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Current time:0:00Total duration:11:56

Video transcript

so this is a video about the elements of linear perspective with a little bit of history thrown in I love linear perspective it's hard not to love linear perspective it's like this magic formula well look what even palette with chela was able to do just a few decades after linear perspective was first discovered so linear perspective is a way of recreating the 3-dimensional world on a two-dimensional surface and it's really accurate well look at this Paolo Uccello look at this study of a chalice this wasn't done on a computer this was done with pen and ink on paper no Photoshop no Photoshop so let's give a little bit of historical background and then we'll talk about how it's done okay so let's start first with what the problem was okay so here we have a painting from the early 1300s by an artist named Ichi Oh who's painting in Siena and you can see that duccio's interested in creating an earthly space for his figure of angel gabriel and mary but that the space doesn't really make sense okay so what you're saying is that we have a kind of a real room here we can see the beams in the ceiling we can see the architecture we can see the doors and so he's really interested in putting these figures in a real place the problem is and by the way don't get me wrong I love do CHEO but the problem is is the do chew is not constructing that architectural space in a way that looks logical to our eye and I think you know it probably wasn't a problem for du Chia but it was a problem for artists about a hundred years later who had a different goal and their goal was a kind of really accurate realism on that flat surface okay but before we leave the doochie oh let's spend just a moment being kind of unfair and finding what's wrong okay so for one thing the beams of the ceiling right up here don't agree spatially with the seat that the Virgin Mary is on or with this little stand for the Bible that we see here or for that matter with the lines that are constructed by the top of the capitals of these blasters so none of this is really making sense right it's not a national space and there's this increasing interest in the 1400s in rationalism that's the period that we really call the Renaissance right the early Renaissance and so in Florence in 1420 Brunelleschi and let's put up a picture of Brunelleschi okay so he's right here Filippo Brunelleschi and he discovers or some would say rediscovers because some think that maybe the ancient Greeks and Romans had this before but he discovers linear perspective so he was a genius he was a Renaissance man he was an architect he was an engineer he was a sculptor and according to tradition he had gone down to Rome and he was studying ancient Roman buildings ruins and he wanted to be able to sketch them accurately and he developed this system linear perspective as a way of doing that and in 1420 in Florence he demonstrated the system and 15 years later another brilliant Renaissance man Albert II codified what Brunelleschi had discovered he explained the system of linear perspective for artists so he publishes a book called on painting in 1435 and we have a later version of that book right here and inside that book he really gives the formula for linear perspective and that's what we have here so let's just spend a moment talking about how this system works okay so let's go down here and let's actually do a diagram of linear perspective okay now I cannot do palette Roux chela's chalice but I can draw a basic linear perspective of structure okay go for it okay so first of all we need to understand that one-point linear perspective sometimes called scientific perspective is made up of three basic elements there's a vanishing point there is a horizon line and there are orthogonals so let's start off with just creating a simple interior I'm going to draw just a rectangle here so this is your painting this is your flat surface that's exactly right and I'm going to decide that the vanishing point needs to be pretty much in the middle okay so I'm putting a vanishing point right about here okay okay now let's see why don't you label that VP so we remember it's vanishing okay so that's the vanishing point now what I want to do is I want to create a series of rays that move down to the bottom line and these one could think of as kind of floorboards in a room right and artists have been able to do this long before linear perspective artists had never had a problem with this right well that's because they were constructing it intuitively and intuitively when you look around at the world you see walls in a room that look as though if they continue they would meet or the floorboards look as though they would need so it's kind of intuitive so I'm actually going to add not only a floor to this room but I'm going to put in a couple of windows will just make it very simple here so put in a couple of more verticals right here and then I'm simply going to have all of this meet in the middle at that vanishing point now I'm going to use an eraser here just to clean this up just a little bit so we get rid of some of the extraneous lines just to make things a little more clear and well you can sort of see a window okay good there window to form but now here's the problem the problem was if you didn't want to have floorboards and instead you wanted to have a tile floor you had a problem because you know intuitively the horizontal lines have to get closer together as they go back in space the problem is it's hard to exactly figure out what those proportions are as they get denser and denser as they go back in space so that the floor doesn't look like it's popping up which happened often actually in paintings from the trecento so the idea is that the tiles get smaller and smaller because things generally get smaller and smaller as they move away from us in space or appear that way at least so what a birdie wrote down and on painting was that you need to have a second point in space outside of the picture plane that was at the level of your eye so I'm just going to put it here it's at the same level as the vanishing point right and so we would call this of course what this is H this is the horizon line and whatever and I missed it but there is okay and then what I would do and I would of course do this more accurately with a ruler is I would draw another series of rays from that second point from the exterior point that's right and have it connect to each of those floorboards right and so as you can see what's happening is that that angle becomes more extreme as I move across right and I'm doing a freehand so it's a little bit hard to see but you get the point now something really interesting just happened which is I can now create a horizontal line that is at that first intersection do you see that right there mm-hmm going straight across I see it then I can draw a second one at that second intersection right there and so forth and they get more and more compressed as I go back in space and the illusion should be them a kind of compression in space so I think this will become more clear if I just do a little bit of a racing now okay while you're erasing I want to talk about that word illusion okay because I think it's key to everything here absolutely what artists are looking to do is to create an illusion of reality on this two-dimensional surface Alberti set a painting should be like a window so in a way you don't see the two-dimensional surfaces two-dimensional surface become something you look through to a world that is a continuation of our own world so the idea of the illusion being incredibly convincing was so important to the artists of the Renaissance artists like Masaccio or later Piero della Francesca or Andrea Montaigne and so now I'm just going to fill in a few of these tiles alternating so you really can get a sense of that floor in space whoops so is that working so even in this rough way here on this tablet this is working basically it actually couldn't be rough equipment but I think it still makes the point if I were then finally to get rid of these lines and in fact get rid of the vanishing point entirely and instead now draw in a back wall we have something that comes fairly close to looking like an interior space now what about putting figures in ah so now you're really asking for trouble let's say so if I were to draw a figure what I would like to do is make sure that the eye level of the figure is approximately at the horizon line so I would put that figure in just about here and what if you put a figure more in the foreground or more in the background so if I put a figure that was more in the foreground I would still want their eye level to be at that imaginary horizon line but of course now they would be larger right so I think this is the part that's counterintuitive the heads are on the same level and it's the feet that are on different levels that's exactly right and Alberti also said that that eye level that horizon line would ideally also be the viewers eye level so that the perspective would really work perfectly okay so we have orthogonals the diagonal lines that meet at the vanishing point we know the vanishing point is a point on the horizon line and we understand how these correspond to the viewer and to creating an illusion of space let's take a look at what somebody who can really draw does with us okay let's take a look at Leonardo da Vinci's the Last Supper okay so not you not me at all someone who can really draw okay so here is Leonardo's Last Supper immediately the interesting thing is that after Brunelleschi discovers linear perspective artists like Masaccio begin to use it but they realize that in addition to creating an illusion of space it has a way of bringing the viewers attention to the vanishing point so artists begin to use it not just to create that illusion but they begin to use it expressively and that's what we really see here was Leonardo so not only is Leonardo creating this beautiful perspect rival space but he's also focusing our attention on Jesus Christ at the center who is the vanishing point it brings our eye our attention to the divine so here we see the ignored owes Last Supper and we can certainly just intuitively make out the orthogonals in the vanishing point but let's go down and really look at the diagram okay here we are so it's interesting they are eye level all across is basically at the horizon line and of course we see the vanishing point the point where all of the orthogonals intersect which is right here and so we have all of these lines that are moving across this this with the surface of this wall and they are all bringing our eye right to Jesus Christ in the center and those lines are orthogonal lines and there you have it that's how it works linear perspective you