| 9/21/05
Resolution:
Screen Resolution is 72 dpi
Always ask yourself:
At what resolution should I scan my image?
At what resolution should I print my image?
Most ink jet printers make the best print at 300 dpi
Types of printers:
Standards: 300 dpi
Ink Jet (common to home-users)
Laser (common to places like Kinkos)
Wax Printer (common to places like Kinkos)
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Standards: vary
4-color press (common to magazine publishing, etc.)
Dye-Sublimation (common to photographers)
Iris Prints (are similar to ink jets, higher quality and found at service
bureaus)
LPI = Lines Per Inch; LPI = 1/2 DPI
Printing for a newspaper: 150 LPI = 75 DPI
Printing for a magazine: 600 LPI, 800 LPI, 1200 LPI,...
Color Modes:
RGB (most scanners and ink jet printers will use this mode)
CMYK
Grayscale
Index
Lab
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Notes for scanning a photograph:
1. Place the image on the scanner aligned with the left
or right edge but not near the top or bottom of the scanner. If you are
scanning something that makes the lid stay ajar, put a dark cloth around
the lid so that light doesn't leak out.
2. From PhotoShop, access the scanner using
File--Import--ScanGear
3. Hit the Preview button in ScanGear software (the PhotoShop
tools on the left side of your screen will not work in the scanner software).
4. Wait for a while as the lamp warms, etc.
5. Select only the area you want to actually scan.
6. Set the scale and the resolution, measured in DPI.
Also select "Color", "Grayscale", or "Black and
White" (for line drawings).
7. Hit the "Scan" button (top middle area).
8. Wait until your image appears behind the ScanGear
software in PhotoShop. Close the ScanGear software and then SAVE your
file from PhotoShop.
9. You can save the file to the desktop and then either
drag it into the Shared Drive so that you will have access to the file
from another machine in the lab or you can save it to your Flash (jump)
drive or CD-ROM. Files on the computer attached to the scanner are often
deleted.
Notes for scanning from a magazine:
Goal: get rid of the "moire" (pronounced "More-ray")
pattern
1. Scan the magazine image at twice the resolution that
you would normally use
2. In PhotoShop, Save the image as a PSD file
3. Use Filter--Noise (submenu)--Despeckle
4. Image--Image Size Dialog Box
5. With "Resample Image" activated, type in half of the resolution.
Notice that your file size will become much smaller.
6. View the file at 100% and if you need to further despeckle the image,
do so with the Filter--Noise--Despeckle.
(Hint: command-F will apply the last filter that you used. In this case,
it is probably the despeckle filter)
7. SAVE (command-S)
Selections:
Adding/Subtracting:
With any selection tool, SHIFT (+) while selecting will add to the selection
(you must have made a selection, no matter how bad it is, at first
in order to add to it or subtract from it). OPTION (-) while selecting
will subtract from a selected area.
Inverse the Selection
Under the Select Menu: Inverse or command-shift-I
This will select the opposite of what you have selected. Remember when
I selected the white area around the flower during our lab time, then
I went to Select: Inverse--this selected just the flower.
Tools and Options:
Marquee tool:
Selects a rectangle or ellipse
Hold down SHIFT to constrain the proportions (ie. to make a perfect circle
or square selection).
Feathering will create a soft edge near the border of the selection (it
will look fuzzy or blurry if you select an image with feathering and
then move it somewhere else).
While you are drawing the selection, hold down SPACE BAR to move the
selected area around on the screen--the trick is to NOT let go of the
mouse until you are completely finished with the selection.
Magic Wand:
Selects an area by pixel data (color).
Tolerance: tells the computer how many "like" pixels to select.
A higher tolerance means a larger selected area.
Lasso:
Selects an area by freehand drawing
Magic Lasso: tries to "find the edges" of the area you are
selecting. This one can get you into a big mess of "selected areas".
If you get lost, double-click and then deselect. Start again. In order
to complete the selection, you have to close the path (find the O where
you started the selection). If the magnetic lasso isn't "finding
the edges" for you, you can force it to place down anchor points
by clicking the mouse.
RGB
If you scanned in black/white or grayscale, make sure the image is in
RGB mode in order to add any color to it. Use Image: Mode: RGB
In the Images Menu, see Adjustments for methods of colorizing an image.
In class we looked at Invert (command + I) and Hue/Saturation (command
+ U).
Key Commands we learned in class:
Command = Apple (they're the same key)
On a PC Command or Apple = "Control"
On a PC Option = "Alt"
Space Bar: yields the Hand tool, which enables us to move the image
around within the file. It doesn't actually MOVE the image (that's the
move tool), but it changes our view.
Space Bar + Command = Zoom In
Space Bar + Command + Option = Zoom Out
Shift + Selection Tool = Add to the selection
Option + Selection Tool = Subtract from the selection
Option + Move Tool = Make a duplicate (then look in your layer palette)
Command + H = Hide the selection edges
Command + D = Deselect the selection
Command + S = Save
With a selection in progress, + Space Bar = Move the selection
Option + Drag a selection = drag from the center point
HOMEWORK
Utopian Family Assignment
NEXT WEEK
In class we will review making selections, saving
and loading selections, and complete a tutorial on using the layer palette.
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