Techniques to delete a background from an image in photoshop

May 10, 2013
background removal

Example of a background removed from an image

Knock out, strip out, clip out backgrounds – whatever you call it, at some point you’re going to have an image where you want to remove the background. And, sometimes it can be a pain unless you know how to use some of photoshop’s tools and techniques.

Photoshop is a wonderful program that offers many different ways to achieve the same results. Some work better than others, and sometimes you have to combine techniques for the best result. My advice? Keep a level head and a lot of patience. Below is a brief overview of the more common ways to remove the background from an image.

Pen Tool:
My all time favorite for general masking is the pen tool. Nothing beats it for a smooth, exact cutout of your image from the background. The pen tool utilizes bezier curves as you click and drag your points and move around your image. With a little practice you’ll find yourself a pro in no time. Practice until you can make a perfect circle in just 3 points. This technique is perfect for images with hard, definitive edges.

Refine Edge:
Photoshop has replaced it’s extraction tool with the refine edge tool. This is fairly good for complicated masks. You make a general selection, then fine tune it with the refine edge. Refine edge offers many options to play with: Smooth, feather, contrast, shift edge, decontaminate colors and more. Each image will be a little different so it’s best to experiment a bit for the best results.

Channel Mask:
This is useful when you do have a complicated image to separate from the background. It’s easiest if you duplicate a channel and make an alpha mask. Adjust your alpha mask so it’s a solid black & white of the areas you wish to preserve. You simply make your adjusted alpha mask into a selection, select your rob (or cmyk) channel and create a new layer with your selection. This technique is great for fine lines you wish to preserve.

Magnetic Lasso:
Many beginners choose to use this because it’s easy to master, and does a decent job of selecting the area to be deleted from the background. It works best when there is a good contrast between the edge of the object and background. The magnetic lasso tool will automatically snap to the edge of similar colors and has frequency controls to help control how the edge is detected.

Lasso:
Perhaps you’ll just wish to draw freehand selections. Generally this takes good hand / eye / mouse coordination, but still be a viable option for deleting a background, or small portion of the background. It’s not normally used for very precise or large selections.

Magic Wand Tool:
This is another one that works well if there is a good separation between the background and main subject you’re trying to knock out. The tool has several settings you can play with for optimum results.

Background Eraser:
Even easier than the lasso, simply erase what you do not wish to show. You can just start erasing, or you can sample the background color as you erase to erase only pixels of similar color to what you’ve selected.

Combination of Techniques:
Sometimes none of the above tools will work alone. This is when you start combining techniques to achieve the best result. For example, if you have an image of a person on a complicated background (leaves, other people, etc) you may wish to erase part of it, use the pen tool to get a solid separation of the clothing area, and use the refine edge to grab the hair. Perhaps you miss a bit – then you use the lasso to grab that small area, etc., etc.

As you can see there is no one right or wrong way to separate a subject or object from the background. Photoshop gives it’s users many tools to achieve a specific task.