This tutorial is sort of a continuation of the Gritty Pipelines Tutorial
. You certainly don't have to work on top of the base wall texture from there, but if you're unfamiliar with some basic photoshop methods you may want to read it first.
Now we're going to move on to putting a light on our base wall texture. Open that texture up and make a round selection in the center. With a fairly neutral color selected, go to edit -> fill -> foreground color. Then go to select -> modify -> contract. I set mine to 20 pixels, but you can make this whatever size you prefer. When you hit ok you'll notice that our selection has shrunk by 20 pixels (Image A). Hit the delete key. We are now left with a thick ring that will act as a border to our light (Image B). Now we're going to make a very basic bevel for our ring. We're going to use two selection tricks for this. One is the shift key. While holding down the shift key and making a selection, it will lock your marquee into a perfect circle or square as you drag. Second is the space bar. If you hold down the space bar and make a selection, it allows you to move it around on the screen. We're going to do both of these at the same time, to give us the most control over our selection. Over the top of your ring, make a circle within it (Image C). When you have it the size that you want, go up to layer -> new -> via cut. This will cut out your selection and move it to its own layer. Now you can work with them as two separate pieces. Lighten the center part of the ring using either the dodge tool or by going up to image -> adjustments -> brightness contrast. Now we have a very simple 3-dimensional border (Image D). Very simple..
The light needs to look like it is actual mounted on the wall, that it affects the surface its on. So, there needs to be a bit of shadow and wear around it. Using the burn tool (set to midtones) darken the textured wall below the ring. Personally, I like to duplicate the background layer so that if I screw up I can simply delete the layer I've been working on and make another. With a fine 1-3 pixel brush, draw in a few cracks at the edges. This is great to do with a mouse because your hand is a tiny bit unsteady. The color I use for my cracks is just a few steps darker than the darkest brown in my base texture, or a selection from the area within the ring that we've just darkened. To make the cracks a little more convincing, go back around the edges of them with a lighter color. The dodge tool set to midtones or highlights can work well for this step too (Image A). Continue working your way around the edges until you are pleased with the result
By now I've combined the two ring layers together to make my work easier, but you certainly don't have to do that yourself. :) I'm starting to build up some of the texture on the ring (Image A). If you like, you can use the same methods we did on the pipes - or you can handpaint it as I'm doing. Either way we want to get away from the smooth, solid look we currently have. Go in with the eraser tool and wear away the edges of the ring. You can also paint some chips into it. While I'm zoomed in, I go over some of the hard edges of the ring (for instance the top edge of the bevel) and put some hard highlights in place (Image B). Continue building up texture and form until you're pleased with the outcome (Image C). This is just something that takes a little effort on the artist's part, there is no quick Photoshop fix to make it look good.