Extracting a Model From a Background Using Channels in Photoshop

Working with Channels can help you easily extract models from a background. This tutorial will teach you how.

When looking for a stock image of a model to use in an advertisement or publication, it is likely that once you find the perfect image, the image background isn't quite suitable for your design. That is when knowing how to extract the model from the background to use in your design comes in handy.

One common hurdle during the extraction process is the model's hair. But using the Channels Palette as an aid can make the entire process much easier. When using a channel to make a selection, there are some fundamentals to understand.

Just like a layer mask, everything that is black will not be seen and therefore won’t be part of the selection.  Everything that is white will be seen and will be part of the selection. Each shade of gray will determine the amount of transparency that is applied to that region of the selection. The darker the shade, the more transparent that part of the selection will be. So in this image, the goal will be to turn the background completely white and the model completely black, then simply inverse the colors. A little tip: the ends of the hair should be kept in gray tones to help blend the hair with the new background.



To make the process easier, use an image of a model on a neutral background and work with it in the RGB color mode. Open the Channels Palette. Select each individual channel until you find the one that gives you the most contrast between the background and your model. In this image, the Blue Channel gives the most contrast. Drag the selected channel down to the Create new channel icon to make a duplicate of that channel.



Start by going to Image > Adjustments > Levels to apply a Levels adjustment to your copied Channel. Using the white slider, adjust it accordingly so the background is completely white. Next, go to Image > Apply Image to darken the model. This function simulates duplicating the current layer, changing the blend mode of the new layer and then merging the two layers together. The beauty of Apply Image is it performs all that in one function.

In this example, since we want the model to become darker, we will choose Multiply as the blend mode. Since the background is already 100% white, it will not be affected by the Multiply blend mode. In your own image, you may need to experiment and find the blend mode that gives you the best results.



To create more contrast between the hair and the background, use the Burn and Dodge tools to go over the hair areas. Change the exposure of the Burn and Dodge tools to 5 – 10% to make subtle changes. Keep some gray tones at the ends of the hair. This will help to better blend the hair onto its new background. If there are any other gray areas around the edges of the model, use the Burn tool to darken the edges until a good contrast is achieved.



At this point, select the Brush Tool, set the foreground color to black and paint in the inside of the model where gray and white tones still exist to make the model completely black. Stay away from the edges of the hair; let the previous Burn Tool adjustments do their work in those areas.



With the copied channel still active, hold down Ctrl+I or Cmd+I. This will render an inverse of the image, turning all the white pixels to black and vice versa. Then hold down Ctrl or Cmd while clicking on the thumbnail of the channel, and a selection will be made. Click on the RGB channel to go back to the color view of your image and then go to your Layers Palette. Hold down Ctrl+J or Cmd+J to copy your selection onto its own layer. Now you will have a perfectly extracted model with great details in the hair. You can then copy that layer into your layout.