GIMP: Add special effects to photos
Fancy getting more creative in your photography? Mike Bedford offers some inspiration by introducing a few special effects for you to explore.
Fancy getting more creative in your photography? Mike Bedford introduces a few special effects for you to explore.
The phrase “special effects” in photography can mean different things to different people. For some it means using an app on a phone to distort your selfie or, perhaps, to add a dog’s nose and tongue to your face. Others use PC software or smartphone apps to generate a range of pre-determined effects with a press of a button.
However, there’s plenty of scope for applying effects using photo-editing software such as GIMP. This is our theme here but with one key caveat. Our emphasis is on effects that’ll exercise your grey matter rather more than, for example, just adjusting the Hue in an image’s HLS colour definition to introduce some bizarre colours. We don’t say that from a patronising or disapproving viewpoint but, quite simply, because if anything is so simple to achieve then it’s likely to be an overused effect. Indeed, the word “Photoshopped” has almost taken on a derogatory meaning in some quarters.
So, having spelled out some of the effects we’re not going to cover, we ought to say just what we are covering, but that’s not easy to sum up because we’re using the scattergun approach. All our techniques can be effective, and by introducing such a diverse range of effects, we trust that your creative juices will start flowing. This tutorial won’t show you “how to do special effects photography”. However, we do provide you with sufficient guidance to reproduce our selected methods to provide a practical introduction to special effects, which you can explore in your own photo projects.
Tricolour images
We struggled to come up with a descriptive name for our first effect, but it offers the interesting combination of a photo that mostly looks normal, but with moving objects “jazzed up”. This can be as subtle or as extreme as you like, depending mostly on the scene. In common with some of our other effects, this can’t be done just by post-processing, so you need to consider it when you take your photos.
First, you need to take three identical photos of the same scene, so that means using a tripod. In our example, it didn’t matter how long we left between those three exposures, so we took them as rapidly as possible, so the lighting wouldn’t change between them. Depending on your subject, though, and in particular how quickly things are moving, you might need to leave a longer gap.
Turning to the post-processing, load your three photos into GIMP as layers. As with all our instructions here, you could use any fully featured photo editor, but you’d have to figure out for yourself exactly how to perform each function that we describe.
With the first photo selected, choose Components> Extract Component… from the Colors menu. Then, in the Extract Component dialog, select RGB Red as the Component before clicking OK. That layer will change to a black and white image, specifically one containing the red component of the colour photo. Now, in much the same way, extract the green component from the second photo and the blue component from the third.
At this stage, while all three layers appear to be greyscale, the image will actually be RGB but, for the next step to work, it must genuinely be greyscale. To convert it, select Greyscale from Image>mode. Finally,
select Components>compose from the Colors menu and then, in the Compose dialog, accept the default values and click OK. The result is an image in which the stationary parts look normal, but with a splash of colour in anything that was moving.
Invisible light
Back in LXF248 we provided guidance on taking photographs in infrared – that portion of the electromagnetic spectrum just longer in wavelength than red light. No mention of special effects photography could be complete without reference to this technique.
Traditional infrared photography is a form of black and white photography, although our tutorial also investigated methods by which an infrared and a normal colour shot of the same scene can be combined to create various false colour effects. Unlike anything that could be done from a single colour photo by editing, it has a unique effect by virtue of it making use of the infrared light that our eyes just can’t see.
A technique we didn’t cover, however, involves processing a single image taken with an infrared filter over the lens, and takes account of the fact that the red, green and blue elements of some camera’s sensors respond differently to different parts of the infrared spectrum. For best results, this requires the camera to undergo an infrared conversion, although it’s not necessarily impossible without doing so. This can give create some impressive effects, albeit quite bizarre in nature as you can see from the example shown here.
Infrared versus ultraviolet
Talk of infrared might raise the question of whether you can photograph in ultraviolet, this time the invisible light just shorter in wavelength than violet light. Well, yes you can but, for various reasons, it’s not easy and it’s not cheap. For this reason, it’s not commonly used for artistic purposes but for scientific use and forensics.
However, while we can’t easily take photos using UV, it’s possible to photograph an effect produced by UV. That effect is called fluorescence and is the emission of visible light by some substances when they’re illuminated with UV. The effect can be impressive with fluorescing objects appearing to glow.
Fluorescence photography is often used by mineralogists because many minerals exhibit fluorescence, but there are artistic opportunities here too. Ideally, we suggest that you arrange for some nonfluorescent objects to be in the scene too, illuminated with ordinary light, so there’s a contrast with the fluorescent content of the scene. This requires careful lighting or, alternatively, you could merge two photos: one taken in white light and the other in UV.
You do need something fluorescent, of course, and for your initial experiments you might like to use a gin and tonic as we’ve done here (see page 84). Actually, you don’t need the gin – it’s the quinine in tonic water that fluoresces. Having tried your hand with tonic water,
for more variety in the colour of fluorescence, you’ll need to get hold of some fluorescent dyes that fluoresce in a different colour to the blue of tonic water.
Coloured line drawings
Our next form of special effects photography will exercise your artistic skills rather more. This is another technique that doesn’t require any special attention when taking the initial shot, although you’ll need to know what types of subject will provide the best results – something you’ll soon learn by trial and error. Initially, though, go for scenes with bold shapes and lots of contrast. In a nutshell, we’re now going to convert the photograph to something that looks like a colourwashed line drawing.
The first stage in the process is to convert the colour image into a black and white line drawing. There are software solutions that will do this with a single click or, perhaps, which require you to make only a few decisions. GIMP doesn’t offer this process as a single operation, but because some of the steps have their own settings it means that you have a lot more scope to fine-tune the result.
With your photo opened in GIMP, your first step is to select an edge detection tool. Although we’ll later convert the image to black and white, we’re using the Outline tool first so it’s able to take account of differences in colour as well as differences in brightness. There are several such tools under Edge-detect in the Filters menu, and to start it might be a good idea to try them out to get a feel for what each of them does. Some of them have settings that will affect the width of the lines in the resultant line drawing.
Having carried out the edge detection, the result still doesn’t look much like a line drawing. First of all, there’ll probably still be some colour in the scene so the next job is to select Desaturate>desaturate… in the Colors menu and accept the defaults in the Desaturate dialog before clicking OK. Second, for most of the edge detection options your line drawing will be white on black, but we need the opposite. In that case, select Invert from the Colors menu.
We’re now getting closer to the effect we need but you can further fine-tune it using the Curves tool in the Colors menu. Unlike using this tool in normal photo editing, you’ll probably need to edit the default straight line curve substantially, probably to a curve that starts horizontal in the bottom-left corner and ends close to vertical at the top-right. As with all aspects of creative special effects photography, once you understand the principles, just play around with the setting until you produce a pleasing solution.
Once you’re happy with the line drawing, the final job is to colour wash it and here there are lots of options. You could mimic the colours in the original photo, you could adapt that process by colouring only parts of the image leaving the remainder as just the black and white line drawing, or you could abandon reality entirely, colouring the scene to achieve an artistic effect.
Your next step is to add a new layer by selecting New Layer… from the Layer menu. Then, in the Create a New Layer dialog, select Darken only as the mode – this will cause anything you paint on that layer to only colour the white areas while leaving the black lines black – and choose the fill colour before clicking OK. Often that fill colour will be white, although if you want to colour large parts of the scene in a particular colour, choose that colour to reduce the amount of painting you’ll have to do later. In choosing colours to paint on the new layer, although we wouldn’t want to stifle your creativity, we suggest initially that you start with desaturated colours to better emulate the colour washing effect.
Finally, with the new layer selected, paint the scene as you wish. If you feel that your colours are a bit too garish, you can make the effect more subtle by reducing the opacity of the layer on which you added the colour.
Intentional blurring
Generally speaking, sharp photos are considered good while blurred photos are thought of as failures. As with many things, though, we’d like to suggest that there are exceptions to that rule and, in particular, a blurred photo
can be a good one, in an artistic sort of way. However, we’re not talking of just a bit of blur, but of some rather excessive blurring and there are at least three way you could achieve that.
Before we begin, we need to admit that this effect doesn’t involve any photo processing at all. However, despite us being passionate about all things computingrelated, we thought it would be rather narrow-minded to include only special effects involving software. Indeed, we believe that a well-rounded photographer will make use of all available techniques irrespective of whether photo processing is involved.
Methods of blurring the subject
The first way of introducing blur is to use a moderately long exposure and to pan the camera while you’re shooting. You’ve probably seen photos in which the photographer has panned a fast moving Formula One car, thereby compensating for its movement and rendering it sharp, while the background appears as blurred lines suggesting speed.
Our suggested effect is similar although it doesn’t necessarily involve panning a moving object. Instead, you might pan a totally static scene, rendering it all as a linear blur to provide a somewhat abstract effect. This method has been used effectively, for example, in scanning upwards while shooting a forest scene, the end result echoing the shape of the tree trunks, albeit with a look that’s not too dissimilar to an impressionist painting.
The second way of introducing blur also involves using a reasonably long exposure, but instead of panning the camera, you should zoom the lens while you’re shooting. Before saying any more, though, we need to point out that this isn’t for everyone. Specifically, this won’t be possible on a device in which zooming is controlled using zoom-in and zoom-out buttons. Instead, you need a camera that’s zoomed by rotating a ring on the lens, so that pretty much limits the technique to a DSLR or a so-called mirrorless camera.
It’s fairly obvious what sort of effect this will produce – but if it’s not just take a look at our example (below)– and except for pointing out that you ought to use a tripod, the only bit of guidance we’ll give is on suitable subjects. Anything with strong perspective – for example a street scene, with a viewpoint looking along the street – is always popular, as are objects with rotational symmetry such as a close-up of a flower head.
The third method is to rotate the camera while you’re shooting. Having discussed pan and zoom blur we don’t think we need to say any more about rotation blur, so we’ll leave you to come up with your own ideas. And finally, irrespective of what method you use to induce blur, we have to emphasise that you probably won’t have immediate success, but practice makes perfect.
Before leaving the topic of blurring, we need to make an admission. Despite our saying that these effects don’t involve post-processing, they can be added to an ordinary photo using GIMP, even though our preference is to achieve the effect while you’re shooting. It’s not as easy to do it in the camera, but the major advantage is that you know immediately whether you’ve got the effect you want. In contrast, if you’re relying on postprocessing then there’s an element of doubt as to whether the base photo is suitable.
We said in our introduction to this tutorial that we wouldn’t show you “how to do special effects photography” and we’ve been true to our word. However, we’ve certainly shown you how to achieve several particular special effects, and we trust that you’ll have some fun trying them out.
More than that, though, we hope that this investigation of special effects photography will inspire you to think outside the box. This might lead you to adapting some of the effects we’ve shown here. You might find ways of combing more than one effect or develop your own unique techniques. One way or another though, it’s our hope and expectation that this will represent a small step in your escaping from the uniformity of “me too” photography.
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