Without a doubt, my favourite new feature in Photoshop CS5 is the Mixer brush. When you see the demos of people using it, it looks great, but when I first got to use it, I was a bit confused. Each brush has 5 different attribute settings and then another 4 canvas settings to get your head around.
In this tutorial I will take you through some of the mixer brush settings and demonstrate how to use them to make a fantasy based image with 2 of the biggest rats ever to blight a city. Let’s get started!
The following resources were used to complete this tutorial.
Before You Begin
For those of you with any version of Photoshop older than CS5 you will still be able to follow most of this tutorial, and certainly all of the art theory here should still be useful to you, but the mixer brush features are one of Photoshop CS5's main selling points to artists and are a good step above what you can achieve in older versions. A word of warning: The Mixer brush is a very complex thing for Photoshop to run and you may find that you paint faster than Photoshop can handle resulting in a crash, so save often. I learned this the hard way.
Before we get started: a very quick explanation about the mixer brush settings in the Brush Panel. - Bristles is pretty self-explanatory, the higher the number, the more bristles you have in your brush. You can get some interesting results with a very low bristle count. - Length is generally better when set to a high percentage as the bristles have more likelihood of dragging on the canvas. - Thickness you don't really need me to explain - Stiffness is one of the more important settings as a lower degree of Stiffness means that the bristles will splay in different directions and give a much more natural effect than brushes have previously in PS. Lowering the Stiffness percentage will make your brushes a lot more interesting and versatile. - Angle is the setting I've played with the least; I'll tell you more when I know it - Spacing is the same as it is in previous versions; increasing the spacing means the brush will re-draw itself less frequently. In summary, brushes with fairly long and soft bristles give the best painting results. Right, enough chatting, let's get to work!
Start up by setting your workspace to "Painting" which you can find in the top right of Photoshop. Then open a new A4 PSD file at 300dpi. Fantasy based illustrations are generally more convincing when they're informed by reality so find some reference of rats to help you when you're sketching out your rough. I used some photos of my old pet rat George, but rats are all pretty similar so a quick Google search will be fine here. Create a layer and name it "Roughs". Select the Brush Tool (B) and use the "DC pencil" brush (in the download pack) to draw your roughs, but don't worry too much about being accurate or working things up to a finished level as we'll deal with a lot of the detail in later stages.
When you're happy with your roughs, create a new layer called "Lines" and use the "DC inking CS5" preset to draw in your lines. Again, don't feel the need to be too detailed with your lines, as we'll be suggesting a lot of detail in the painting stages. Because we've kept the roughs vague I always have a bit of fun at this stage and improvise lots of details as I go along.
Open the photo of the sky. Select All (Cmd/Ctrl + A) then Copy and Paste it (Cmd/Ctrl + C and Cmd/Ctrl + V respectively) into your main image and then Free Transform it to fit the top of your image (Cmd/Ctrl + T). Don't worry about keeping it in perspective as we're just using this as a basis for some mixer brush painting later. Fill the background with Foreground Colour (Shift + backspace) with a neutral purple colour to help set a colour scheme, then switch to the Linear Gradient tool (g) and use a darker purple to start adding a few small gradients from the bottom of the page heading up to start adding a feeling of depth to the image. Never paint on a white background as it'll throw your perceptions of colours.
Time for some mixer brush fun. Add a new layer and name it "Background Mixer Layer". Select a Mixer brush (B) with the following settings: Shape: Round Point, Bristles: 81%, Length: 163%, Thickness: 1%, Stiffness: 1%, Angle: 0, Spacing: 2%, and in the Mixer Mode dropdown menus select the following; Wet: 23%, Load: 96%, Mix: 60%, Flow: 100%. Because we've ticked "Sample all Layers" you'll need to hide the visibility of the Lines layer for now (click the eyeball icon in the layers palette) because we don't want the black lines mixing into our sky. Hold Alt to bring up the eyedropper to pick colours from the photo of the sky and move your brush around the canvas much as you would with a real brush. The mixer brush eyedropper will pick a variety of colours unless you tell it to Load Solid Colors Only in the drop down menu near the top left of Photoshop.
Note: You'll notice that your brush cursor will change it's configuration depending on how you hold your stylus, but if you're new to the mixer brush it's worth turning on the Bristle Brush Preview which you can find in the Brush Presets tab. This will show you what your brush is doing in real time so you'll get a better idea of what your stroke will be like. For example, if you hold your stylus directly vertical you will get a very thin line, whereas if you tilt it sideways you will cover a much larger surface area much like when you paint with the side of a brush.
Note: One of the cool things about the mixer brush is that when you have Sample all Layers turned on you can blend in colours from every layer that you have visible whether it's above or below the layer you're working on without it affecting them. In this case you'll see that we're blending all of the colours from the stock photo but if you hide the mixer layer the photo is still intact, so you can experiment with your painting and if you don't like it, delete it all and start again as the photo is untouched.
We've played around with the background enough for the time being so make the Lines layer visible and create a new layer (Cmd/Ctrl + Shift + N) to start colouring the rats. We don't want to pick up any of the background colours here so make sure you untick Sample All Layers. Still using the same brush, paint the main rat with a mixture of blood red and dark red, building up and mixing the colours as you go. The bristles of the brush aren't very stiff which means they're great for mixing as they splay everywhere but this also means they aren't great at keeping within the lines. Don't worry about this for now as you can just erase the overlap when you're done.
With both of the rats painted, make a new layer called "Secondary elements" where you can paint in the car, the bin and the signpost. Make your painting here very distressed and messy. There should be nothing left in this scene that looks undamaged. We don't know whether the rats have caused the damage or whether they're just witnesses to it. Use a mixture of purples blues and grays in keeping with the colour scheme.
Create a new layer called "City" and paint in the city blocks and road. For this we need a new set of Mixer Brush settings; Shape: Flat Angle, Bristles: 7%, Length: 186%, Thickness: 1%, Stiffness: 30%, Angle: 0%, Spacing: 1% and in the dropdown menus choose Wet: 1%, Load: 100%, Mix: 1%, Flow: 100%, and untick Sample All Layers. Things in the distance become blurry so the edges don't need to be too defined. Make sure the city buildings and road look dark and moody as we're going for a mysterious and pessimistic tone with this image. Add a small road fading into the distance which points towards the red rat to strengthen his position in the picture.
Create a layer named "Dark Foreground Elements" and paint in some pure black bits of half destroyed buildings. These serve two main purposes, the first is to create a sense of depth between the focal points and the viewer, and the second is that we can use them as a framing device with subtle 'pointers' that lead the viewers gaze towards the main areas of interest by pointing at them and stops the audiences attention from wandering to the edges of the image. When you're done with the foreground layer you'll need to add a Gaussian Blur to increase the depth of field feeling it gives but it's always worth holding off until near the end of the image before doing this as if you need to alter it at a later stage it's trickier to add elements and make the blur match.
Create a new layer above the rats called "Shadows" and tick "Use previous layer as clipping mask". Set the layer to Color Burn and 50% opacity. Using a dark purple colour, paint the shadows on the rats. Because the clipping mask only lets you paint on existing pixels you don't have to worry about keeping in the lines. When using a shadow layer, always try to use local colours because they will help tie the images colour scheme together. Here we use purple, but if the sky were blue we'd use a blue colour to add the shadows. All colours are affected by the colours around them.
Create a new layer called "Highlights" and set it to 'Overlay' and 50% opacity. Pick a light pink from the sky and paint over areas that more light would hit such as the red rat's head and back and the road by the car. We're assuming there's a light source somewhere on the left hand side of the scene.
Create a new layer called "Rim lighting". Rim lighting is a technique used to give your images a greater feeling of depth and draw more attention to your focal points by highlighting the contours of your subjects and making them stand out from the background. Rim lighting (also known as back lighting) should normally come from somewhere behind the focal points to help definition of the forms. Use a solid pink to highlight the left-hand edges of the foreground elements (in this case the rats and the car). Concentrate on only adding rim light to the areas where light would hit and be aware that certain body parts would block the light from landing on all of one side (eg. Only portions of the red rat's tail are being hit by the rim light as its arm and head are casting shadow over a lot of its tail). Use a less saturated pink for the blue rat's rim lighting because light appears less saturated the further away it is from the viewer.
Add some rubble in the mid-ground on the secondary elements layer to suggest the destruction in the area. Adding small touches like this in the background can add to the overall narrative and make the viewer question what went on in the scene. Back on the rim lighting payer, paint in the glowing effects on the eyes of the rats. Draw in the strange glowing scars that surround their eyes. Again this will let the audience know there is something more to these rats than being simply overgrown.
Create a new layer called "Edits" and add a small yellow radial gradient over the eyes to make them appear as if they're glowing with power. With all glows, use a radial gradient set to approx 25% opacity and "foreground to transparent" start with the glow colour first (in this case yellow) and then use a smaller pure white radial gradient in the middle of the glow's source, as the centre is always brightest.
Create a layer called "Overlay" and set the blending mode to Overlay. Use the radial gradient tool, again picking a light pink from the sky, and apply it in small areas that light would hit the areas in both the foreground and background. Overlay layers are brilliant as they react with the layers below but don't obscure them so the colours in your image will become richer without covering any details you have painted. Also use your paintbrush with the same pink and add a few brush strokes over the highlighted areas to enhance the variation further.
Now we're nearing the end of the illustration we can start playing around with blurring elements, so click on the "dark foreground elements" layer and apply a Gaussian blur of 5.5 pixels (Go to Filter > Blur > Gaussian Blur) which will knock it out of focus nicely. Use the lasso tool to draw a selection around the skyscrapers on the "city" layer and apply a Gaussian blur of 3.9 pixels.
Open up a concrete texture jpeg (we used texture number 170843, but anything similar could work just as well) select all of the document and then copy and paste the contents back into the main image above the "city" layer and below the "secondary elements" layer. Free transform (press Cmd/Ctrl + T) it so that the texture covers the roads just below the signpost and set the blending mode to Overlay. Apply a Gaussian Blur of 1.1px just to reduce the detail a little so that the texture is still present but not too sharp as the human eye is naturally drawn to sharper definition. We want the floor to support the image, not steal attention from it.
Back on the "Edits" layer use a variety of speckled brushes to add dust particles in the air, bits of dirt on all of the foreground elements and some small energy flares from the rat's eyes. Lock the visibility on the Lines layer by clicking the small padlock icon in the layers palette. Much like a clipping mask this means that you can't add any new pixels to the layer, you can only alter the existing ones. Use appropriate colours such as red for the fur and pink for the tail and paint over the black lines to make them blend with the picture more. You can also add some reflected light from off of the rat's tail onto the lower side of his arm to give it more definition and stop it blending into the rest of his body.
The signpost is a bit too sharp and is only a minor focal point so we need to make it stand out a little less. Use the lasso tool (l) to draw a very close selection around the signpost and press Shift + Cmd/Ctrl + C to copy all visible layers and then Paste it (Cmd/Ctrl + V) above the "Overlay" layer in the layer stack. Apply a Gaussian Blur of 2.8 pixels to make the definition a little softer which will make the signpost recede into the background.
Note: When you get near to the end of your painting it's always worth taking a look over it and working out which areas would be blurred in a photo. It's then a simple matter of repeating what you've just done with the signpost here and blurring the elements after you've copied them to their own layer. It doesn't have to be individual items either; this will work well on sections of a person's body too eg. If a character was swinging their arm backwards in preparation to punch someone a Copy Merged section of their arm would look great pasted onto it's own layer with a Motion Blur applied to it (Filter > Blur > Motion blur).
To stop the picture looking too "digitally clean" we can add a digital grain which will add a little texture without affecting your colours like dropping in a paper texture can. I got this tip from the excellent Dan Luvisi. Create a new layer at the top of the layer stack and name it "grain". Fill the layer with a colour of R:125 G:125 B:125, then go to Filter > Noise > Add Noise, with amount set to 400%, distribution to Gaussian and tick the monochromatic box, and click ok. Then select Filter > Brush Strokes > Spatter, with a spray radius of 10 and smoothness 5, and click ok. Then hit Cmd/Ctrl + F to repeat the Spatter effect again. Finally go to Filter > Blur > Blur (NOT Gaussian Blur) and set the layer to Overlay and 10% opacity. The grain effect will obviously look different on each image you apply it to so you'll have to alter the opacity manually and judge it by eye. As a rule of thumb the opacity should be somewhere between 5% and 20%. Any more than that and the texture starts to overpower the image and becomes distracting.
In traditional painting a glaze is a layer of paint thinned with a medium so that it becomes fairly transparent and is then applied over the finished painting to give it a little extra warmth and texture. We can recreate a similar effect by making a new layer at the top of the layer stack set to Soft Light and 50% opacity then select the mixer brush and set the mixing mode to "moist" from the dropdown menu and use a light pink to paint over the image, ensuring "Sample all layers" is checked to get the most from this effect. Don't worry about the black lines affecting anything here as the effect is very subtle.