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Exploring Photoshop 4:
Cutting and Superimposing

Module D14h

* About this document... * Audience and Objectives * 
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Contents

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Overview

One of the more frequent and amusing tasks in graphics work is to combine material from one photograph into another. This can be done in order to deceive people, but we won't attempt that! We'll just use the technique to produce an interesting effect.

For the first photograph, we'll use a picture of an Indonesian dancer performing at WCC's 2000 International Festival, on the stage of Towsley Auditorium. We'll remove the image from the stage and place it on the lawn of WCC's park, in front of the Liberal Arts Building.

The resulting image of the dancer on the lawn should be saved in Photoshop's native format, .psd. This format is bulky, but makes later editing easy. However, the image should also be saved as a JPEG so it can be sent as an email attachment to the instructor. (For more detail on saving images in various formats for the Web, see module D23h, "Exploring Web Image Formats".

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Cutting Out a Complex Figure

  1. Open the image of the dancer (see instructions at right)
  2. If you're not familiar with the Magnetic Lasso tool, read about it in Photoshop's Help. (Search for the word Magnetic.)
  3. Pick up the Magnetic Lasso tool.
  4. Outline the dancer bit-by-bit. Be careful, but don't expect this to be perfect. It's better to include more background than to cut off parts of the dancer! (Erasing background is relatively simple, but picking up missing pieces is a bit trickier.) Hints: see box at right.
  5. To finish the outline, press the <Enter> or <Return> key on the keyboard.
  6. If the outline looks pretty good, Copy it to the clipboard (Edit...Copy on the menu or <Ctrl>c on the keyboard). If the outline is missing parts of the dancer, press <Ctrl>d to undo the selection. Repeat steps 4-6 above.

Getting the Picture

The image of the dancer is available by clicking this link: d14h_f01.jpg. The file is 303K and takes about a minute to download at 56K baud. When the picture opens in the browser window, right-click (Windows) or click-and-hold (Mac) to bring up a context menu. Choose Save Image As and put it on your disk.

Using the Magnetic Lasso

  • Start by clicking the wand at the boundary between the dancer and the background.Move slowly along the boundary, staying close to the edge.
  • Before going around a sharp curve or angle, click the mouse to establish an anchor-point. That presents the Lasso from cutting off parts that stick out (fingers, toes, etc.).
  • Select modest amounts at one time. For example, do the upper edge of one arm, circle back to the starting point, and press the <Delete> or <Backspace> key. Then do one hand, circle back, and press <Delete>. Then do the lower edge of the arm, circle back, and <Delete>. That prevents sudden slips from wiping out a lot of work.
  • Use the Eraser rather than the Magnetic Lasso when the boundary is unclear - that is, when the color in the part you want to save is similar to the background. The Magnetic Lasso can't detect the boundary when color values are similar on both sides.

 

 

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Cleaning Up and Resizing an Image

  1. Create a new Photoshop document (File...New) accepting the suggested size. However, be sure the background is Transparent. Transparent backgrounds are shown with a grey-and-white checkerboard pattern.
  2. Paste the cutout image into the new document (Edit...Paste).
  3. Choose the Eraser tool. If you're not familiar with it, use Photoshop's Help to read about it. See Erasing Hints in the box at right.
  4. In the Eraser Options bar, use either a brush or a pencil. Set the opacity to 100%, and Fade to 0 steps.
  5. Zoom in on the image so you can see individual pixels (400-800%); you can use <Ctrl>+ to zoom in and <Ctrl>- to zoom out.
  6. Work around the image erasing background bits that were missed by the Magnetic Lasso.
  7. When you've worked all the way around the image, zoom out a bit to see how it looks. Did you miss anything?
  8. Just to be safe, save the image with a name you'll recognize.
  9. Resize the image to a height of about 100 pixels. Use the Image...Resize menu to do this.

Erasing Hints:

  • When erasing large areas, consider using:
    • Magic Wand, if what you are erasing is a consistent color, different from the part of the image you want to save. When you've selected an area to erase, press the <Delete> or <Backspace> key.
    • A Marquee tool to select a large area; to erase, press <Delete> or <Backspace>.
    • Eraser with a large brush-size
  • When erasing small areas, especially close to something you want to keep:
    • Zoom in really close.
    • Choose a small brush size for the Eraser - you can get as small as one pixel.
    • Lift up the mouse button often - it makes undoing mistakes less time-consuming.
    • Position the eraser and click rather than dragging...or,
    • Drag the eraser in strokes away from the good parts.
  • Use <Ctrl>z to undo mistakes quickly.

 

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Copying and Pasting one Image into Another

  1. Copy the entire image to the clipboard by using keyboard <Ctrl>a ("select all") and then <Ctrl>c (Copy).
  2. Open the second image using the same method as the first; its name is d14h_f02.jpg. It's a picture of the WCC park lawn with the LA building in the background, about 230K and needing about 45 seconds to download with a 56K modem.
  3. Paste the figure of the dancer in from the clipboard contents.
  4. Use the Move tool to place the figure in front of the white vertical line on the lawn. (It's actually a PVC pipe sticking out of the ground.)

    5. Extra-Credit Challenge: For up to 20% extra credit, give the figure a shadow. Use the shadows of the trees to make your figure's shadow look realistic. Extra credit will be based on accuracy and realism.

  5. Save the file as .psd. This is useful in case you want to move the figure later.
  6. Save the file as .jpg. This is much more compact than psd, but flattens the image parts so you can no longer move them around relative to one another.
  7. Send an email to your instructor, attaching the finished image of the dancer on the lawn.

Audience: This is for people who have explored the basics of Photoshop and want to learn more techniques. It is designed primarily for use in a class/lab situation, with an instructor to guide students through details and demonstrate techniques.
Objectives: When you successfully complete this lesson, you will be able to...

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About this document...
Module D14h: This document is part of a modular instruction series in computer technology. For more information, see the overview or the list of modules in this series, D: Desktop Publishing and Computer Graphics. This document has been used in the following classes: INP 143/152

Author: Laurence J. Krieg
Institution: Internet Professional Department, Washtenaw Community College
History: Original: May 2000 as D21i; This revision posted Monday, 31-Aug-2009 11:47:55 EDT
Copyright © 2000, Laurence J. Krieg, Washtenaw Community College
Instructors: You may point to this file in your Web-based materials.
Students: you may make a copy for your personal use.
All other uses: contact the author, Laurence J. Krieg for permission.
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