Introduction to Photoshop
Brian AtkinsFebruary 27, 1997
- What is Photoshop?
- Photoshop is a software package from
Adobe Systems, Inc., which
may be used to create and manipulate digital images. It is simple
enough to be useful to someone with very little experience using
computers. However, it is also flexible and sophisticated, which
makes it useful to professionals in the graphic arts industry.
In this short course, we will look at some of the most basic things you can do with Photoshop. In particular, we will learn how to
- run Photoshop;
- create a new image;
- display an image;
- save an image;
- change the format of an image file (e.g., TIFF, GIF, JPEG);
- zoom in to a particular region of an image;
- crop an image; and
- add text to an image.
To my knowledge, there are no site licenses which provide Photoshop to the general Purdue public. I think that for the most part, it is bought by individual groups as needed. For more information about availability, talk to your site specialist.
- What type of system should you have to run Photoshop?
- Photoshop is available for the Macintosh, for PCs, and for
UNIX-based machines. If you are a student, you can get an
"Educational Version." The Educational Version is less expensive,
and it has the same capability as the non-Eductaional Version!
As an example, here are the recommended system requirements for the Educational Version for PCs, available for $279 at the University Book Store. Minimum allowable system requirements are included in parentheses.
- Pentium/Pentium Pro (i486 or faster processor)
- Windows 95, Windows NT (Windows 3.1 w/ DOS 5.0)
- 32 Mb RAM (at least 16 Mb RAM)
- Windows 95, Windows NT (Windows 3.1 w/ DOS 5.0)
- 25 Mb of free hard-disk
- 24-bit color display adapter (256-color display adapter)
Running Photoshop
For Photoshop to run, it has to be installed on your computer. To do this, follow the instructions in the Photoshop manual.To start Photoshop, all you have to do is double-click the Photoshop icon. On a Macintosh, the Photoshop icon may be in the Apple pull-down menu, which is in the upper-left-hand corner of the screen. If it's not there, go into the Applications folder, and look for the "Adobe Photoshop" folder. This folder should contain the Photoshop icon.
The Toolbox
When Photoshop is running, there will be a box, called the Toolbox, on the screen. It contains various icons which represent functions for working with images. There may be other windows open too. You will learn their functions as you gain more experience with Photoshop.
Foreground and background colors
Near the bottom of the Toolbox, there are two squares which contain colors. You will notice that one of the squares (the one on the left) partially covers the other square.
The square on top is called the "foreground color." The square which is partially covered by the foreground color is called the "background color." Photoshop will use the foreground color when you are adding text, lines, boxes, circles, etc. To swap the foreground/background color pair, just click on the arrow which is pointing at both of them. The background color has other reasons for existing; but for now, you can just think of it as another color which you may want to use now and then.
Creating an image
To create a new image, execute the "File:New..." pull-down command. A dialog box will open up. Use the box to tell Photoshop what size to make the image, and what background color to give it. Then click "OK." Then Photoshop will display the new image on the screen. After this, you can manipulate the image however you like.
Displaying an image
You can display an image while Photoshop is running. To do this, use the pull-down command, "File:Open..." . Once you do this, a window will appear, so that you can identify the image which you wish to display. Use this window to go to the directory where the image is stored. Then select the image, and click "Open."
Usually, Photoshop will able to identify image files. But sometimes Photoshop may not recognize them. Be sure that the image has been stored in a format which Photoshop understands. The list of these file formats includes TIFF, JPEG, and PICT.
Saving an image
When you are done manipulating your image, you will want to save it. To do this, you can do one of two things.
- Use the "File:Save" pull-down command to save the image under its original file name, in its original file format This will overwrite the original file. Be sure you want this before selecting "File:Save" !
- Use the "File:Save As..." pull-down command to save the image under a new name, in a new file format. In this case, a dialog box will open up, so that you can specify the new file name and file format. Once you have done these things, click the "Save" button.
Changing the format of an image file
To change the format of an image file, you must first Open it in Photoshop using the pull-down command "File:Open..." . Then execute the pull-down command "File:Save As..." . When the dialog box appears, specify the desired file format. Then click the "Save" button.
Zooming in and out
Sometimes you will want to zoom in to get a better look at a particular region of an image; and on other occasions, you will want to zoom out in order to get a broader perspective. To zoom in, execute the "Window:Zoom In" pull-down command. To zoom out, use the "Window:Zoom Out" pull-down command.
Zooming in and out can also be done with the magnifying glass tool. To use it, click on the magnifying glass icon in the Toolbox. When there is a "+" in the magnifying glass, clicking in an image will zoom in. When there is a "-" in the magnifying glass, clicking will zoom out.
The default operation for the magnifying-glass tool is to zoom in. On a Macintosh, you can press the "option" key to enable the zoom-out function. When this is done, you will see that the "+" in the magnifying glass changes to a "-", in accordance with the symbolic convention.
When you zoom in, the image will appear larger on the screen. If the image is bigger than the screen, you may have to use the scroll bars to look at different parts of the image.
Selecting regions of an image
Very often, you will only want to look at or modify isolated parts of an image, as opposed to looking at or modifying the whole image. In order to specify a region of an image, you must use a selection tool. In Photoshop, regions that have been selected are always outlined by a hypnotizing black-and-white perimeter, called a "marquee." To make a marquee (that is, to make a selection), you can use either of the "marquee" or "lasso" tools, which are available in the Toolbox.
The marquee tool may be used to select rectangular regions. After clicking on the marquee icon, just click-and-drag the rectangular shape that you want to select. To make a square selection, use the marquee function while holding down the shift key.
The lasso tool is used to make selections of arbitrary shape. The lasso icon is also in the Toolbox. It looks like a lasso. It is generally used to identify regions of non-rectangular shape. Probably the best way to learn about the lasso it to play around with it. Just select it, go into the open image, and click-and-drag for a few minutes.
Cropping an image
You can use Photoshop to cut a small piece out of an image. This is called cropping. You can only crop an image to rectangular dimensions.
It is important to know that cropping an image actually throws information away. (You keep the part you cropped, but you will lose the rest of the image.) So if you want to save the cropped image, it is safest to save it under a new name. Be careful not to replace the complete image file with the cropped image file!
One way to crop an image is to first select the desired rectangular region of the image using the marquee tool. Then execute the "Edit:Crop" pull-down menu command. (For more on selecting using the marquee tool, see the section entitled "Selecting regions of an image," above.)
Another way to crop is to use the crop tool, which is available in the Toolbox. To do this, click on the crop tool, and click-and-drag the desired rectangular region. Then when the mouse-cursor is in the selected region, click the mouse button.
Adding text to an image
To add text to an image, you can use the text tool in the Toolbox. There are two important things you should know about adding text to an image using Photoshop.
- Once you have added the text, it is no longer regarded as a "text" object. This means that it can't be selected as "text."
- Text is always added in the foreground color.
To add text, click on the "T" icon in the Toolbox. Then go into the image with the mouse-cursor, and click in the approximate location where you would like to text to be. A dialog box will open up. Using this box, you must
- type the desired text into the big, blank box; and
- specify the desired font, size, style, and alignment.
Once this is done, click the "OK" button in the dialog box. After you have done this, a selected region will appear in the image. You will notice that the selected region is the exact shape of the text which you specified in the dialog box. You can move it around the image by dragging it with the mouse. To set the text into the image, move the mouse away from the selection (but in the image), and click the mouse button. From here on out, it is an integral part of the image, and will not be observed as a "text" object.