Almost since the concept of composition was first introduced, photographers have found all kinds of ways to get it wrong. Lamp posts growing out of people's heads, dust spots on film, and people's legs walking into or out of a frame can all conspire to ruin an otherwise great shot.

Luckily, the ability to remove these objects from photos is almost as old as the medium itself, and as is the case with most aspects of photography, the digital practice is unbelievably easy.

It's known as cloning, because you're copying and pasting an area of your photograph over the top of another, effectively deleting an object from a photo.

The uses are myriad. Have you ever taken an otherwise perfect landscape photo with an articulated lorry on a distant road? Cloning can remove it. Is there another photographer in the background ruining your shot of a zoo animal? A quick wave of the cloning tool can make it look as if you were the only one there.

Cloning needs to be done with finesse, though. Although recent versions of popular editing software like Photoshop Elements and GIMP have made cloning easier, it's increasingly tempting to reach for the clone tool at the drop of a hat, when what you actually need is the lightest of touches. Read on the find out how to make distracting elements of your shots invisible, invisibly.

Choosing your shot

As with most photo-editing techniques, you shouldn't view the clone tool as a magical implement that can clear up even the most cluttered backgrounds.

For example, you need to remember that any object you remove has to be replaced with nearby detail. The sharper that detail is, the harder it will be to invisibly transplant over the top of an unwanted object.

You may find that removing a significantly sized feature - a person standing in front of a church, for example - may be impossible without making it obvious that you've been tinkering. Also remember that if there's lots of detail behind the object you're getting rid of, you'll effectively have to re-draw that hidden detail by hand - a stern test of your artistic abilities.

Example 1

CHOOSE WISELY: Although the cars ruin this image, removing them with a clone brush is impossible - the parts to be removed outweigh the usable bits of the photo

Instead, the clone tool is best used to correct images that only need relatively small objects and features removed to perfect them - the larger the object, the more work you'll be making for yourself.

The clone tool

The clone tool is only available in relatively heavy-duty editing software. This isn't, for example, something you can do with free software like Picnik, the online photo editor, or even the often surprisingly powerful Google Picasa.

Instead, you'll need what's known as a per-pixel image editor. Some editors, including earlier versions of Lightroom and Picasa, only let you make wholesale changes to your images, rather than giving you the ability to edit highly specific bits of them.

You need to be extremely precise when using the clone tool - you don't necessarily need to be able to zoom your image to 100 per cent and work on individual pixels, but you still need a piece of software that will give you a reasonable amount of flexibility and power.

Pick your software

There are several options to consider. If you haven't already committed to a piece of software, we continue to recommend Adobe's Photoshop Elements 9 (£60), which offers a good blend of editing power and library tools. Don't worry if you've spent money elsewhere, though - the likes of PaintShop Pro (£44) and Serif's PhotoPlus X4 (£60) also offer cloning.

Alternatively, if you'd rather save some cash, GIMP is open source, totally free and very powerful, as long as you can put up with what we'll call 'usability quirks'.

When you use the clone brush, you'll be working at very close quarters with your image, which makes it easy to lose track of precisely what you're doing, or what your efforts will look like once you're done. With that in mind, it's important to constantly check your work by zooming out of your image and making sure that the cloning you're doing is going to end up being invisible.

Once you've got the hang of the clone brush, there are a few tips that will speed you along and reduce the chance of you making any serious mistakes.

Firstly, remember that [Ctrl]+[Z] (the Undo command) is your friend. If you make a clumsy brushstroke, always use Undo rather than trying to correct your mistake by ploughing on.

You can ensure your final image's quality is as good as possible by opening the original, then saving it as a lossless format, like TIF or PSD. Saving a JPG multiple times results in a loss of image quality - bad news, since you'll want to save your progress frequently when working on an image to minimise the loss if your software crashes.

Working on a lossless copy also guarantees that no matter how big a mess you make, your original file will remain safe.

How it works

At its heart, the clone brush is fairly simple. To begin, you assign a point from which the brush should copy. When you click and drag the brush, the area you pre-selected is copied and pasted over the top of the other area. It's like selecting an area of your image and dragging it over the part you want to remove.

However, there's a huge amount of flexibility, which gives the clone brush its power. The ability to change brush sizes from very small to very large means you can work on all manner of objects, from telegraph wires to people. You can also "feather" the clone brush - that is, soften the brush's edge to make it less obvious that you've worked on your image.

There are pitfalls to beware of when you're using the clone tool. Making multiple brushstrokes - particularly when you're sampling from the same place with every click of the mouse - is a sure way to introduce a new and obviously fake texture into your image. This is because you're essentially copying and pasting the same small area of the image again and again. Follow the walkthrough below to find out how to get a smooth, unnoticeable effect.

Use the clone brush to remove distractions from your photos

1. Select the Clone Stamp tool

Step 1

This image of a pair of deer locking antlers is perfectly focused, well exposed and shows a great bit of natural behaviour. If only it weren't for the jarring passers-by in the background.

With the image converted to PSD format, select the Clone Stamp tool by pressing [S]. The square bracket keys are also handy for getting the brush size right without moving the mouse pointer.

2. Get a closer look

Step 2

Now we'll use the [Z] key to select the Magnifying Glass tool, and click to drag it around the main areas we want to clone.

You can zoom back out of your image using [Ctrl]+[0]. Alternatively, [Ctrl] and the [+] or [-] symbols will progressively zoom into or out of your shot. You should check that your work is effective - and difficult to spot - at every step, as mistakes caught early are easiest to fix.

3. Align your stamp

step 3

There are a few options on the Clone Stamp toolbar. The one to keep an eye on now is the 'Aligned' option.

If the box is checked, your selected clone point will change relative to the position of the mouse pointer when you begin your brush stroke. If it's clear, the place you choose to clone from will remain in the same place. Your choice here will depend on the job at hand; for now we'll select 'Aligned'.

4. Resize the cursor

Step 4

Press [Alt] and the cursor will change into a crosshair - clicking on your image will determine which part of the shot is cloned. In this case we want to clone the blurred greenery over the top of the person.

The next step is choosing the right cursor size - we'll go for something around two-thirds the width of the object we're painting over, which gives a good balance between speed and accuracy.

5. Start cloning

step 5

Removing objects is as easy as clicking and dragging over the object to remove - the clone stamp will recreate detail from your chosen area.

A steady hand and attention to detail will go a long way here - check your work after every stage to make sure you haven't inadvertently created a new feature that looks even worse than before. For fiddly bits, stop work and reduce the size of the cursor for more precision.

6. More challenging shots

step 6

This was a fairly simple case - the background we were using was out of focus, so there was no need to be particularly careful about which bits we used as clone points.

If the background had been in focus, it would have been important to make sure we weren't replicating big areas of detail. The basics are the same - just be prepared to spend more time if you're handling more detailed images.

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First published in PC Plus Issue 307

Liked this? Then check out How to isolate colour in photos

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