The “Background Eraser” trick for line-drawings in Photoshop

Some months ago, I learned a nifty little trick in Photoshop which allows you to take a scanned drawing and remove all of the background while keeping the drawing. This method is done without any use of the magic wand tool, the background erase tool, or any other messy manual erasing tool. “But how,” you ask. It’s simple. Just follow along below:

Before we do anything, we have to, of course, get our image into Photoshop. So scan your beautiful line-drawing, and open it in Photoshop. Once this is completed, go to step 1.

Step 1: Change image mode to Grayscale, and make a copy of the background layer

Go to the main menu and select: Image > Mode > Grayscale. It will ask you if you want to “Discard Color Information?” Have no fear! Click “discard.” (Note: if it first asks you if you want to flatten all layers, this is because you had more than one layer, so go ahead and hit “OK”) Now in the Layers palette, drag your background layer down to the icon and drop it on top of it. This will create a copy of the background layer called “Background copy.”

Step 2: Create a Selection out of the line-drawing

Select all of your new copy layer. You can do this by simply holding “command” (control on the PC) and hitting “A” for “all.” Now, you should see “dancing ants” around the border of your image. In the main menu, select: Select > Load Selection. You should get the following dialogue box:

If it says, “Background Gray” —as it says above—in the “Channel” dropdown menu, then you’re on the right track! If not, check your steps and make sure that you did everything in the right order. Your “mode” may be the culprit. Make sure it’s set to “Grayscale.”

Once you hit “OK” you will now notice that the “dancing ants” are surrounding your line-drawing now, as well. Isn’t that awesome? Oh yeah, it’s way awesome!

Now, all that you really have is a simple selection like any other. Anything that you can do with a normal selection, you can do here. So, Let’s first delete the background . . .

Step 3: Isolating the line-drawing

In the Layers palette, highlight the “Background” layer. Now hit the little trash can icon at the bottom to delete it.

OK, now make sure that the “Background copy” layer is still selected in the Layers palette and hit delete. You should see the background disappear and, in its place, the checkered background indicating “transparent” or “lack of any pixels.”

Now, if we want to do anything to our line-drawing, we have to invert the selection. Do this by going to the main menu, selecting: Select > Inverse, or simply hold “shift,” “command” and hit “I”. Once this is done, anything that we do will effect the line-drawing part. Go ahead and make sure that your foreground color is black or at least really dark. Now hold “command” and click the large “delete” button (backspace on the PC). This will fill the selected area with the foreground color; the reason that I had you check to make sure it was a dark color.

Finallly, hold “command” and hit “D” to “deselect” everything, and there you should see just your line-drawing. If you want a white background, simply create a new Layer in the Layers palette, move it below the line-drawing layer, and fill it with “white” either by our little “foreground color” fill trick, or by simply using the paint bucket tool. Now, you have a white background! If you need to add any color to this image, don’t forget to change the color mode back to “RGB” or any other color profile that you wish (CMYK, etc)