Layer blending modes

The Blending mode in the Layers palette isn’t only used to adjusting brightness levels. Once you’ve mastered the process of creating and editing layers, it can also be used to add great-looking special effects. Each blending mode has a different effect that will depend on the hue, saturation, contrast and brightness levels in the image you’re working on.

With most blending modes it can be difficult to predict exactly what the end result will be, although all modes provide a range of adjustments. The best way to gain a ‘feel’ for the adjustments provided by each blending mode, is to explore them using one or more of your image files.

In this feature, we’ll demonstrate some of the changes you can produce, starting with two radically different images. The first step is to select the images you’ll use and re-size them so they are the same size (and resolution).

With both image files opened in the image editor (we’ve used Adobe Photoshop CS4, but any editor that supports Layers can be used), click on the image for the upper layer and then Select > All from the top toolbar. Copy the image with Edit > Copy and paste it onto the lower image with Edit > Paste. The Layers palette should show two layers.

Once this has been done, you can begin to experiment with the various blending modes. An explanation of what each mode does plus an example showing the effect is provided.

A screen grab of the desktop in the image editor, showing the files that will be blended. The image of the sunset is the bottom layer, while the group of pears produces the upper layer, which will be overlaid on it.

Although you can only see the top layer, the two layers are shown in the Layers palette (circled in red). The circled area also contains a drop-down menu of Layer Blending modes and an Opacity slider for adjusting the strength of the blending.

Normal: this is the default setting that doesn’t apply any blending effects. However, you can adjust the upper layer to allow more of the lower layer to show through with the Opacity slider.

Dissolve: In this mode, random pixels from the upper layer are replaced with pixels from the lower layer, based on the opacity setting. No effect is seen when the Opacity slider is set on 100%. The Opacity slider was set to 55% for this image.

Darken: In this mode, darker colours in the upper layer are replaced with light colours from the lower layer. The Opacity slider was left at 100% for this image.

Multiply: The colour values of the two layers are combined, producing a result that is darker than either of the original layers. The Opacity slider was left at 100% for this image.

Colour Burn: As the layers are blended, this mode darkens the image and increases contrast. The Opacity slider was set to 55% for this image.

Linear Burn: This mode darkens the colours in the lower layer by subtracting the brightness value of the pixels in the upper layer. The Opacity slider was set to 75% for this image.

Darker Colour: This mode compares the colour values of the pixels in the upper and lower layers and displays the darker of the values. The Opacity slider was left at 100% for this image.

Lighten: This mode compares the brightness levels of the pixels in the upper and lower layers and displays the lighter of the values. The Opacity slider was set to 55% for this image.

Screen: This mode multiplies the inverse of the colour values for the upper and lower layers and always produces a lighter result. The Opacity slider was set to 85% for this image.

Colour Dodge: This mode decreases the contrast between the lower and upper layers. It always produces a lighter image. The Opacity slider was set to 75% for this image.

Linear Dodge: In this mode, the colours in the lower layer are lightened by adding the brightness values of the pixels in the upper layer. The Opacity slider was set to 55% for this image.

Lighter Colour: This mode compares the colour values of pixels in the upper layer with those in the lower layer and displays the higher values. The Opacity slider was set to 90% for this image.

Overlay: In this mode, the highlights and shadows in both layers are preserved and amplified in the blending process. The Opacity slider was left at 100% for this image.

Soft Light replicates the effect of a low-intensity spotlight and will lighten or darken the image, depending on the characteristics of the originals and the Opacity setting. The Opacity slider was left at 100% for this image.

Hard Light replicates the effect of a harsh spotlight and will lighten or darken the image, depending on the characteristics of the originals and the Opacity setting. The Opacity slider was left at 100% for this image.

Vivid Light adjusts colours according to their contrast values. If pixels on the upper layer are lighter than 50% grey, colours on the lower layer are dodged. When pixels on the upper layer are darker than 50%, pixels on the lower layer are burned. The Opacity slider was left at 100% for this image.

Linear Light adjusts colours according to their brightness values. If pixels on the upper layer are lighter than 50% grey, colours on the lower layer are dodged. When pixels on the upper layer are darker than 50%, pixels on the lower layer are burned. The Opacity slider was left at 100% for this image.

Pin Light compares colours on both layers. Pixels on the upper layer that are lighter than 50% grey will replace darker pixels below. Pixels on the upper layer that are darker than 50% will replace lighter pixels below. The Opacity slider was left at 100% for this image.

Difference blends both layers by subtracting saturation values and applying very saturated colours to the image. The Opacity slider was left at 100% for this image.

Exclusion uses a similar process to Difference blending but with reduced contrast. The Opacity slider was left at 100% for this image.

Hue creates an effect by combining the hue of the upper layer with the luminance and saturation of the lower layer. The Opacity slider was left at 100% for this image.

Saturation combines the saturation of the upper layer with the luminance and hue of the lower layer. The Opacity slider was left at 100% for this image.

Colour blends the hue and saturation of the upper layer with the luminosity of the underlying colours. This tool can be used for colourising black and white photos. The Opacity slider was left at 100% for this image.

Luminosity combines the luminosity of the upper layer with the hue and saturation of the lower layer. The Opacity slider was set to 50% for this image.

 

This is an excerpt from  Photo Review Issue 49.

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