Secrets of the blend

Tom Arah Read more October 7, 2009

Last month, I looked at Photoshop’s tools for creating photorealistic montages, but seamless realism isn’t always the most important factor – sometimes the aim is sheer impact. So this month I’m looking at the tools Photoshop provides for original and creative composition. As you’ll be creating your composition from scratch, you first need to decide on the final output size and set up your image accordingly. The usual rule of thumb is to provide image resolution at least double the line screen spacing of the output, which for professional print is 150lpi, so 300dpi would be an appropriate resolution. In artistic projects, absolute detail is less important than in photographic work, so if necessary you could lower this to 200dpi to reduce memory and processing requirements. Your next task is to create a background against which your composited objects will be seen. The background must be attractive and dynamic enough to catch the eye but not distract. If the canvas doesn’t look right, neither will the project.

So where to begin? At first sight, Photoshop looks sparse in creative terms. You need to fill this canvas, but the Paint Bucket’s flat fills are hardly going to grab the eye. Pattern fill is more promising, as you can tile the background with a bitmap – perhaps a texture like clouds, rainforest trees, water or a stone wall – which immediately creates a theme and atmosphere. Applying a texture as a fill layer using the New Fill Layer | Pattern command opens up further options and lets you retrospectively and interactively change the pattern size. The problem is, even if you use a seamless tile, the repetitive grid becomes very obvious, distracting and dull.

Better to take advantage of Photoshop’s Pattern Maker filter. Say you want a background for a composition of African wildlife. Find an image of a leopard and select a rectangular area of its skin; paste it into your composition; scale it to approximately the right level of detail; copy it to the Clipboard; then use the Pattern Maker filter’s Use Image Size and Use Clipboard As Sample commands to generate several full-sized patterns based on this copied texture. Select the one you like the best. Pattern Maker is great for producing abstract backgrounds that remain at least subliminally recognisable, but you get no real control over the process and the resulting backgrounds still look quite uniform.

To add both control and variety, you can turn to the Gradient tool (shortcut G toggles it with Paint Bucket). Its properties bar lets you select from dozens of preset gradients, or mix your own and apply them interactively in five modes: linear, radial, angle, reflected and diamond. Gradients can also be applied as fill layers for easy fine-tuning. Their range of colours and tones offers a lot of scope when it comes to blending, and unlike uniform abstract patterns their inherent light and shade adds dynamism and depth. However, the default gradient options are too simple, smooth and clinical, too clearly computer-generated: they need more ‘character’.

There are various ways to achieve this, although they only work for directly applied gradients or fill layers that have been rasterised. Photoshop CS2’s Mesh Warp transformation can stretch the layer as if it were rubber, while the Liquify filter enables interactive swirling, puckering, bloating, pushing, mirroring and turbulence effects. You can even save your meshes to reapply to other backgrounds. With the Filter Gallery command, it’s possible to quickly trawl through dozens of processing filters that make the resulting gradient pattern more artistic, human and less artificial.
One set of Photoshop filters isn’t made available from the Filter Gallery and so often gets overlooked, but can prove especially useful for abstract backgrounds; namely, the Render effects. The most useful are Clouds and Clouds Difference, which apply randomly generated colour values between the current foreground and background to yield gradient cloud effects (reapplying Cloud Difference creates marble-style veining). The Render | Fibers filter works in a similar way to produce an effect reminiscent of woven cloth or animal fur.

Filters offer a good start for adding interest to your background, but if you get into original compositing in a big way you’ll certainly want more creative options. There are many third-party filters that specialise in abstract effects, starting with Ulead’s freeware ArtTexture effects (www.ulead.com), through excellent budget collections like Andrew Buckle’s wide-ranging one at www.graphicxtras.com or Harry Heim’s HyperTyle (www.thepluginsite.com), up to high-end professional options like the FiberOptix, FraxFlame, FraxExplorer and GradientLab effects in Corel’s KPT Collection. I’m also a big fan of standalone texture generators such as Texture Maker, Genetica and Dark Tree. And finally, Adobe Illustrator can fill one of Photoshop’s most obvious gaps with its ability to create gradient meshes.

Layer upon Layer

So far, I’ve been talking about creating a background as a single layer, but Photoshop’s creative power is really unleashed once you start compositing and blending on multiple layers. Try filling one layer with a distorted and filtered gradient fill, then overlay it with another layer created with the Render | Clouds filters. Now select the overlying layer and reduce its overall opacity in the Layers palette – the composition springs to life as the tonal and colour range of the gradient combines with the granularity and visual interest of the pattern.

Most users never go beyond applying a uniform transparency, but this is to miss a lot. Rather than setting a flat opacity level via the Layers palette, double-click the overlying cloud pattern’s thumbnail to call up the Layer Style dialog’s Blending Options, whose advanced transparency options include interactive sliders that let you show or hide the underlying layer on a pixel-by-pixel basis, depending on the strength of either layer’s grey level. This effect is little used in photographic montage, but it’s strikingly effective with abstract images built from tonal gradients, allowing the lower layer to melt through the upper in a highly organic fashion. Such tonal blending can create striking effects, but for each pixel, transparency is still either on or off and there’s no interactive control over where the transparency is applied.

For maximum control, you need Layer Masks, which control a layer’s transparency based on a greyscale map. Create two layers based on different distorted and filtered gradients or patterns, then select the top layer and apply the Layer Mask | Reveal All command. Now paint onto the selected layer mask with a grey brush to partially reveal the underlying layer or, for more immediate and equally eye-catching results, simply apply a gradient or one of the Render filters to the mask. You can control the strength of the blending effect by applying a Levels adjustment, either globally or locally to feathered selections within the mask.
Layer-based transparency opens up enormous creative potential, but its possibilities pale alongside those offered by Photoshop’s wide range of blend modes (22 at the last count, ranging from Colour Burn through to Vivid Light). Blend modes work their magic by combining the colour values of each overlying and underlying pixel based on an equation, a strictly mathematical process whose results are nevertheless unpredictable and often beautiful. Try overlaying two gradients or patterns and then changing the mode of the top layer in the Layers palette (use the cursor keys to quickly move through options without reselecting the drop-down). As the result depends entirely on the content of the layers, explore them all and choose whichever one immediately stands out as best suited to the project in hand. Each blend mode creates new features and points of interest, while the overall effect seems more organic and natural – a semi-transparent pattern overlying a gradient can look semi-detached, but an inverted, multiplied or colour-burned pattern becomes a seamless part of a much more integrated and interesting whole. And remember you can still vary the opacity between the blended layers, to get the right mix between the subtle and the striking.

So far, I’ve been concentrating on tools for building a background from large-scale patterns and small-scale textures, but I haven’t mentioned colour – and for good reason. Once you begin exploring blend modes, colours will change constantly and dramatically. This isn’t a problem but rather an opportunity, as Photoshop enables you to manipulate colours retrospectively, for example, by duplicating and flattening the image and applying commands from the Adjust menu.

However, for more flexibility, apply colour correction via the New Adjustment Layer command: as well as preserving all component layers and layer masks live for future editing, the adjustment layer can be retrospectively fine-tuned by simply double-clicking on it in the Layers palette. Useful options to apply as adjustment layers include Levels and Curves to manage your background’s tonal range, or Selective Colour, Channel Mixer and especially Hue/Saturation to manage its colours. When creating abstract designs, perhaps the most powerful adjustment is the underappreciated Gradient Map command, which works by mapping the underlying greyscale values into new colours and tones – it’s particularly well suited to tonally rich abstract images. Load this command and a range of gradient libraries and you can simply click on the preview thumbnails to explore a near-infinite range of colour possibilities, from subtle variations on a single-colour theme to wildly varying psychedelic rainbow effects. Once you’ve found the gradient that produces the most attractive and appropriate effect, click on its preview in the Gradient Map dialog and an editor appears in which you can interactively fine-tune the defining gradient knots, while the colours and tones of your background update in real-time.

Pasting the pieces

Now you’ve created an eye-catching, attractive and appropriate abstract background, you’re ready to bring together and overlay your other compositional elements. Using the various selection tools I covered last month, you can isolate objects from photographs and paste them into your composition as separate layers, ready for resizing, rotating and distorting. When first pasted, these imported elements will almost certainly stand out like sore thumbs as their photographic quality clashes with the abstract background. However, by using the tools I’ve just described – most notably layer masks and blend modes – you can soon make them seem an integrated and natural part of the overall composition, while retaining their recognisability.
Blend modes are particularly effective here, as many work by moving the blended object’s highlights and shadows toward solid white or black, giving it a strong silhouette effect (and hence a clear identity), while at the same time the mid-tones are merged organically into the background. Often the unforeseen result of a blend mode is so striking you can just gratefully accept it and move on to the next object, but in other cases you’ll want to fine-tune it. Select your object’s pixels by Ctrl-clicking on its layer thumbnail before applying any desired correction, as this automatically adds a layer mask to the adjustment layer, ensuring the image background remains unaffected. You can even hide the object layer itself so it’s only present in the overall composition as a colour or tonal shift in the abstract background.

Since you’re creating original artwork rather than a photorealistic montage, you also have the advantage of being able to look beyond bitmapped images to vector shapes and text (which can instantly provide your composition with a clear theme and focus). You might expect that vector objects would clash even more with your textured abstract background, but in fact their pin-sharp outlines and default flat colours make for a clear and eye-catching contrast. And, of course, those same tricks for producing more organic blending – varying opacity and blend mode – are still available. For vector shape layers, you can also use the Change Layer Content command to swap between flat colour, gradient, pattern and adjustment layer formatting effects (with text you’ll need to convert it to a shape layer first).

There’s always a danger that the objects you’ve added to your composition become so organically blended with their background they lose all recognisability and you end up with an attractive pattern without obvious meaningful content. To avoid this pitfall, Photoshop provides the ability to apply layer effects via the Layer Style command, available from the Layer menu or at the bottom of the Layers Palette. Ten main options are available – drop shadow, inner shadow, outer glow, inner glow, bevel and emboss, satin, colour overlay, gradient overlay, pattern overlay and stroke – each of which can be used to create a subtle (or not so subtle) distance between overlaid objects and their background.

It will come as no surprise that the level of control over layer effects is comprehensive – for example, the Bevel and Emboss tab lets you independently set the colour, opacity and blend mode of both shadow and highlight. You can also combine effects, simply by ticking the checkbox next to their name in the central Layer Style dialog. For consistency and efficiency, each layer’s context menu permits quick copying and pasting from one layer to another, and you can save all parameters, including blend options, as a style that can be applied to future compositions from the Styles palette. This palette also offers a range of preset styles and it’s well worth exploring them to see how they produce their results.

By now, your head’s probably spinning at the range of creative options on offer – patterns, gradients, fill layers, filters, opacity settings, layer masks, blend modes, adjustment layers, layer effects and styles – and the potential ways they all interact. By changing a single blend mode, opacity setting or adjustment layer, you can instantly create a totally different compositional effect. Most importantly, thanks to blend modes, there’s an inherent unpredictability to the compositing process that means you can’t really set out toward a particular end effect but must rather creatively experiment, going with the flow to find the best result.
But just what is the best result? Creative experimenting can produce so many possible end results, some subtly different, some dramatically so. Is the version on the screen in front of you now really more successful than the radically different one you were looking at five minutes ago? In short, how do you ever stop composing and decide on a winner? Every time you’re satisfied that you’ve finished exploring a particular creative avenue, you could export the results for later comparison, but this is clearly wasteful and awkward. (Alternatively, you could use the History palette to take snapshots of all contenders, although these will be lost as soon as you close the file.)

Much the best course, though, is to exploit what is perhaps Photoshop’s most powerful compositing feature: Layer Comps. Using this palette, you can store the current state of all layers, including their Visibility, Position and Layer Style (in other words, all settings that can be altered in the Layer Style dialog, including opacity and blend mode) as a Layer Comp. Whenever you create a composition you think has a lot going for it, store it as a Layer Comp and then, by adding new layers or changing existing layer styles, including blend mode and opacity, head off in another direction entirely. At any point, you can return to the Layer Comp palette to review your candidates by restoring their saved layer settings.

This system is by no means perfect, as Layer Comps only store layer palette settings (so if you pixel-edit a layer or layer mask, all previous comps will be affected); they can’t cope if you delete a layer (so hide it instead); and they don’t store adjustment layer settings (so duplicate and hide the original). Also, in an ideal world, Photoshop would bring filters fully into the Layer Comp fold, so that they too could be applied non-destructively as both layer effects and adjustment layers. In the meantime, though, Photoshop offers more than enough creative potential and possibilities to keep anyone happy – while it made its name with photorealistic compositing, ultimately its creative compositing power proves just as impressive.