The Ansel Adams Zone System - Hdr capture and range compression by chemical processing

MCCANN: ...of fabulous pictures first time you ever held a camera. And then another, and then another. I'm just making--make sure I'm not going to disappear here. Okay, we're in the business. And that was the spot where I thought he might want to take a picture and says, "No, I don’t see anything there." And I went back, took several more. And I just felt like a complete clod. I felt I was, you know, walking through--going through a garden, but I was stepping on all of the flowers. I just missed all the good photographs. His visual command was just extraordinary. They--okay, that all seems to be working. When we look at images in today's world, we usually think of Photoshop. We think of Photoshop as a sort of a new thing because you can take any pixel and make into any other value that you like. And you can characterize the scene by the histogram there. I guess I can see a little bit clearer back there than you can here. And the total scale curve is probably the most valuable feature that lets you transform the image you have into the image you want. And so, here, we're talking about digits in and grayscale value out. But in fact, it's a very similar curve to the original Hurter and Driffield, H&D curve that photographers talked about and certainly are very familiar to the zone system. Okay, there we go. If you compare film and digital photography, in fact, they're quite similar, although the techniques are a little bit different. We have a lens, a camera, a sensor, sensor processing, restore it, one case in a negative, another case in a digital file. We read it. We anticipate what we want to do with the image and we display it. Now the tools in the optics are pretty similar except the size constraints are a little bit different. It's the aperture of the number of elements, the coding, the resolution, the volume of the camera, and the surface of the sensor; it determines a lot of different things. And John had invited me two years ago to discuss some work we've been doing in measuring how much information you can capture in high dynamic range imaging. Today's popular technique is you take a series of exposures and out of those many exposures, merge it into the image you'd like to have. Now, in fact, if you look at the data very carefully, you find that all these nasty things like number of elements, and codings, and apertures, and surface reflection; namely: glare. Glare provides a serious limit to what you can capture on the film play. The multiple exposures you take do not give you information about the scene. They give you information about the scene plus the veiling glare, the unwanted stuff that happens in the camera. And so, it turns out what you have on that image plane is a function of not only the scene but the features of the camera. So, HDR imaging is not an accurate rendition of the scene but it provides more useful information. Although it just doesn’t happen to be the real accurate information. So you take--and that’s the same for both whether you're on a digital camera or a film camera. The techniques--and so the highlight or you put it in the--you go into the dark room, you put it in a developer, you stop the development with acidic path, you put it in hypo to get rid of undeveloped silver, you wash it, you tone it to change the--I see you change the surface properties of the silver to get a better covering power, and then you wash it again, and you dry it, and you have a finished negative. In digital imaging, you have an A-to-D converter. You have something that does noise reduction. You transfer that signal to a digital part of the system where you do the de-mosaic-ining, the sharpening, the image enhancement, and then you compress it. Now on the printing side, you can use different types of enlargers which in fact affect the essentials of response function, and the grades and the surface and the whatever. So, what I hope to do in this talk is to compare this, probably, for most people your age, unfamiliar things, because you probably haven't spent much time in the dark room, with a wonderful techniques we use in digital imaging. And just, by the way, Ansel was my coach in black and white chemical photography and John Franklin here was my coach in digital photography. At 19--what was it, '72, you started to set up a digital image processing lab at Polaroid which was far ahead of most other labs that started to do image processing for photography. Ansel divided making a print into three very important steps. First of all was the visualization. For Ansel, you had to have an idea of what the picture was supposed to do before you took the picture. It wasn’t the occasional, "Let's grab something and then refine it later." It was--the negative should be very carefully composed, exposed, and developed. In fact, Ansel went to the trouble of changing the characteristic--anticipating what the film should do and exposing with the type of development he was going to do in mind. And I'll talk about that more later, but you wanted to visualize for what it was. The second step was to capture all the usable information and he often described that as the musical score. He was at his young man, he was trained as a concert pianist and he was both a photographer and a pianist, and he found it difficult to spend the time for doing both and he decided to become a photographer. It's quite common to think of a pianist to spend hours per day just practicing. Ansel took that framework and did it with his photography. He practiced taking pictures more than anybody I ever met. Most of us grab the camera, go take the picture. Well, Ansel would never do that. He would take the camera. He would try this setting, that setting. He would continually learn how to do these things. And he was an absolute master of capturing the musical score. And in fact, what he was doing, we would say today--we would say, well, he was controlling the tone scale of a sensor. Then he would render, you'd call that the performance. And there's two parts of that. First, is you want to scale, you want to get the best tone scale, a response from the media you're going to, the printer or the display, or whatever. But also, in many cases, because the dynamic range of the print is very limited, he manipulated using a kind of spatial processing. This was essentially dodging and burning, moving his hands around to make an image that fit his visualization. And that's really the essence of the talk. Now, in fact, just yesterday, there was a symposium at the electronic imaging meeting in San Jose. The keynote speaker there was John Sexton, longtime friend, colleague, co-worker of Ansel's. And I just wanted to let you know to put on your calendar; John's going to be speaking in the Adobe Distinguished Lecture Series. I think it's going to be June 15th. But--you'll find it on the Adobe website. And he just gave an absolutely marvelous keynote address where he talked about Ansel's images, how Ansel made the images, how do old movies of Ansel climbing to, actually climbing to take these pictures here, and with music accompaniment by Ansel playing the piano. So if you're an Ansel Adam's fan, look up John Sexton on Adobe Distinguished visual. He's coming to an auditorium near you soon. Ansel regarded this picture taken in 1927, that’s in Yosemite Valley. He and his wife and three friends climbed halfway up. He climbed up to this, they call a diving board. It's about halfway up to the top of--they brought up picnics, they were all photographers. They took pictures. Virginia, his fiancée, later his wife, the lifelong wife, was--went with him and took movies and you'll see him in John's talk. Ansel took these pictures with a 6x8 view camera. He brought up glass negatives. And the reason they were glass was that, essentially this was even before you could get panchromatic emulsions on nitrate-base. There wasn’t a safety film base that we used today. This was only old very unstable nitrate base material that they used in that time, but you couldn’t even get that. There had to be a glass plate if you wanted panchromatic emulsions, which means sensitive to red light. Ansel took the picture on the left with a yellow filter and then he visualized. You see--he didn’t--there were no digital displays to see the image that you just took. He started to think in his mind what's that going to look like? "Well, I'm going to have a gray sky and it's going to be next to a gray monolith." And he had such familiarity with his tools that he said, "Oh, I'm not going to like that picture." But the sky is going to distract from the impact of the half dome of the monolith. So, he then--in those days, he reported to John there were no accurate light meters so it was his photographic experience that told him how to expose the negative. And he had practiced enough so he knew that with a dark red filter you needed two and a half stops more exposure. So he adjusted the exposure, took the picture with a red filter which rendered a black sky which left the vision of--his vision of the monolith become apparent. And he often told me that he was so excited when he took that picture. He ran down the hill. You'll see it in the movies. It's a 45 degree climb. And he immediately went to the dark room and made the print and it was--he'd often described that it changed his life because he now knew that he could manipulate things to do the things we all know we can do in Photoshop. An HDR or my favorite paper is a paper by Jones and Condit from Kodak. It’s a paper that measures a great number of scenes, 126 outdoor scenes, and measures the dynamic range. And this is mainly to illustrate that the world that have a 3.0 log unit range, most of the scenes that they took that they thought would be average people pictures would be 2.2 log units. But in the print you have right around a hundred to one. You don’t have--you have a natural smaller range in the print than you do in the worlds. So how do you take this great big world, this wide dynamic range of stimuli, and put it in a low range media. In fact, this is what the color negative film. If you think in the last half of the previous centuries, there are probably a trillion prints made from a Kodak negatives or Fuji negatives or--and essentially, that is a technique where it compresses the highlights and the shadows and it in fact expands the midtones. If you take an Ansel Adams print, make sure you're not measuring any glare from the glass or the surface of the print. You get a 0.15 candelas per meter squared from the rich black sky and from the white bright clouds, you get 17. That’s a ratio of 114 to 1 is the range of the print can deliver. Now these blacks and these whites are amongst whitest and blackest you will find in photographs. They are very skillfully done. They're selenium tones so that the densities here are deeper than most materials, and Ansel was a great craftsman so that there was always minimum density in the whites. So how do you fit this into the world? Well, what you do is you can't do what we say a CCD does. A CCD counts for tones and you have a nice simple linear relationship that run the amount of light caught and the value coming out. The fellow who was a director of research at Kodak for 50 years, a guy by the name of Mees; and in fact Mees was one of the few--I worked a lot with, Edwin Land for--at Polaroid. And there are some people you always knew he had a great respect for. He would just almost change his tone of voice. And he would always refer to, just to me, as just the great director of research at Kodak, because essentially, he started off at the University College London. He repeated Hurter and Driffield's experiments. And namely, he measured the sense of trimetric response of films. He invented the tone scale in his book in 1920. He described, here, you have two tones, and here you have three tones when you add a shadow and four tones if you add that fade shadow. And so he was describing the response of a film as a tone scale. Now that fit very well with the--Kodak sort of had a policy. And around 1900, they introduced the Brownie camera and the idea was, "We'll, you take the picture, we'll do the rest." And it was quite an organized and big thing because in fact, there was a newspaper ad in just about every paper in the United States all at the same time by 1901 or 1900 or something like that. So that was a pretty big organization. No Google ad where you could do it at one email. You have to write all those letters to get that many people to do it. Well, Kodak had a policy that they really wanted to get away from the complex jargon and all the secret formulas of a previous century of photography. And so they wouldn’t let him talk about H&D curves. He had invented a new synonym for sensitivity response function and that’s tone scale. And tone scale is something we use, continue to use today. Here is Ansel Adams' zones which are very similar. And you can see the--he tells you that this white reflected roof is zone nine. And this was the middle gray, zone five. And this is a black, zone one. So each of these were characterized, they're one stop apart. And as soon as he could use spot pathometers, he measured these areas so he could determine the range of the scene. And if he knew the range of the scene, he knew whether he should plan to compress in the development or expand in the development. To do that is relatively simple. Here's a set of zones with normal development for that negative. If you decrease the amount of development, you'd essentially lower the contrast, you'd lower the slope of the curve, you'd get to a wider range response. You'd get a still lighter range response if you decrease it even more. Oppositely, if you extended the time on the developer and if you have a sharp dynamic range scene and you wanted to make that punchier, you would increase the development time. The jargon I learned before meeting Ansel was always, you know, "overexpose and under-development." And Ansel will always say, "No, that isn't right. You're going to increase or decrease. You know what you're doing so, it's not over or under, you know what you're doing." Today, we just think of it as, well, more development gives you a tone scale curve that looks like this, less development gives you like this but you could do this in a digital sense. You could set the quantization of the camera before you take the picture to optimize it for the scene. But that doesn’t fit the current attitude towards photography. Nobody in fact would even think of that. But it's quite a remarkable thing to be so careful and thoughtful about what you're doing. This is kind of interesting because if you take a simple linear representation of amount of light between a 100 and 0 and put it into equal steps, you got a grayscale or a zone scale or a tone scale that isn't very well spaced. You overemphasized the whites if you have a linear display of the range of information available. And that’s why photographers always used log because that gives you a better representation. It means the middle gray is not 50 percent reflectance; it's 18 percent reflectance. And in fact more recently, people have started to use lightness which is a cube root function instead of a logarithmic function. It better accommodates the fact that you get scatter in your eye and so these are equal steps in appearance if you use the cube root. So, these are all now logarithmic representation or rather these are exponential and that these are each factor of two more light than the other along the horizontal axis. These are optical density. So that’s log luminance, or log light, transmitted through the negative. So this is the effective development. That means two times the normal time in the development, or one unit, there wasn't [INDISTINCT] two times, but more or less development. These are the similar kind of responses you get from changing the grade of the paper. Now, these--all these graphs, in fact, were made by John Sexton in the second edition of a set of books that Ansel wrote. And I'll show you the titles and references at the end of the talk. They're still available today. They're fantastic books. But these are all just taken from Ansel's book, The Negative. So, let me just go through it. Here's the paper grade. The manufactures would sell you different contrast papers so that you could make your negative look more contrast to you or less contrast to you. And as you can see as you increase the rate of change you would decrease the range. So those are two are always linked together. Just about now, everybody uses a spectral film so you'd use a slightly different colored filter on the same piece of paper and that would change the slope just like changing the paper. In the old days, you had to stock three or four different kinds of paper to make the print. This is again the Ansel's example. If this is the range of the negative and the positive print on grade one would give you this long low slope low contrast image. But on grade three, you would take and make that higher than the normal print. If you change your brand of developer or your concentration of the level, you'd similarly get a curve like that. The emergence time factor is also an interesting thing. You're working with a chemical that reacts and so that it is consumed. So if you're making 20 prints, the 20th print will be lower in contrast than the first print because your concentration of active ingredients has decreased substantially. It's been used up by the previous 19 prints. So Ansel had a very ingenious system. When you're sitting in a dark room you have a safe line. That would be a far red light or a yellow light. And you can see the print, you can't see it well, but you can see the print. So he would time, the length of time from when he put it in the tray to when he saw a particular object emerge. And so that might be 10 seconds in the first processing. And then he had a factor figure. If it was factor 10 that means I will take it out of a 100 seconds. And so, if--now, in the next print, it might take 11 seconds, well, you take it out on 110 seconds. So, he multiplied the time of emergence by the factor. And so by doing that, you can see here over here, he has plotted diluted negative, the diluted developer solution. Using this technique can overcome the effect of the diluted development. He can get a constant result out from a chemical bath that was changing uncontrollably. We've already talked about development time. And the enlarger, it depends upon whether you've got collimated light or diffused light. And the selenium toning is a very interesting thing. If you process the developed silver with these selenium salts, it actually changes the surface property of the silver and gives you a blacker black. And Ansel was an absolute master of that. You can also go wrong if you would put the right--you can get the black silver to change color if you file that up. Well, what's beyond the tone scale? This is important but what I think makes Ansel's work spectacular is the things he did beyond the tone scale, the dodging and burning. The best example of that is an experiment that happened a little bit before John joined our lab. It was an experiment by Edwin Land called the black and white Mondrian; because in this experiment, he had a bright light near a dark gray object and the illumination fell off with distance. So it was a very dim light up on a white object. And my job was to keep moving the light around till the same amount of light came from the white area at the top and the black area at the bottom. Now, if you take and think of that as digits, you take a photograph of that, well, that’s the same--that could be the same digit in the camera here as here. If you manipulate that with a tone scale, what you'd like to do to make this print better is you'd like to make this lighter and this blacker. But, you see, I got a problem with it. I got the same digit. No matter what I do to the tone scale, I can't make the same digit go up and down at the same time. I can't--I can make this lighter but then this gets lighter. I make this darker but then this gets darker. You have to do something different here then here to improve this image, and Land did this. This is an experiment about the visual system to show that humans don’t count what you see. It doesn’t depend upon the quantum that happens to follow on the receptors, it happens on the relationship between the other areas in the field. Sorry. If you scan, I've rotated the picture here, so that is the dark area and there's the light area. You can see I've scanned the digits along this path. You can see, well, we start off here and then we have an edge and then we have another edge. In between, we have a gradient. If you study this, you'd find, well, let's just look at this little patch of one of these Mondrians. If you look across this edge, you see it's a 160 to 240 and you'll see a little bit better here. You have a highly visible edge. If you look here, you can see that--well, from here up to here, it also changes to 160. So we have the same change in the amount of light. However, one is very visible, namely the edge; and the other, the gradient, is highly invisible. So if you--you can do--another way of saying that is you can do anything you want to these gradients because you can't see it. You can make this go down and it'll look virtually the same as having it go up. However, if you change the size of this edge, you'll see it. It'll be a big change in appearance. All of this comes from the fact that if you like to think--I always used to like to think about, "Well, what's important is the amount of light coming from--that’s a 100, and that’s 20, and that’s 50." That’s why you see it as, you know, white-gray and darker gray. But in fact it's not, it's the relationship. And so if you keep track of the relationships, you can do anything you want with the gradients. And so, vision allows you to do things to an image that can improve it. It can help you compress it from that great big world into that tiny print. But you have to be careful the way you do it. Another way of thinking about it is that in ordinary films you have a specific amount of light. And that turns into to a specific response of the film, a specific density. And that’s true of all the pixels in the field of view. But if you study human vision, a particular amount of light, well, it can be a white, it can be a gray, it can be a black, it can be anything you want depending upon what you do to the other pixels in the field of view. And so, that’s why if you manipulate these gradients you can change the appearances. And in fact, this is a project that John worked on. In fact, this is one of John's patents. Ordinary photographs--I show this because it was taken at one of Ansel's workshops. And here's a polar--a set a Polaroid prints of overexposure and normal underexposure, and the same amount of light is coming from this white area in the shade as this black area in the sun. Now, this image was taken on a Kodak negative which was about a 4.0 log unit range. They scanned it. They brought it back to the lab. They processed it by using spatial manipulation and we're able to render this picture so these are no longer equal in the print, we've compressed the range of the print. If we just took and squashed it by linearly compressing everything, this would look like a foggy day. But if you spatially manipulate the image, we're trying to do what Ansel had taught us. You can maintain the edges and change the gradients so you don't see it. And in fact, these are some other images that are processed using these techniques. This is a private picture taken by Bob Sobol of HP. And in fact Bob was instrumental. HP used to have a camera that had this processing in it. Unfortunately, HP doesn't like cameras anymore. It did not cost of that. It didn’t save anything. But this is all about Ansel and so here's Ansel making a print, the so-called dodging and burning. Here, he's burning the top of an image. He's giving this more light so as to bring out the detail in a part of the image. Here, he's dodging. I don't know if you can see it. But if you put your hand here and cast a shadow from the light, you have a sharp edge and you can see it. But if you further away, I have to get on a chair to demonstrate it properly, you will have an outer focus image. And if you move it onto the film, you can create a very soft change in illumination. That's so-called dodging. You take essentially a lollipop and you withhold film from a part of the image. Ansel also had a mechanical way of doing this. This is his enlarger with rows of lights. So if he wanted to create a non-uniformed control repeatable illumination, he would just turn on and turn off these lights to have a light mask to hit the negative to control what the print look like. He preferred to do the dodging and burning. John describes it as Ansel dancing in front of the film. So to make a print, what Ansel would do is here's one of his famous--these again are taken from Ansel's book, The Print. You make a series of exposures by just moving a card across the light. So you'd start at here at the--you would start here and expose this area and then take the card away and expose this and then this and then this and then this. So then that would tell you the exposure and it'll tell you the grade of the paper that you wanted. But when you look at this print, I think you can see that there's not much detail in the sky. There's a little bit more than around that screen but this sky is very weak and, well, it's the right exposure for the lower areas. To make--to see the details that are in the negative in the sky, you give it extra light. So there's Ansel holding the card preventing light from coming from the bottom of the picture. Here's an example of dodging. And here this is the straight print. And Ansel didn't like the tonal relationship between these pines and the other trees. This is an example of dodging it poorly. He's withheld too much light intentionally and you can see that the other trees have this white halo around it because the gradients were changed to severely. But this is what he wanted. He wanted this relationship, this lightness versus this lightness for these particular images, these particular trees. And in fact, he had a formula, a prescription. A recipe I think they call it for each and every different print. This would tell you its print over the 24-inch lens. This was the time as calculated from the metronome; he didn't have a timer he used a metronome to count it. There was an F22 select all and deck tool, the time was the concentration. There was on a paper called Seagull and it was toned in selenium and the factor, it was eight times after he saw a particular feature involved. And then he would withhold the exposure for two seconds, I guess, I don't know, for some factor, and then he would give extra exposure here, extra exposure here, more exposure there, a lot more exposure there, more exposure there, and do it with the whole. So he'd do all of these steps and this would be the resulting image. So the print you see is not Ansel capturing the real world as it is, the print is Ansel capturing all the information possible and then rendering it to fit his aesthetic content, to fit his visualization of the emotion that he wanted you to see from that image. So here we have, we have a straight print; and dodging and burning turns it into this print. What Ansel is doing is changing the gradients while preserving the edges. And this is one of John Sexton's prints using the same techniques. There is the negative. This is from, Listen to the Trees; a really fabulous book. This is the straight print. If you don't give the straight exposure, just do the dodging and burning. You are adding this to this to get this, the rendition you intended to do. Now, the--this is an example that I think is probably one of the simplest but in fact a very profound thing. If you--on a Polaroid a film, you were completely unable to change anything. The film manufacturers, the factory decided what it is that your film is going to respond to the light of the scene. But that didn't stop Ansel. He developed this technique of pre-exposure. I don't know if he developed himself. He knew what the process and he thought all of us about it. Is that if you take a picture and you find, you've lost all of the information you like to capture, you would pre-expose, you would take a uniform card to hold it in front of the lens, cover the field of view, have uniform light on it, turn the aperture way down and essentially give a--sometimes called a bump exposure, an exposure to take from and expose all the gradients at the threshold of detection. Then when you take the photograph, so you take those photographs then take you these photographs, in fact the pre-exposure plus the scene give you a better dynamic range. You can see more information in the print by having raised essentially a fog level everywhere. So you have this great irony. You have--you've decreased the actual physical dynamic range. No question about the light. You have increased the apparent dynamic range. So what have you done? You brought out some edges that were sub-threshold. You've changed the shape of the curve by exposure as opposed to the way he liked to do it with development. So it's a very simple lesson but it has profound implication that tells you a lot; capturing all those bits and reprocess them in meticulously rise and keeping them in dynamic range. Well, that's a good thing to do but it's not a necessary thing to do. It's not the crucial thing in getting the rendition that you would like to have. So just sort of summarize this; Ansel was an absolute master at spatial rendering. He would capture the high dynamic range information, capture all of it if possible. He would then synthesize a new image. He would preserve the spatial ratios. He would distort the input luminances. It's not an accurate record. He would decrease the actual dynamic range, but he would increase the apparent dynamic range. Now all of these things we can do with automatic image processing because we can preserve the edges and we can preserve the dynamic range. But we can't do it automatic in image processing is due--is at the static content, is at the power associated with the, you know, the emotionary reaction you'd get when you look at these pictures. At least, I don't know anybody who can do that. But maybe that's something that we should worry about. These are the books that the--now, there's a lot of stuff about deck tile that I probably can interest you in. And though Ansel--though, John Sexton said in his talk yesterday, it was kind of interesting. If you can find somebody who's still has a dark room and still goes into the room and slashes things around, just ask him to come see it because they love to show you, they won't even charge you. They love it to do it so much they'd love to show you. And it is really worth seeing. It is an experience that is about to become extinct. So grab it when you have a chance. But these books have profound information about everything and everything to do with photography. And there's a lot about deck tile that you can just forget about it and just skip over it. But they are great books that tell you a lot of stories about imaging. And then if you're not interested in the technical details, the last book, they are the examples of how Ansel made [INDISTINCT] of these most famous photographs. It's a wonderful read. It's a wonderful bit of history. It is really worthwhile. These books are still available in bookstores but, of course, you could google it and you'll find all the additions from all of the different places. And these are just a photograph of who we were going out with a 20x24 camera to make some pictures. And this is my friend, Pyhllis Diller, they just gave me this photograph as a remembrance of old times. And so this is the married man that worked on 20x24 photography at Boeing. So thank you very much. I'll be eager to ask or answer any questions you might like to ask. And do remember that to look for John Sexton's topic at the door. >> Since you mentioned 20x24, I just recently learned about the 20x24 [INDISTINCT]. >> MCCANN: The question is am I familiar with the Polaroid 20x24 camera. Did John pay you to ask that question? >> No, no, no. >> MCCANN: It was kind of a long story but Polaroid had made an 8x10 system and there was a tradition that Land would always go and give these very dramatic shareholder meetings and 3,000 people would come to a shareholder's meeting, not to hear the financial results but to see Land's demonstrations. And Land had a policy, it never stopped working on a shareholders meeting more than four weeks before the meeting because everybody allowed to jump in and help out and he would just blow everybody's budget. So his economic--his budgeting feature was limit the time people could do things. And so, it was always some demonstration of something that was not going to be a product, it was going to be a gee ***. So, I had the job of being in charge of the research machine shop and so he called me up and said, "I've just seen this 8x10, but with 3,000 people it’s not big enough. Can you make a 20x24 camera? Get there to make it 20x24 camera and we’ll make it just like the original camera that we demonstrated the instant photography of the Optical Society meeting in 1949." So we went to work. We didn't even know that 20x24 film wasn't 20x24, there's a margin inside, but we’ve made it 20x24, so we made it the wrong size. A week later I came back and told Land, "Well, we've got this machine shop making that, we got the rolls underway, we have found the lens, we've got the bells." It looks like and, well, also he asked us five weeks ahead of the meeting, so I knew that that was kind of dangerous. At four weeks he said, "Well, what I really want is a camera that will photograph [INDISTINCT]. I looked that up, it's 39 inches wide. Can you make us a camera that's one meter wide by two meters high? And I said, "Well, you know, we got our four weeks, how can I say no?" And so, we pulled it off. And in fact, at that shareholders meeting, Yosef Karsh took a picture of Ansel Adams, a portrait of Ansel Adams, and we showed that it doesn’t pick pictures from them, plus the Museum of Fine Arts that we're photographed on this [INDISTINCT] imaging. So, yes, I do know. I said a bunch of questions. >> Okay, so my other question is, or that sort of explains why--I was amazed at a [INDISTINCT] I've seen video demonstration where you pull the negative down by taking a string, double tape it. >> MCCANN: Yeah. >> And tape it to the negative and pull it down. You adjust the camera but you can [INDISTINCT]... >> MCCANN: Right. >> ...the keys to the camera? >> MCCANN: Well, the fact that camera is still going and the reason its going is because of that. That adjustment is what was in the original demonstration of the Optical Society. That adjustment is moving the rollers back and forth to control the thickness of the developer, and that's the key thing to getting a good picture. In fact, those rolls are--have a can burn. They are not flat, they're milled. So they were crowning them so that to get uniform developer across the width of the sheet you have to have the rolls tighter in the middle and on the outside. Ordinary film they're passed--there are papers things to set that gap but that is a real bear if we're going to manufacture film because, in fact, what we were doing is we were ironing them on in the first version. And Ansel said, "No, no, don’t do that. Just set the gap and you’d get to rid of that whole manufacturing stuff." So, all you put in to the camera was raw negative, raw positive, there was no film assembly, so. And it is still going. Somebody has bought all the available negative. You can get Elsa Dorfman to take your picture in Cambridge, Massachusetts. The--it's still going even though the Polaroid, this is--I think it, I don’t think there's any other film made by Polaroid that still exists at the moment, and--except the 20x24. So, that rig he did--and they were five that were eventually made. And they have just done a lot of incredible things with a lot of incredible people who used it. But, I can tell you the infinite number of stories, I'm all a part of everybody elses. Yes? >> As I understand it, when Ansel Adams was exposing negative into the very technical processes. Careful measurement of [INDISTINCT] in just the exposure development symptoms. >> MCCANN: Yeah. >> You’re shown some example of a good [INDISTINCT]. A good trial and error stripped of the exposures. Have you been able developed any technical way of quick way we may extent of [INDISTINCT] or it's just trial and error that it might be? >> MCCANN: Well, the whole first half of... >> [INDISTINCT]. >> MCCANN: Oh, thank you. Christian is in. I've described sort of a two sides of Ansel Adams. One, a very technical, mechanical side into the less--the guarding and burning is more very--apparently, more variable and was there a more definitive technical repeatable process that he developed. And I don’t know. I don’t know if I just described that well. I don’t think I did do the job. Everything in the exposure and development process was very meticulously controlled just like the times in the past. The dodging and burning, he did quite precisely. Again, this pianist training, he could make 20 prints in a day and they--you couldn’t tell the difference. I couldn’t tell the difference, maybe he could. He had techniques such as the switches on the back of the enlarger to do that kind of thing. So he certainly tried them but he preferred doing it that way because he thought he would have better control. He was just incredibly good at it. In fact, any print do you see that had Ansel Adams signed, he himself did all the printing. He printed it. He might have had people help him dry it or spot the negative, spot the positives, or whatever it is. But he crafted all of his pictures. There are pictures that are A.A. signed and those were pictures printed by Alan Ross, his close associate, all done in Ansel's home under Ansel's supervision. So now, you will see different renditions but that's because Ansel changed how he'd liked to print over the years. But Ansel explode all this things but I don’t think he found a mechanical means. Now certainly, in digital technology he could have found the solution. Somebody asked me in, after my talk yesterday, "Did Ansel Adams take any pictures in color?" In fact there's a book published of his colored pictures and many of them are really quite lovely. Ansel is now quite comfortable with color because he never felt he--the problem was that whole tone scale, the whole response of the film was made in the factory. So he couldn't get his hands on controlling that, to render the scene the way he want it so he was never happy with the manufactured tone scale, he wanted to make his own. Yes? >> Yeah. I'm just wondering, on the [INDISTINCT] realistic? >> MCCANN: Well. >> Do you think that's more realistic [INDISTINCT]? >> MCCANN: That question is the--as time goes on, we are increasing our ability to capture more information and display more information. And I have to argue a bit that in the talk that I gave two years ago which you'll find on your Google, I describe experiments where it measures the range that's possible to capture on the film play. And in fact I was unable to find in the camera's I tested, and it was not a comprehensive test, but the cameras I happen to test, the highest dynamic range came from a color film negative. And it probably had to do with the camera because it's a larger camera and it had less scatter than it was the digital cameras I chose. And you probably could reverse that. You probably could find a digital camera that responds better than the negative film. But for most images they're in a comparable range. And that’s because you got to separate the sensors. There was a recent conference at Stanford and one of the fellows there gave a talk about how good the sensors are getting. And he reported that he could get, I think it was 10th to the 11th, one part in 10th to the 11th in his sensor as a readable difference. I have no problem with that. The sensors, digital sensors, can do a phenomenal job. The problem is the optics have undesired stray light and you can’t get that to the image plane. You can’t get 10 of the 12th and your changing exposure just doesn't help because all it does is move the value up and down the tone scale but it doesn't change the ratio of unwanted light from the lens to a wanted light. >> I mean, did Adams [INDISTINCT]. >> MCCANN: No, right. Right. Right. >> I mean seemly... >> MCCANN: You, no, no. You certainly can improve in that direction. In terms of the digital display, it's also interesting because, for example, so the bright side image has a high resolution LCD and a lower resolution LED. So in fact, they are doing a very complex transform of presenting the edges in the LCD and the gradients in the LEDs. And so if you do that perfectly you should truly be able to get a much higher dynamic range of display. >> Yes, I mean that's quite [INDISTINCT]. >> MCCANN: Yeah, yeah. But the question is, do you--do they do it perfectly? >> Well. >> MCCANN: That's a very complicated question. Well, thank you very much. It's been fun to talk to you.