From the course: Deke's Techniques (2018-2021)

877 Posterizing colors nondestructively

From the course: Deke's Techniques (2018-2021)

877 Posterizing colors nondestructively

- Hey gang, this is Deke McClelland. Welcome to Deke's techniques. Last week I showed you how to create a piece of posterized false color artwork using Photoshop's Paint Bucket Tool, which is a very old tool that actually predates Photoshop by six years when Bill Atkinson created it for the very first version of MacPaint. Compare that to using a Gradient Map adjustment layer, which came along much later and, no offense, Bill, the man is a legend people, is a lot more flexible. And even though the feature is called Gradient Map, it's just the thing for creating abrupt color transitions without even trying. Here, let me show Bill exactly how it works. All right, so here's the entirely non-destructive version of the artwork achieved using a Gradient Map adjustment layer. And so what we're going to do is start with the destructive version, the so-called destructive, because we used the Paint Bucket Tool in order to permanently modify pixels. Pixels that we could again modify later any time we wanted to, but still, there's a certain advantage to working non-destructively. So I'm going to take this bucket layer right here and I'm going to press the Backspace key or the Delete key on the Mac in order to get rid of it. And that way we've got just these two adjustment layers right here. The first is posterizing the artwork, so that we have just eight luminance levels per color channel. So eight times eight times eight for a possible total of 512 inside the full color composite. And then I went ahead and reduced the number of luminance levels to just eight using this Channel Mixer adjustment layer, which is set to Monochrome, as you can see, and we're just seeing the contents of the Red channel and nothing more. All right, now I want to add a Gradient Map adjustment layer and I want to name the layer as I create it, and so if I were working on the Mac I would press the Option key and left-click on this little black and white circle icon right here. Because I'm working on the PC I have to press the Alt key and then right-click on that icon in order to bring up this pop-up menu, at which point I will choose Gradient Map. At which point you should see the New Layer dialog box. I'll go ahead and call this layer colors and then press the Enter key or the Return key on the Mac. Now currently I'm replacing the luminance levels from black to white with this gradient right here that goes from black to white. So in other words we're not really making much of a difference. If you want to make a difference then go ahead and click on this gradient ramp in order to bring up the Gradient Editor dialog box. Now I'm going to start things off by replacing the blacks with that bright shade of yellow, so I'll go ahead and double-click on this color stop right here in order to bring up the Color Picker dialog box and I'll change the hue value to 50 degrees and I'll take both the saturation and brightness values up to 100% and then I'll click OK. Now obviously that's not exactly the effect I want, so I'll go ahead and replace the white with a dark shade of violet by double-clicking on this white color stop to bring up the Color Picker dialog box. I'll change the hue value to 270 degrees, and I'll set the saturation, once again, to 100%, and I'll take the brightness value down to 50%, and then I'll click OK. All right, now at this point we have this yellow to violet gradient that is replacing all of the luminance levels inside of the image. We need to add a few more color stops, a total of six incidentally in between. But where should they go? So notice that the first color stop here has a Location value of 0%, which is what we want, and the final one has a Location value of 100%. And since we want six more luminance levels we want to take that Location of 100% and divide it by seven. Let me show you what that looks like. I'll just go ahead and Alt or Option + drag a new color stop out, so because I have the Alt or Option key down I'm creating a copy of that color stop. And then I'll change its Location value to 100% divided by seven. Why seven? Because we've got a luminance level for black right here plus seven others. And so when I enter 100% divided by seven and press the Tab key I end up with this error message in my case. I think Photoshop is concerned that it can't do decimals. So it's coming up with the closest value, which is 14%, which is what I want. All right, so I'll go ahead and double-click on this new color stop here, which is totally the wrong color. And so basically what we're doing is we're saying I'm going to replace a 14% brightness, so a very dark gray, with what? And that what is going to be a hue value of 150 degrees, a saturation of 100%, and a brightness value of 0%, so very dark. And then I'll click OK. Now from this point on you just want to add 14 more degrees. So I'm going to start by Alt or Option + dragging this guy over just a little bit, so we're creating a new color stop. So any time you Alt or Option + drag you make a copy of the previous color stop. And I'll change this guy to 14 plus 14 and press the Tab key and that gives us 28%. And now I'll double-click on it, so that I can replace a very dark gray with a brightness of 28% with some other color, specifically it's going to have a hue value of 120 degrees, so I'm making the green more yellow, and then I'll Tab down to the brightness value and take it up to 30%, like so, and then I'll click OK. Now I want to remember 28% right there, but I've got to Alt or Option + drag this guy in order to make a copy of him, and then I'll change that Location value to 28 plus 14 and then I'll press the Tab key. That gives me 42. At which point I'll double-click on this guy and I'll take the hue value back up to 150 degrees, actually I need to press the Shift key as I'm pressing the up arrow key in order to get that value. And then I will Tab down to the brightness value and take it up to 60%, like so, and then click OK. We've got one more shade of green, so I'll just go ahead and Alt or Option + drag this guy and change its value to, what was it before? 42%, we need to change the Location value for this guy to 42 plus 14 and that's going to give us 56%. I'll go ahead and double-click on this guy, leave the hue value set to 150 degrees, take the saturation value down to 80%, and take the brightness value up to 80%, then click OK. All right, so that takes care of all the green. So we've got one yellow, we've got four greens, and that's going to leave us with the three violets. We already have one of the violets, so I'll go ahead and Alt or Option + drag this guy down, like so, so we create a copy. And now I'll set its Location value to 100% minus 14 and I'll press the Tab key in order to let Photoshop do the math. So notice we now have a Location of 86% and I'll go ahead and double-click on this guy and I'll leave the hue value set to 270 degrees. I'm going to take the saturation value down to 70 and I'll take the brightness value up to 90% and then I'll click OK. And now, remember that this guy's 86%, I'll Alt or Option + drag him to make a copy, now the Location's 81%, who cares, not what I want. I'll change that value to 86 minus 14 and press the Tab key. I get 72%, at which point I'll double-click on this guy and I will take the saturation value even further down to just 30%, like so, and then I'll take the brightness value up to 100%, and I'll click OK in order to accept that complete gradient. Now if you want to name it you could go ahead and give it a new name, such as Poster colors, if you like, and then you would click on the New button in order to create a new gradient, like so. Now that step is not necessary, by the way, you don't have to do it. I just want you to know that you can go ahead and save the gradient if you like. At which point I'll click OK in order to accept that change. And then I'll hide my Properties panel. And as you can see, if I turn off that colors layer this is before, this is after. I can even turn off the other layers if I want. I don't know what this is going to look like, but I'll go ahead and turn off the channel and poster layers and I end up with this effect here. And then when I turn poster back on I get some posterization. And then when I turn the channel layer back on I get even more posterization, like so. So a Gradient Map adjustment layer gives you a degree of freedom you just can't achieve using the old school Paint Bucket Tool. And that is how you create a false color posterization effect entirely non-destructively using a combination of three adjustment layers, culminating with a Gradient Map layer here inside Photoshop. Now posterized artwork what with its abrupt color transitions is all very well and good, but what if you're looking for false color artwork with smoother transitions? Well, in that case I have a follow-up movie that shows you how to do exactly that. If you're looking forward to next week well, that's when I show you how to hide the Film Strip panel that comes up even when you have just one image open in Camera Raw. Deke's Techniques, each and every week, keep watching.

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