more complex than William Hyde Wollaston’s camera lucida, invented in the 19th century. The greatest scientist in the history of the world, Isaac Newton, invented a telescope with mirror “injector” AFTER the execution of Vermeer’s “The music lesson.” The greatest telescope designer of that 17th century, Laurent Cassegrain, invented his TWO-element mirror telescope AFTER the execution of “The music lesson.”

    It simply will not “do” to say that because the device is simple by 21st-century standards–actually Tim showed conclusively that it is NOT simple, even by 21st-century standards–that it would have been “simple” in the 17th.

    It seems to me the only two acceptable responses to these points are:

    • Documentary and (if possible) material culture or other strong evidence of an optical system from the date of execution of “The music lesson” (or earlier) that is more complicated than the proposed device.
    • An acknowledgement that the proposed device would indeed have been the world’s most complicated optical system of its time–their “Hubble telescope.” Further, that you are arguing that someone for whom we have little or no clear ancillary evidence knew optics invented the world’s most complicated optical system of his day, before Isaac Newton invented a device of lesser (but comparable) complexity. (And stop telling the general public that Tim’s device is “simple.”)

    If the response is the first, then you will have made significant contributions to the history of optics (and possibly art history).

    If the response is the second, it will allow independent scholars to better judge the plausibility of the mirror-comparator claims.

    –David G. Stork
    Fellow, Optical Society of America

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