Painting metallic tileable textures
Teo KiKi takes us through some of the key aspects in painting a metal tileable texture in Photoshop.
The main point to remember when creating your tileable texture is to make the appearance as generic as possible, as it will be tiled over a model surface.
Color map: Background
We'll begin with a color map. First, reference your callout sheet and analyze it. Then, as we'll be painting metal, we need to start with a black background.
Color map: adding color
Pick the complementary colors on your reference image and using a Cloudy brush, paint the basic color variations into the image. Here, this example uses red and blue as most types of painted metal have a very powdery look.
Color map: patterns
When you are done adding color to the base, you can start extracting patterns from reference photos.
Color map: contrast
Using the RGB channel, look for the channel with the highest contrast on the image. Duplicate the channel and adjust the curve for more contrast.
Color map: select patterns
Now Ctrl+click the thumbnail of that channel to select the patterns.
Color map: ‘Select color range' function
Alternatively, you can duplicate the original layer, and use the ‘Select color range' function.
Color map: paste selection
Copy and paste your selection onto the base layer you painted earlier and adjust the Hue and Saturation to blend it in.
Color map: using photographs
Continue using photographs to get patterns. These can be anything, from tea stains to concrete, to achieve the effect in the metal reference. Keep your changes on separate layers. You can also play with the Opacity and layer modes: Overlay, Soft Light, Multiply, and so on, to make the patterns blend in. Use Curves, Hue/Saturation to refine the effect.
Color map: fixing gaps
After you copy and paste the patterns on, fix unnatural gaps in the texture by creating a Layer Mask. Mask out or paint over some of the patterns that have hard edges and seams.
Color map: scratches
Now, create a new layer, paint in the scratches with a custom brush and adjust the Opacity. The example below is painted with a 1 pixel standard hard-edged brush with the pressure turned on.
If you're satisfied with your texture now, we can move on. Save your PSD into a TIFF file for the next step.
Tiling the textures
Click on Filter > Other > Offset, and check the Wrap Around option. If your tile is sized at 2048 for example, then offset it by 1024 on the horizontal and vertical axes. Now you have a tileable texture, but with ugly seams down the middle.
To fix the seams, use the Clone tool to clone other parts of the texture onto the seams. Be careful not to touch the edges though.
Use a Hard brush that has breakup on the edges to refine your seams. Don't use a Soft brush because your texture will turn really blurry and muddy. Also don't use a Hard brush with no breakup on the edges, because you will get some funny-looking spheres in your texture.
When trying to create a uniform texture, the Healing brush is a better option than the Clone tool. This is because the Clone tool can easily make the image muddy. Using the Lasso tool is another good option – simply select an area that you want to use and feather the selection. Copy and paste it over the area you want to cover.
Specular map: using color maps
Based on your color map, make a specular map. Specular maps are in grayscale, and white indicates full specular and black indicates no specular.
In the PSD file for your color map, group all your color layers together, and name the group ‘Color.' Duplicate the ‘Color' group and name it ‘Spec.'
Specular map: Hue/Saturation
Add a Hue/Saturation adjustment layer on top of all the layers under the Spec group. Adjust the Saturation to -100.
Specular map: final map
Based on the look of material, decide which areas should have more specular and where will have less. Use Hue/Saturation and Curves to adjust the layers in the spec group. You should adjust it according to the areas that will be darker or lighter. For example, rust layers are darker and scratches are brighter. You're making decisions on what to make black or white in the texture. Remember that the map must have contrast.
Bump map: introduction
Bump maps are also based on color maps, and are also in grayscale. The level of bump indicates the nature of the 3D texture depth. White indicates a bump at 1%, black is -1.50%, and gray is for areas that are smooth with no bump.
So first, duplicate the Color group, and name it Bump.
Bump map: refining the map
Using Curves and Hue/Saturation, adjust the layers individually. Here, the rust layer needs to be brighter because of the slight lift from the surface of the texture, and the scratches layer needs to be darker because they sink below the surface. A 50% gray square is placed on the side for comparison in the image here. Remember to keep your bump from looking too noisy.