The change from summer to autumn is a wonderful time for photographers. The most dramatic indication of the seasonal shift is the change seen in tree leaves. This can provide photographic opportunities as long as you have access to the right scene.

For those not lucky enough to see autumn colours in natural situations, it's easy to simulate the appearance of this seasonal change using Adobe Photoshop. Photoshop has a useful command in the Image-Adjustments menu, Replace Colour, that's just right for changing a specific colour or a range of colours in an image to a different colour.

Opposite we demonstrate one method of changing the green leaves of a summer scene into the mixed colours of an autumn landscape.

For both this walkthrough we've used Adobe Photoshop, but similar effects can be achieved using Photoshop Elements and Paint Shop Pro.

TURN SUMMER SCENES INTO AUTUMN VISTAS

1 Since autumn is most often associated with the changing colour of trees, we've chosen a particularly leafy scene for this workshop. We need a separate working layer for our edits, so hit <Ctrl>, <A>, then <Ctrl>, <C> to select and copy the entire image. Then click Layers-New-Layer from the top menu.

2 Paste the image into the new layer and choose Replace Color from the Image-Adjustments menu. Use the eye-droppers to select the colours to be changed. Use the Fuzziness slider to control the spread. In the Replacement section, move the Hue and Saturation sliders to obtain a golden yellow look, and then click OK.

3 Where the colours of different elements of an image are similar, the Replace Color command can inadvertently alter areas you didn't want it to. Go to Layers-Add Layer Mask and choose Hide Selection, then use the lasso tool to draw around the area to be hidden. Include any trees you want to change to a second colour.

4 To make the composition more interesting and simulate the way in which different trees change colour at different times, add a bright red colour to some of the trees in the scene. To do this simply repeat step two, but use different colour values in the Replace Color command dialogue box.

5 Add a layer mask to the red tree layer and hide those areas not required. Change the Blend mode of the red layer to Color and the yellow layer Blend mode to Screen for more integration with the colours underneath. Adjust the Opacity of the layers for a more subtle effect.

6 Finally, to give the image a feeling of warm light, add a Photo Filter adjustment layer above the original background image using the settings.

TIPS & TRICKS

MONITOR CALIBRATION MADE SIMPLE

Colours differ markedly when they're displayed on a screen, on printed artwork and with the naked eye. When working with colour adjustments, it's important that you use a standard measure, calibrating your monitor to match those of your photo editing software and any ICC colour profile you've specified within it. Spyder2Express (www.colorvision.ch/products/cat_digitalimaging.php) clings on to the front of your screen while its sensor takes a reading with which it is then able to fine-tune your screen setup.

ADOBE PHOTOSHOP ELEMENTS 5.0 If Adobe's Creative Suite 2 version of Photoshop feels like overkill, try Elements 5.0. It offers improved colour and lighting controls, curves and lens distortion tools plus colour-to-monochrome conversion (www.adobe.com/au).

HELPFUL DOWNLOADS

FULL-BLOWN PHOTOSHOP

Photoshop, the popular professional image editor, forms the basis of this month's tutorial. It is vastly capable but, with far less pricey image editors coming on in leaps and bounds, you probably want to try before you buy (www.adobe.com/downloads).

PHOTO-SHARING FUN

One of the more interesting photo-sharing sites is Flickr, where you can have a gander at other people's creative efforts, post your own and generally get lost in photo heaven. A Creative Commons Licence agreement means you can copy other people's work for non-commercial use (www.flickr.com).

iSTOCKING FILLER

If you need pictures for a brochure, so you can make greetings cards, marketing materials or, indeed, anything else you can think of, browse istock, a royalty-free archive of images, for suitable, competitively priced artwork. You can buy excellent shots for a few dollars (www.istockphoto.com).