Introduction to Adobe Photoshop

Adobe Photoshop, has changed the face of editorial and advertising design and raised the bar for professionals in every discipline that incorporates photography and design. Take a trip to the library and look at graphic design, photography and advertising from 25 years ago and compare it to anything you find in a magazine today, and I guarantee that the difference will be astounding. Whether you are interested in graphic design, printing, illustration, animation, film, broadcast television, multimedia, web design, or e-commerce, Adobe Photoshop is a basic must-know application and is used in each and every one of these disciplines. Photoshop is used for a variety of photographic, typographic and graphic design techniques.

What is it?

Adobe Photoshop is a raster program, and uses a bitmap format which renders images pixel by pixel to a variety of output devices. Due to the nature of Photoshop's raster technology, it is the perfect tool of choice for working with photographic images because of its ability to make global or selective color changes.

While Adobe Photoshop is a very complex and powerful software application, the way it operates is actually quite straightforward. It is a tool that can be used by a beginner with just a few minutes training, or by an advanced user performing very complex operations. The essential Photoshop requires that you understand how to use the copy / paste process and that you understand the concept of selecting before applying changes to a given element within a document.

Several scanner manufacturers give away a watered down version of Adobe Photoshop with each scanner they sell, while most scanner manufacturers include "plug-ins" for their scanning software which work in conjunction with Photoshop.

Photoshop's wide variety of brush-like tools also make it a good choice for creating images that use illustration and airbrush techniques, patterns and textures, and collages that take advantage of the program's ability to create transparencies using both color and texture. Photoshop's unique tool set has spawned a new way of imaging, one that photographers, artists and designers are learning, enjoying and sharing with a new generation of creatives.

The new document dialog

Before beginning any new image, you'll need to set up the specifications of the new image in the "new document" dialog box. You can name the file now, or wait until you save the file. I like to wait, because if I name it when setting up the document, I sometimes forget that I have not yet saved the file. I know when I see "untitled" in the title bar that I still need to save the file. So, I recommend waiting until you save to name the document.
The New Document dialog box is where you enter the starting size of your document (it can be changed later by increasing or decreasing the canvas size), the resolution, the color mode, and the contents, which controls whether the documents starts out as transparent or opaque. The moment layers are added to a document that begins with "white" contents, you have introduced the ability to acheive transparency.

INTERPOLATION

Interpolation is the process of determining new pixel data when an image is resized, has its resolution changed, or has had other transformation performed.

Nearest neighbor - this is the fastest method of determining the new pixel data. The software looks at the nearest pixel for color information and will not add color data that it doesn't find present nearby. While not usually preferred, this may work best on files that are saved in the "Indexed Color" mode.

Bilinear - the software analyzes data from a small sampling and based on the information in those pixels, determines the new pixel data.

Bicubic - (slowest and usually the preferred and most accurate method) this method takes the longest because it analyzes the widest range of data, gathering information about the pixels inside and outside of the area to be transformed.

Image Size

You'll need to enter the width and height of the new document. Don't worry if you are not positive about the dimensions--you can always change them later. You'll have the choice to enter the size in pixels, inches, points, picas, centimeters or columns. Photoshop lets you change the unit of measurement at any time during your work session. Notice the relationship between the height and width, the resolution and the "image size:" in kilobytes or megabytes. The amount of disk space an image occupies is directly related to its height, width, resolution and mode. That's one reason these specifications are grouped together in the box labeled image size.

Resolution should not be changed once you have created the document. You should determine the appropriate resolution for your document when you create the new image file. It is never a good idea to increase the resolution later. You can decrease it later, if necessary, however it is not recommended. Whenever you increase or decrease resolution on an existing image, the program has to decide the position and color of the new pixels by a process called interpolation, and you run the risk of degrading the image quality.

Mode

Bitmap - Choose this if you want to create monochrome line art, consisting of only a single value, black on white or white on black with no shades of gray. This is the default scan mode for line art.

Grayscale - Use this if the image you are creating will be printed using a single color ink but has more than one value, or shade. This is the default scan mode for scanning grayscale (256 gray levels)

RGB - Begin with this mode if you are creating a "full color" or multi-color image. Work in this mode for images designed for the internet or until you are ready to prepare the image for a page layout program, and / or print.

CMYK - Work in this mode if you want to create an image which will end up on the printing press. Because many filters are disabled in while operating in this mode, it is not uncommon to begin the image in RGB and convert to CMYK when you are ready to output to your page layout program. Once you have converted an image from RGB to CMYK, you cannot make further mode conversions without corrupting the separation data.

Lab - Use this if you will be burning a CD or creating image data that must maintain its color conversion integrity on all platforms and all monitors. Lab color is used primarily for high end distribution of original and stock photo CD images.

 

Exercise #1 Create a Mask

Masks are the very heart of Photoshop. You will be creating some of your own masks in this exercise in order to understand the characteristics and behaviors of a mask. This exercise is designed to familiarize you with the following:

1. Begin the exercise by creating a new document. Size = 5" x 5", Resolution = 72 ppi, Mode = grayscale, Contents = white. See the "new document" dialog box Click okay, and be sure that your foreground / background color swatches are set to black and white, the default colors. Press the letter "D" on the keyboard to reset the colors to default black foreground, white background.

2. Select the Rectangle Marquee tool. Click on it with the mouse, or press the letter "M" on the keyboard to activate the Marquee tool.

3. Move your cursor into the image area, and click and drag on a diagonal to create a rectangular marquee. To constrain the marquee to a perfect square, press the "shift" key while dragging.

A document that is set up as a white document in the "new document" dialog has no Layers, so when you use the eraser, the computer changes the erased pixels to the background color. If you use the eraser on a document set up with transparent contents the eraser clears the pixels to transparent.

 

 

 

4. Select the Brush from the tool palette by clicking on it, or press the letter "B" on the keyboard. The brush options appear just under the menu bar. Click on the arrow to the right of the "Brush:"and choose any of the large brushes in the top row by clicking on it. Beginning at the far left side of the image window, click and drag to the right, crossing over the selected pixels, and finish by dragging to the right edge of the window.

5. Next, in the brushes palette, choose the brush in the second row, directly below the first brush you chose and repeat the procedure in step 4 above.

6. Deselect by pressing Command-D, or go to the Select Menu > Deselect. Let's take look at the Eraser Tool. Click on the eraser in the tool palette to select it, or press the letter "E" on the keyboard. The options for controlling the behavior of the eraser appear just under the menu bar. The behavior of the Eraser can be customized like a Paintbrush, Airbrush, pencil or block. Experiment with all the styles and return your canvas to white.

7. You'll be saving your file, but before you do, let's set up the preferences for Saving Files. Go to Preferences > Saving FilesŠ Preferences allow the user to make specific determinations concerning image previews, the file extension, and file compatibility. It's a good idea to get into the habit of Appending the File Extension, which means that when you save the file, Photoshop will automatically add the period and the three-letter file extension describing the format in which the file is saved.

8. Save your file by going to the File Menu > Save. Choose the appropriate format. We'll use the Photoshop format. In this case, the file extension is ".psd."
This image uses the standard paintbrush. Notice the edges of the stroke. Can you see the difference between the standard brush and the feathered brush in the image to the right? Observe how the brushes interact with the edge of the selection marquee. What effect does the selection have on the image? Describe the ways in which a selection behaves like a mask. Which pixels are editable and which pixels are masked?

 

The "Save" diaog allows you to choose the file format for the file you are saving. If your file contains more than one layer, be sure to check the "layer" box in the save options, which is hidden under the pop-up format options.