It is popular to use digital imaging techniques to combine two pictures to form a third image, but the trick is to make sure you pick the right two images.

It pays to be thinking about these combinations at the taking stage and that is what we did when we visited Biggin Hill air fair recently with our digital camera. The day was awful with such low cloud that hardly any flying took place at all and the only subjects that we could find were the static displays. However, we noticed the German fighter on display (below) and also a guy dressed in the uniform of a German pilot (below) and hit on the idea right away of placing these two elements together using Adobe Photoshop. In fact they were some distance apart, but the two subjects were natural subjects to combine.

The benefits of being aware of what you are planning to do later are obvious. You can position your subjects so that they give you the best composition. You can see that the day was less than perfect and we decided to replace the dull sky while we were carrying out the rest of the manipulation.

We started by removing the unwanted sky and other detail from the aircraft picture. Regular readers will know that there are many ways to make your selections and the magic wand is often one of the best, but in such conditions where the sky and the subject are similar tones I find the pen tool is my favourite and I have shown a path on the image below..

It looks a tedious process, but with a little practice it's remarkably quick and you do have ultimate control. With your image greatly enlarged mark a path around your subject using the pen tool in short strokes. The strokes can be longer on straighter edges and shorter to negotiate curves. Try to keep your path just inside your subject, but not too much that you are losing areas that you want. Attention to detail at this stage is well worth the effort.

Having marked around the entire subject, select the layers palette (F7) and rename the thumbnail. Remember that Photoshop cannot create a transparency from the default background and that is our next task.

Select the path palette and drag the path down over the dotted ring at the bottom of the palette, which will convert your path into a selection or marching ants as they are sometimes called.

Tip............... Always feather the edge of your selections before removing any unwanted detail. The amount will vary depending on the resolution you are working in, but for a digital file such as this 1-2 pixels are about right. This slight softening of the edges may not appear to make much sense after all we want our images to be sharp. However, take a close look at the edges of any sharp image and under magnification they are not as sharp as they first look. Many cut and pastes are spoilt because the edges are hard and unnatural. Softness is the key and the feather command is found in the select menu.

Remove the unwanted detail by selecting cut from the menu bar, which will leave you with your transparency below.

If when you hit the cut command your aircraft disappears, don't worry. Click undo from the menu bar or use the quick keys of Ctrl+Z and simply inverse your selection. All that has happened is that you had your subject selected and not the unwanted detail. The inverse command is found in the select menu or via the quick keys of Ctrl+shift+I. Save your work regularly and carry out the same process on your pilot to remove the unwanted detail.

Select a suitable sky, which must balance with your subject and amalgamate all three elements using the layers palette in Photoshop. Working with layers can appear very difficult to grasp at first, but they are the key to good work and a little perseverance is worth it. To add one layer to another you should have the two images on screen together. Grab the thumbnail from within the layers palette and drag it onto the other picture on screen. You can then alter how the layers stack by simply dragging the thumbnails into the position you require.

With a subject of this nature the colour may not add an awful lot to the end result, so try reducing it to monochrome by desaturating it. When you remove colour from your subject, you will often find that the contrast will need increasing and you can achieve this using either the levels command or the brightness/contrast command from the menu bar.

A nice touch may be to add that little bit of warmth to your image by adding a sepia effect. This is simply done using the hue/saturation command in Photoshop. Tick the colorize box in the hue/saturation palette and move the sliders to get the tone you want. Remember that the techniques described here are fairly universal to most image editing software so if you are not using Photoshop follow the tricks and tips and use your own chosen software to get the same results.