Setting Image Attributes


Image Mode:

  1. Click Image > Mode,
  2. Click on RGB if there is NO check mark before it .This will put the color in the appropriate pallet for the web.

(RGB = red, green, blue; this pallet is used for web page production. CMYK = cyan, magenta, yellow, plack; this pallet is only used for printing.)

rgbcmyk.jpg (48983 bytes)


  1. Click Image > Image Size.
  2. A drop down menu will appear.
  3. Look on the bottom left of the menu and find two check boxes.
  4. Click to place a check in both boxes.
  5. To keep the image from being distorted, click to place a check in the constrain proportions box.
  6. Pixel Dimensions :
    1. Width box - type in the pixel width you want for your image.
    2. Height box - since you are constraining the proportions of the image, the number will change automatically
    3. Leave print size alone because you will not be printing this image.
    4. Leave resolution alone for now.
  7. File >save.
sizemenu.jpg (30428 bytes)


sizeb.jpg (28416 bytes)

Adjusting Levels

  1. Click Image > Adjust > Levels; the levels popup menu appears.
  2. Drag the menu so that you can see the menu and most of your image.
  3. Channel box should read RGB.
  4. On the bottom right is the Preview box, click on it to put a check.
  5. We will ignore the output slider, don't touch it.
  6. The image in the center of the menu should have a triangle on the left, one in the middle and one on the right.
  7. The black graph represents the amount of dark (left) and light (right) in your image.
  8. Click on the left triangle and slide it to the right; you see the effect on your image.
  9. Click on the right slider and move it to the left; look at your image.
  10. Click on the center triangle and move it left or right to fine tune your image.
  11. When the contrast is the way you want it, click OK.
  12. Click Edit > Undo Levels to return the image to the original contrast.
  13. Repeat the above steps in Image > Adjust > Levels to achieve the effect you want.
  14. Save the image File > Save .
levels.jpg (26567 bytes)


levelsb.jpg (23819 bytes)

too light                 original             too dark

Adjusting the contrast

  1. Click  on Filter > Sharpen > Unsharp Mask.
  2. Put a check in the Preview box.
  3. There are three slider bars that allow contrast adjustment.
  4. Use the radius slider first and move the triangle to 1.5 pixels.
  5. Move the Amount and Threshold sliders until you like the effect.
  6. File > save
unsharpfilter.jpg (29870 bytes)
Resizing the Canvas
  1. Click Image > Image Size and get the pixel size of the image (width and height)
  2. Click cancel
  3. Click Image > Canvas Size
  4. Look at Width, go to the black arrow, click and drag to select pixel.
  5. Repeat for the height.
  6. Enter numbers that are identical to the image size.
  7. File > Save.
sizea.jpg (30288 bytes)


The images are the same pixel size, the canvases are different.

canvasb.jpg (32288 bytes)


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These pages authored and maintained by Marcella Dawson. Revised 07/13/99. Copyright 1995 CRPC GirlTECH. All rights reserved. . Email your comments. These pages were developed through GirlTECH '96, a teacher training and student technology council program sponsored by the Center for Research on Parallel Computation (CRPC), a National Science Foundation Science and Technology Center.