Traditionally, many photographers use a range of filters, either of the screw-in glass variety or the plastic rectangular filter-plus-holder combo. These filters fit onto the end of your lens and can produce a huge range of effects, from introducing gradients (Neutral Density Graduated filters) and stopping down your exposure (Neutral Density filters) to saturating colours and cutting down reflections on water and glass (Circular Polarisers, for example). There are filters that soften your image, for a flattering, ‘glowing’ effect, filters that create a starburst effect and coloured filters that are great for shooting high-contrast black-and-white photos… the list goes on.

The alternative Photoshop’s latest software releases offer an attractive option that can help photographers and digital artists simulate the effects generated by some of the tangible filters on the market with the Photo Filter feature.

Although it’s not enough to make us want to ditch our much-loved set of filters, the Photo Filter feature does bear some relation to the way in which physical filters are used to modify the properties of the image recorded by the photographer.

Accessed via the Image> Adjustments menu or by selecting Layer>New Adjustment Layer>Photo Filter, the Photo Filter option offers you the choice of selecting a filter type and colour, then adjusting the density of the filter to produce the final effect. This is a crude method of adjusting the colour balance of your photograph, but it’s a useful means of learning about the effect of using filters in your photography. While the dialog does look incredibly simple, there are ways of adjusting it to meet your needs.

Conventionally, tangible filters were of great importance in film photography, in order to correct for colour casts caused by the varying colour temperatures of different light sources. With the invention of digital photography, this is no longer necessary, as colour casts can be corrected for in-camera, using your camera’s white balance presets, or they can be removed digitally post-shoot if necessary.

Hot and cold: Using filters can change the ‘temperature’ of an image. On the left a warming filter has been applied and on the right a cooling filter

Photoshop’s Photo Filter options represent a method of not only quickly removing colour casts, but intentionally introducing them to create a particular effect.

When creating a digital masterpiece, you often have an image in your mind that you want to create. Say you want to generate a moody portrait of a brooding artist, but your image straight out of the camera was shot under tungsten lighting and it looks far too warm and optimistic. Simply add a Photo Filter adjustment layer. Click Layer>New Adjustment Layer>Photo Filter, then in the dialog box, select a Cooling Filter and experiment with the Density slider until you’ve introduced enough blue into your shot to emulate the atmosphere you had in mind to begin with.

For more surreal effects, experiment with the other colours available, adding red, green or emerald casts to your images. For digital artists it’s not always about realism, and you can use this over photomanipulation projects to give atmosphere and effect.

For greater control over the final look of your image, you can create your own photo filters using Lab values in Photoshop. Open an image with a colour cast that you want to correct and click Image>Mode>Lab Color. Select the Eyedropper tool, hold down Shift and click on an area where there should be a neutral tone. Note the a and b values down, then add a new Photo Filter adjustment layer. Use the Color Picker to select the point you clicked on before, displaying the Lab values for that colour. Invert the a and b values, adding a minus in front of a positive value and vice versa, before clicking OK. Increase the Density in the Photo Filter dialog box until your colour cast is neutralised. If the effect needs to be intensified, simply duplicate your adjustment layer and adjust the Density slider until you achieve the desired result.

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Lab correction method – Before (left): A little too warm. Set image mode to Lab, hold down Shift and use the Eyedropper tool to select where there should be neutral colour. After (right): When you have applied the Photo Filter, adjust the Density slider to achieve the desired result

Photoshop’s Photo Filters offer enough options to get you started, but there’s a whole host of third party plug-ins out there that can increase the creative possibilities even further.

Tiffen – one of the leading manufacturers in optical photographic filters – has a set of digital filters available, called Dfx. Available from www.tiffen.com, Dfx offers a range of filters that expand the capabilities offered by Photoshop’s Photo Filters. The digital filters included in the Dfx software simulate the effects of optical glass filters, matching the Kodak Wratten industry standard, making Dfx not only a versatile creative tool, but a learning resource too.

If you’re feeling particularly adventurous, have a go at creating your own ‘filters’ in Photoshop. To simulate the effect of a Neutral Density Graduated filter (ND Grad), enhancing the sky for example, simply add a gradient to your image. Add a new adjustment layer to your image, and set your Foreground Color to black, leaving your Background Color white. Next, select the Gradient tool, picking the Linear Gradient setting from the toolbar. Set the Foreground to Transparent and drag the Gradient tool from the top of the sky in your image to the horizon. Finally, experiment with the Opacity slider until you’re happy with the final effect.

Learning how to use filters effectively can make a huge difference to your photography, so it’s worth experimenting with them. Next time a colour shift is called for in your photos, use the Photo Filters in Photoshop to take control of the look and feel of your images, and create the photograph you originally had in mind.