 Hopefully at some point in your life you'll have a chance to visit some of the famous painted caves in northern Spain. If you go to Altamira, you can't unfortunately enter the cave. They only let a very limited number of people in by lottery, but they have a wonderful presentation with a number of reproductions, and here they have sort of the step-by-step process of making a cave painting. Here's a close-up of some powdered red ochre, and one of the things that they've found in the cave are vessels and tools that would have been used to hold the paints, and also tools for grinding them. So a painter would have started with first kind of figuring out where they wanted to place something on the wall, and then they would have used the existing cracks and the existing contours of the wall to help them plan that. It started with engraving, simply scratching the design into the wall of the cave as you see here. Then the artist in this case at Altamira would draw using charcoal, and this is probably burnt bone or possibly plant material being used kind of the way that you would use chalk or a crayon. It can be used to draw on, but then since it's powdery, it's also possible to smooth it and blend it with the fingers as you see here, and get some three-dimensional effects of shading. Here the artist is also going over some of the engraved areas. Painting was then done with ochre pigment. Here we're seeing some of that red ochre, and the artist is just using hands to apply this paint, and also blending it to some degree with the charcoal to give the overall effect of this great bowl. One of the most exciting finds made at Altamira Cave is a painting tool that was used kind of like a primitive airbrush. It was a hollowed bird bone that was split in two pieces, and one portion would be held into a cup full of liquid paint, and then the other would be used to blow across the surface, and surface tension would draw the paint up through the one held in the bowl and cause paint to splatter on the wall of the cave. This was the technique that we see in many cave paintings, not just in Altamira, but in several other Spanish caves, and also up in France as well. Some of the most famous examples are painted hands at El Castillo Cave, not too far from Altamira, so let's see that clip very briefly. So you can see this is causing the paint to splatter onto the surface of the wall and create negative images of human hands. When I visited Altamira Cave to do research, of course I wasn't allowed into the cave itself, but I was allowed into their research and conservation lab, where they have a lot of really wonderful samples of ochre and tools. Here this is paint in shells. Those were used as little paint pods. Now we're panning over some of the ochre samples, and you can see the variety and range of colors that were found in the area and used in the cave. And then these are grindstones that were used to grind the ochre into a powder. It's really fascinating stuff. This last little clip that I want to show you is some video that my friend Janet Purdy, she's a graduate student doing advanced PhD work in art history here at Penn State. This is something that she acquired for me when she went to the Museum of Human Origins in Johannesburg, South Africa. And here they're demonstrating how ochre would have been ground and then some of the paints used with it. So let's see that video from Janet. Okay. So you've got the ochre underneath and you're pounding it. I'm pounding it to make this, which will be mixed with water or air and egg for it to stick, to be strong enough for the raw plantings. So these are the end products of it. Some of the stones will be white, some of them will be black. This one is short yellow. This one is a bit red. You've got to get a product of that.