Enhancing Digital Images: Some Basics

STEM Earth Central

August, 2005

Mort Sternheim, Holly Hargraves

Adobe Photoshop Elements 3.0 Many, many features Windows and Mac versions (some

differences) Academic price about $53 (~$100 list)

(govconnection.com, 800-998-0009) Simpler, easier to use, cheaper than Adobe

Photoshop (~$600 list ) Free 30 day trial download from adobe.com

References and Help

Photoshop Elements 3.0 for Dummies Excellent $21.99 list, $15.39 from Amazon.com

Elements manual < Help Help has search options, tutorials

How to palette in program

Today Basics

Adjusting brightness, contrast (Levels) Adjust color Quick Fix Cropping

Redeye Reducing file sizes for PowerPoint, web,

email Using Layers to make labels

Elements components View and organize photos

Tags, collections, search by date …. Quickly fix photos (Quick Fix)

Automated, menus Edit and enhance photos (Standard Edit)

More control, options, tools, …. Make photo creation

Web gallery, Slide show, Card, postcard, calendar, VCD, …

Getting Started Double click on the Photoshop Elements icon

to start the program On the Welcome Screen, select Edit and

Enhance Photos Use File Open, go to the Desktop, and

then to SEC_Photos Double click on Alan.jpg to open that file. On the menu bar (top of screen), click on

Window, and then on Undo History. This lets you track and undo changes

Adjusting Brightness and Contrast Useful for nearly every photo! On the menu bar select

Enhance Adjust Lighting Levels You will get a screen with a levels histogram and

three sliders just below it. Drag the rightmost slider to the left until it is under

the end of the graph. (Brighter whites) Drag the leftmost slider a bit to the right. (Darker

grays.) Drag the center slider to the right or left to choose

the best midtones. Click OK.

Levels

Levels Histogram for Alan.jpg

Levels, cont.

Use the Undo History palette to undo/redo Levels effects

Try this exercise with Ilka.jpg To see a major improvement with Levels, try

ibis.jpg Try Levels on underexposed photos such as

Kathy.jpg or Oval Window.jpg

Adjusting Color

Try Enhance Adjust Color Color Variations with one of these images.

Experiment with some other Adjust Color options.

Quick Fix

Fast, easy, somewhat limited Open Ilka1.jpg Select Quick fix. Note the Undo and Redo

buttons that let you retrace your steps. Note menu options for General Fixes,

Lighting, Color. These are not as powerful as the equivalent individual menu options, but easy to use and experiment with.

Cropping Trim off unwanted stuff; zoom in on birds, etc. Easiest way is with the Crop Tool. Open gps.jpg On Toolbox, click on Crop Tool Click at one corner of area you want to keep,

drag to opposite corner, release. When you are satisfied, hit click on the check

mark (commit) on the right side of the Options bar. Or, to start over, click on the cancel icon.

Adjusting crop boundaries

You can drag any “handle” to modify that part of the boundary. Shift-drag on a corner handle constrains the proportions.

If you position the cursor inside the box, you can drag the whole box to a new location.

If you position the cursor outside the box, you can drag and rotate the box.

Cropping to specific sizes, resolutions Handy for preserving aspect rations, and for

cropping and resizing to desired print formats. In the Options bar, note the Width, Height,

Resolution boxes. Enter 6, 4, 300. (More on resolution later.)

Click on a corner of the desired box and drag. The resulting box will be have 6/4 proportions.

When you click on the check, the image will have 6” x 4” dimensions, and 300 pixels per inch.

Fixing Red Eye

Fixing Redeye Open smile.jpg Use the Zoom Tool to enlarge her eyes. Select the Red Eye Brush in the Toolbox.

Click in the red area of an eye. This should remove the red eye,

(If you want to adjust the effect, vary the pupil size and darken amount in the Options bar. This is seldom needed.)

Open redeyegirls.jpg and fix their redeye

Pixels and Displays

Screen images are made up of tiny squares called pixels (picture element).

Pixels are usually 1/72 inch across. Today most people use 800 x 600 or 1024 x

768 pixel displays, or < 1 million pixels How large a given image appears depends

on the screen settings! An image 800 pixels by 600 will fill the 800 x 600 display but not the 1024 x 768 display.

Downsizing Images

Most people have displays with less than 1 Megapixel and can’t see a larger image all at once

Downsize pictures for PowerPoint, the web, or email, usually to 0.5 Megapixels or less.

This makes it faster to load (or download) Exception: You expect someone to make

large prints from the image.

Why buy a 4 or 8 Megapixel camera? You can’t see all those pixels at once on a

screen. But, you can make use of them for zooming,

cropping. You can also make larger, better prints with

more pixels.

Checking Image Sizes

Open Brie.jpg in Standard Edit or Quick Fix Select Image Resize Image Size You will see the following screen

Image size dataWidth: 2272 pixels (7.573 inches )

Height: 1704 pixels (5.68 inches)

Channels: 3 (RGB)

Resolution: 300 pixels/inch

• Numbers in inches (7.573, 5.68) define the size if the photo is printed.

• The width and height in pixels (2272 x 1704) define how it will fit on a screen

• The resolution (pixels per inch or ppi) how good the print will be; it means nothing for onscreen viewing.

• Channels (RGB) color, not grayscale

Changing Image Size for Screen Use Select Image Resize Image Size Make sure Constrained Proportions is

checked For Width, enter 800 Height should automatically change to 600. Note the file size is now 1.37M (was 11.1M) Click on OK Note: You can resize a batch of files all at

once using File Process Multiple Files

Saving the Image File

Select File Save As. For File name, enter Brie1.jpg to avoid overwriting the original image. (.jpg format is the best image format for photos in most cases. It compresses the file while preserving nearly all the details.)

Click on Save. In the next screen, select High Quality and then OK. (Note the image size is now 87k. The original Brie.jpg file size was 844k.)

Resolution and Printing

For good ink jet photos, you need at least 150 pixels per inch (ppi)

200-300 ppi is better For 8 x 10.66 print,

150 x 150 x 8 x 10.66 = 1.9 million Thus an 8 x 10 requires a 2 Megapixel image or

better for good results. Set print size with Image Resize Image Size,

changing Document Size Width, Height Or, use File Print or File Print Multiple

Photos. (Picture packages, contact sheets …)

Layers

Like sheets of transparent plastic on an overhead projector.

Work more easily on one element of image – edit one layer at a time

Combine, copy images Create text layers with

labels, etc.

Adding labels with text layers Open 1ibis.jpg Click on Window and on Layers to display the

Layers palette Right click on the Text tool in the toolbar Select horizontal type Position the cursor somewhere near its head Type the word “head”

Changing the appearance of text Use the move tool to position the label Click on the Text tool again Change the font, font size, and color of “head”

using boxes in the option bar Use the icon next to the color option to warp

the text Click the last icon to change the text

orientation

More labels

Click on the Text tool. Put you cursor near a leg and type “leg”

Again, play with this label – move it, format it, etc.

You can select the “active layer” by clicking on the appropriate layer in the layers palette. The active layer is indicated by a paintbrush in the second column and a blue field to the right.