Join Adam Crespi for an in-depth discussion in this video Generating the base matrix and creating a selection for color, part of 3D Textures: Granite & Mosaics.
- Granite is a versatile building material and it's as old as, well, since people figured out how to stack stones. It's an igneous rock. Meaning it was formed by cooling magma and with that has no real internal structure. It's fairly uniform and granular. I'm going to draw some granite here in Photoshop. And we can use this granite for cladding buildings. For accents and other materials such as brick. We can use granite for flooring and counter tops inside, or even as paper weights or dishes.
I'll start out by gathering some reference and then come back to Photoshop and draw a large base of granite that then I can use in flooring, for example. In a quick search for granite we can see the general structure that there's chips of different rocks and other minerals in a matrix and as noted there's no real defined structure, it is a massive stone. Meaning it is fairly monolithic and uniform throughout. It's not layered like slate, for example. With granite then what we need to do is consider the matrix color and three, four, maybe even five chip or matrix colors in there of different stone so we can adjust them.
What we can see also is there are so many different colors available. It's really only limited by what the stone supplier has and what you'd like to use in, let's say your counter top. We use granite then in flooring and the neat thing to note here is that one, it can be cut and polished, and two, there's always dividing lines between the tiles in some way and we can exploit these patterns if we'd like. Diagonal lay in the tile for example opens up a room by letting that grid flow. We can also vary them through or even add in marble and granite in a more refined pattern.
Again we need our large base to get going with and then we can cut our tiles from it. With counter tops we can see much of the same thing. Many granite counter tops are cut from a single slab. And they're prized for their figuring and veining through there. We receive variations in the structure in the granite and also quite wild colors occasionally. Usually they compliment the cabinetry and other fixtures. But we need to keep in mind that we've got to draw a big enough sample of granite to cut a counter top from. Terrazzo then is a composite.
It's a poured stone. It's an artificial construction. Where we take granite and quartz and other rocks and minerals and put them into a mix, a binder, and pour them into a mold. The mold being on the floor. With terrazzo then we need metal, and these provide splines between the different pieces. Allowing us to make intricate designs, medallions, and so forth in our flooring. We can even pour it for counter tops and it's even got modern derivatives such as solid surface. Where we start to see the best attributes of granite and terrazzo in well as much of the uniform material as we like for as many counter tops as we can stand.
What we'll do then is jump back into Photoshop, and start by drawing a large base document to drive our selection to get the matrices in the right place. Here in Photoshop I'm going to start out with a new document. Choosing File, New, and I'm going to make this new doc 5,000 square. I'm running in pixels, RGB color, and 8-bit. And right now my working profile is SRGB. If you're going to color manage this is the place to start, but as I don't have a designated program yet this is going to I'm going to leave alone the Color Profile.
I'm going to work in square pixels. I'll start out my new document and it starts out in the default colors. White background and black foreground. I'm going to fill it with some gray. Pressing Shift + F5 and pulling up the Fill dialogue. And choosing under Contents, 50% gray. This way when I start to run some filters on it to generate some random noise and patterns in here. It's got something to operate on that allows us latitude above and below in value on this gray. Now I'll choose Filter and Filter Gallery.
What I'll do is change over to Grain and I'm going to make sure that I have only one filter here. What you're seeing is that at some point I have used a previous filter. So they're stacking in. I'll delete one and make sure this first one is set to grain and I'm going to use a grain type here of clumped. The Grain is always a uniformed size depending on the Grain Type. We can vary Intensity and Contrast but to get more Grain we need a larger document. What I'll do is bump up the Intensity and Contrast.
So I've got pretty good definition between the colors and click OK. With my grain applied I'll press Z and zoom in on it to see how it looks. It's pretty good. I've got some fairly defined areas in here. And lots of uniformly spread blobs. Now I’ll get a selection going. These layers we're going to make will be a selection. They won't actually feature in the final texture, but they'll help drive the selection to get a uniform distribution of grain within my granite. I'll press W for my magic wand and I'm going to turn on Anti-alias but leave Contiguous off.
I'll try a Tolerance of 12 and see how that looks. Sampling one of the bright pinks for example. What we can see is it gives me a pretty good distribution of small blob shaped marquees throughout but it's not quite enough. I'll bring up this Tolerance to 20 and try it again. This time I'll try selecting one of the greens. This is better so I'll add to it. Adding to the selection is a big help. Because this way we can pick one, hold shift, pick another green, and add that in till we get a good distribution.
With a couple colors picked what we can see here is a more or less even distribution of these blobs throughout. They're all roughly in the same range. Nothing is excessively big or small, and they're nicely spread. Pressing Control + 0 to zoom out shows us a sparkling document. Those are all the little marquees. And this'll be my first selection then in my granite. I'll zoom in and the reason I'm zooming in this close is to see what happens when I fill them to make sure it's working. Now I'll make a new layer, and I'll pick any other color that I can recognize.
In this case a bright red. I'll press G for the paint bucket, and I've got Anti-alias off on my paint bucket. I'll click once in one of the marquees to fill. And what I get are nice contrasting red blobs. There's some feathering from the selection. Because there was some partial selection going on but overall I've got really defined chips in this matrix. I'll repeat the process maybe three or four times more. Again going back to the background layer, leaving the red layer on so I can see where not to select.
Using my magic wand on, this time, the purple and making a new layer and filling that in. I'll fill this time in a bright yellow. What I'm looking for is an even distribution, and that's the big deal. That we should see more or less a uniform grain structure in our stone. The aforementioned noted massive. I'll grab a dark purple and this looks like a little too much. If you're finding you're selecting too much bring down that Tolerance. Here's that 12 again.
There's a purple selection and it looks better. And again I'll fill it in. When I construct textures as a side note, I use fairly bright colors and I realize these are not going to show up on the final stone. But visually they tell me very clearly where part of the texture is or is not. Now rather than working in the blacks, whites, and grays I might see in granite, red, yellow, blue, and green in this case will tell me exactly where the incidents of those chips are. I'll run this one more time.
This time I'll grab a light green and hold shift to add to that selection taking in a dark purple. I don't mind if some of the chips are colliding as it'll look good still in the final. One more new layer, a different color that's easily recognized, and a fill. And there is the matrix for my granite. Now at the moment it looks like technicolor static. That's okay. Here's what happens. We turn off the background and turn on a new layer or create one and fill it in something else, let's say an even gray.
What we get is a great distribution through of all these flecks. It's ready to be granite and we can customize the colors as needed but this incidence of these little chips throughout really lets us know where the granite grain is so we can judge if we have enough of a particular color. We might want a gold fleck through and a black granite. Or we might want a white granite with charcoals and deep ebonies in there. This pattern, easily recognizable then, lets us, well, recognize where that grain sits and is a good first step prior to adding figuring into that granite.
Find more installments in this series—on textures like slate, concrete, and brick—on Adam's author page.