Creating Visual Effects - Replace a Background with Something Else

(Page 3 of 11 )

Before You Begin

• About Tools and Tool Options

See Also

• Erase Part of a Layer
• Remove Unwanted Objects from an Image

One of the simplest special-effects tricks you can pull off is to remove the background from around a subject and replace it with something else. For example, are you the only one who didn't make it to a recent family reunion? There's no reason you have to remember that fact forever—just use the Background Eraser to remove the background from a recent photo of yourself and then replace the background with the reunion photo. After a few minutes' work, you'll be partying with your cousins. Of course, there are legitimate reasons for replacing an image background as well—if you have a photo of someone in a black suit against a dark background, you won't be able to do much using PSP's contrast controls to separate them visually. Better to select the subject and place him or her on a lighter background that provides more contrast.

Erasing the background from around a subject has typically been a time-consuming task, but Paint Shop Pro's new Background Eraser has some special options to help you do the job quickly. To control which pixels get erased, adjust the Tolerance and Sampling options: Typically Auto Tolerance (which adjusts the tolerance level on the fly, based on the color of the pixels you brush over) is your best bet; however you can set a Tolerance value manually if you like. Of the Sampling options, Continuous (which causes the brush to sample pixels located at the center of the brush tip at each step and erase matching pixels) is typically your best bet, although you might use Once (which samples pixels only when you first click), ForeSwatch, or BackSwatch (which erases pixels that match the current foreground or background color) occasionally.

---

Note - Normally, the Limits value is set to Contiguous, which erases matching pixels under the brush tip only if they touch the center pixel. This might make it difficult to erase the background if it peeks through your subject (as the sky does through tree branches). Use Discontiguous in such a case. Use Find Edges to stop the erasure of matching pixels at any "edges."

---

1. Select Background Eraser Tool

   On the Tools toolbar, click the Background Eraser tool. (If it's not displayed, click the arrow on the Eraser tool and select Background Eraser.)

2. Set Options

   On the Tool Options palette, select the brush tip, Size, Hardness, Tolerance, Limits, Sampling, and other options you want. If you lower the Opacity, you'll only partially erase pixels as you drag over them (in other words, they'll become partially transparent).

   ---

   Tip - To include pixels from lower layers in the sample, enable the Sample merged check box. Enable the Ignore lightness check box to ignore differences in brightness and instead erase pixels of similar saturation.

   ---

3. Drag to Erase

   In the Layer palette, change to the layer you want to erase—if you want to erase pixels from the Background layer, you must promote it first by selecting Layers, Promote Background Layer. Click and drag with the Background Eraser tool. To "unerase" an area (restore pixels you erased earlier), drag with the right mouse button.

   ---

   Tip - To prevent yourself from accidentally erasing something you don't want to, make a selection first—the Background Eraser erases only the pixels within the selection.

   ---

4. Insert New Background if Desired

   After erasing the background from around a subject, you can replace it with something else if you like, or leave the transparent pixels so that you can place the image against a Web page background or on your Windows desktop. To replace the background, simply open the image you want to use as the background, click Copy, and then paste the new background to a new layer in the original image by selecting Edit, Paste, Paste As New Layer. In the Layer palette, drag this layer below the layer whose background you've erased. Resize and reposition the new layer if needed using the Deform tool.

5. View the Result

   This image was a case of "had to do." My sister Pat let me borrow a wonderful image of her pushing a walker around our driveway, and when I looked at it, I couldn't help but imagine her racing someplace "sportier." What better background could I use than a photograph of the track out at the Indianapolis Motor Speedway? When I pasted the track background image onto a new layer in the scooter image, it automatically turned grayscale, so I didn't have to fuss with converting it first. (This is actually a picture of turn 1 at IMS, which veers to the left as you're coming into it, but because I wanted to show the turn behind Pat, I used the Mirror command to flip it vertically so that it looks like she is coming out of the turn and driving in the same direction the Indy cars do.)

Figure 15.3

This chapter is from Paint Shop Pro 8, by Jennifer Fulton, (Sams, 2004, ISBN: 0672323893). Check it out at your favorite bookstore today. Buy this book now.

Next: Create a Soft Focus Effect >>
 

More Graphic Design Articles
More By Sams Publishing

Comments On: Creating Visual Effects

>>> Be the FIRST to comment on this article!