Blending in Photoshop CS4 Melinda Kerr takes us through the art of the blend.
The beginning of the blend As creative folk, we have a wonderful knack of ignoring things when they get too technical. For most of us, our right-brain left years ago, tired of the lack of love and relentless mocking it received from its hyperactive sibling, the left-brain. It’s little wonder then that so many software functions are overlooked due to their geek speak. Take the layer blending modes in Photoshop CS4. They promise so much with fancy names like multiply, hard light, dissolve and luminosity, yet a quick look in many Photoshop help files reveals evil words like algorithms, percentages and the arch rival of all creatives… maths. Urgh. In reality, though, the layer blend modes are little rippers when it comes to fixing images and creating interesting effects. They’re non-destructive, versatile and quite frankly everywhere (seriously they breed like rabbits in Photoshop). And here’s the best thing – you don’t actually have to understand all of them to use them. By and large understanding the theory of only a handful will have you speaking fluent blending modes and impressing your arty-farty party friends in no time. Now for some maths you’ll really like Sure there are 25 layer blend modes listed in the dropdown menu of Photoshop CS4, but in reality they easily fit into six sections, and truth be told there are only three you really need to understand. The three sections you’ll use the most are darken, lighten and the contrast section. In these groups if you understand one mode, you pretty much understand them all. Check out this diagram.
Here’s how they work In short, blending modes affect the way the top layer blends with the layer below it. Depending on which blend mode you choose, you can make images look lighter, darker, more ‘contrasty’, a different colour or a handful of other styles. The first group in our layer blends a diagram we’ve called ‘whatever’ because it’s not really all that interesting. Normal is, well, normal – as in default, as in 100 percent opaque, as in nothing exciting to see here... move on. Dissolve is kind of like the annoying guy at the party. He has one trick (reproduces pixels randomly so things look a little pointilised) and pretty much that’s it. It’s probably not something you’ll use much, if ever, unless you are that annoying guy… in which case – go away. The ‘dark’ section modes you will use a lot. They ignore white, but blend the dark and black pixels making an image look darker. The lighten modes ignore black, but blend the lighter colours, thus making an image lighter. The contrast modes ignore mid grey, but still blend the light and dark pixels and as such creates contrast. To see it work in practice, here is an experiment you can do yourself.
1. Create a Photoshop file Make sure it has two layers. The top layer has a 100 percent black object, a 50 percent grey object and a 100 percent white object. The bottom layer is green.
2. Choose the top layer and go to the layer blend mode Choose Multiply... but wait before you do, ask yourself: if multiply comes from the ‘dark’ layer group what will the result be? Yup, you guessed it, it will ignore white pixels, so as you see the white object disappears, the 100 percent black remains the same because you can’t get darker than that, and the 50 percent grey object makes the pixels below it darker. Therefore the entire image becomes darker.
3. Now choose Screen It ignores black, so the 100 percent black disappears, the 100 percent white remains because you can’t get lighter than that and everything below the 50 percent grey becomes lighter. As such the entire image gets lighter.
4. Finally, choose overlay It ignores 50 percent grey, so the grey object disappears and the white and black objects remain. Thus the images will show greater contrast. By understanding these three modes you effectively have a good idea of how others in their sections work (give or take a few discrepancies). If you include normal and that annoying dissolve, that’s 19 out of 25 sorted before you’ve even ordered your second chai latte. As for the other blends, rather than explain them here, you can see their effect with a nifty little keyboard shortcut. Choose your move tool (V). Make sure the top layer is chosen in the layers box. Hold down the shift key and press the ‘-’ and ‘+’ tools. This will scroll through every layer blend style and give you an instant preview of what happens with each one. So now you know the theory how can you use it in practice? The most obvious use is to fix exposure. Here we have Jessie the wonder dog posing in an overexposed shot. Because she’s black and white, she’s a good test case. First, we create a new layer above our background layer. We can either just press CMD or CTRL J to duplicate the original layer or, if you wish to keep file size down, you can just choose a Levels adjustment layer and leave it untouched. It will ‘inherit’ the information on the bottom layer and allow you to work the blend modes just as effectively. In this case we want to blend the darker pixels while leaving the whites alone. So we activate the top layer and choose multiply. Shazam! Instant gratification. You can also try out the other modes in the ‘darken’ section to see the variations you can achieve.
before multiply
before overlay
after overlay
If two blends were too much, I could simply dull down the second blend by decreasing its opacity, effectively creating a ‘blend and a half’. As an example of using multiple blend modes in the same file, check out the following shot. The shot on the left (of a hot rock pool at Yellowstone National Park) is the original shot straight out of the camera. The shot on the right was achieved by combining a mix of layer blends just from the three main sections we’ve talked about: darken, lighten and contrast along with the opacity slider. Some blends were used more than once. In 15 minutes we had the shot on the right. It could do with more work, but it does show you what’s possible in a short period of time.
after multiply
Now, on to the underexposed shot. In this case we want to blend the lighter pixels while leaving the black and darker pixels alone. So we need to choose a mode from the ‘lighten’ section. We’ll choose Linear Dodge. Again the exposure is fixed in a flash.
before blend modes
after blend modes
We also used a couple of quick layer masks in there as well to determine which part of the image the blend mode affected. What are layer masks you ask? Well, that’s for the December issue of Desktop. In the meantime, happy shooting and remember, with any program fear not the names of the processes, just experiment with them until you find what works for you. Then gloat.
before linear dodge
after linear dodge
Finally, in the following shot Jess is exposed OK, but looks awfully flat. She needs contrast and that means a mode from the contrast section. Try Overlay. See, much better. Once you’ve used a blend mode you can use it immediately again to ‘multiply’ the effect of it. You can also use the most well-known blend mode of all – the opacity slider. Say I wanted to lighten the underexposed shot even more, I could go blend > lighten. Then create a duplicate layer of that new layer and choose blend > lighten again.
Some keyboard shortcuts relevant to this article: n Use the corresponding number on your keyboard to set the opacity level, e.g. if you want 80 percent opacity, press 8, for 50 percent, press 5 and so on. n To duplicate a layer press CTRL + J (WIN) CMD + J (Mac). n To cycle through blend modes press the move tool (V). Holding down the shift key and pressing the ‘+’ or ‘-’ key lets you toggle through the blend modes. Melinda Kerr is the founder of the Photography Campus (www.photographycampus.com), an online learning portal for photography and photographic post-production, which launches this month.