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Photoshop is the leading digital image editing application. When it comes to working on descriptions or making banners, this is the ideal program to use. This article briefly goes over some of it's main functions.


Example of how layers work. Final Image

One powerful function of Photoshop is its ability to use layers. Layers are discrete sub-images within a project that overlap each other providing a greater degree of complexity, depth, and flexibility.

Using Layers

To the left is the layers palette inside of Photoshop. With it, you can see and manage your layers. If you do not see it, hit F7 or go to Window > Layers. It contains these 7 basic functions:

Layers Palette in Photoshop
Blending Mode 
Controls how this layer interacts with the layers behind it. Default is Normal.
Layer Opacity 
Controls the total opacity of the layer.
Lock Layer Parts 
Clicking one the options toggles a lock for transparent pixels, image pixels, position, or all. Locked part of layers cannot be edited.
Layer Visibility 
Clicking a layer in this column toggles its visibility. When a layer is invisible, it is not seen on the canvas and cannot be edited. Useful when working on layers below it, or hiding a helper layer (as in the example to the left).
Active Layer 
The blue highlight indicates that this is the layer being edited. Blending Mode, Opacity, Locks, and Fill show and edit the active layer. Many commands need an active layer in order to be executed.
Layer Group 
Layers can be organized into separate groups to make browsing easier.
Layer Tools 
Link Layers allow for you to simultaneously move and transform two or more linked layers. Layer Style (fx) is for adding effects. Masks are for covering and revealing parts of another layer. Adjustment Layers are for changing the qualities of the layer of it's effecting (For example changing the color tones and levels). New Folder allows you to add and new layer group. New Layer creates a new layer. Delete Layer deletes the active layer.


List of Photoshop tools

You'll notice in the image to the right, that most of the tool buttons have a little black arrow to their bottom-right (the move tool and zoom tool are the only ones which are exclusive). This indicates that multiple similar tools can be accessed from that button. To access other tools, click and hold (or right-click) the button to prompt a tool list. You can then select the tool from there.

If you switch to another tool, it becomes the new default for that group; for example: if you switch to the elliptical marquee tool from the rectangular marquee tool (default) and then switch to the move tool, the elliptical marquee tool will remain visible and the rectangular one will be hidden - then, when you click on the marquee tool button, you will select the elliptical variant. Confusing? It shouldn't be, it's so simple that it's silly to try to explain it, just try it out.

You'll also notice that most the tools have a letter associated with it. By pressing this letter on your keyboard, you select the corresponding tool which is in the default position (see above paragraph). To switch to a non-default tool, you can often hold shift and then the shortcut letter to cycle through your options. You should know, however, not all tools can be selected from the keyboard, but all the commonly used ones can be. You can tell the ones you select from the keyboard because they have a letter beside them when you bring up the tool list (see two paragraphs above). So, for example, while you can toggle between rectangular and elliptical marquees with shift + M, you'll need to go to the tool button to select the single row/column marquees associated with that tool.

Toward the bottom you'll see the rotate object and camera rotate tools. These are used when doing 3D works with CS5, and will not be discussed or mentioned again.

All the was to to the bottom is the... I'm not sure what it's called, I just think of it as the color pallet, but that's just one item within it. This is the first place where you control the colors you're working with. Like in MSPaint, you get two colors to play with at a time, a foreground color and a background color. The foreground color is what you actually work with, and the background color is just in reserve.

There's a button to the top right of the lower panel that will switch these colors (like a L-shaped double-sided arrow), or you could just hit X like all the cool kids 8).

The other thing to remember is that black and white are useful colors, and when you find need for them, you can change both colors on your color pallet to them by hitting D, for 'default'.

The last button on the tool bar is the quick mask toggle. This is immensely useful, but I'm not sure this is the place to be talking about it. Remind me to add it to the 'Advanced Selection' section when I'm done with everything else...


There really is one thing you need to learn from this section: Anti-aliasing; what it is, and why it's your friend.

Example of how Anti-aliasing works
Example of anti-aliasing in perspective

This is 12pt font shown at 5 times the normal display size. I've given you a sample of the two most common Windows fonts, Arial and Times, and the font used for the BT logo and such. Just to contrast, if you look to the right that's what these fonts look like at their normal display size.

OK, now that we have some images to reference, lets talk a little bit. Aliasing is what you see in the first row of examples, that's what that type of pixelization is called. What anti-aliasing does is systematically blur the image to maintain information from a higher resolution when its down-sampled. Blurring isn't the right word, really, the right word is anti-alias, and this isn't really a complete explanation, but you get the idea. The reason that photoshop has four types of AA (for short) is because it uses four different algorithms in the down-sampling, the naming scheme is fairly arbitrary.

If you look at the smaller example, 'Sharp' looks 'stronger' than 'Strong' with Times and Joyful Juliana, but 'Strong' looks 'strongest' for Arial. What we can learn from this is that the names are misleading, and that there isn't a 'best' algorithm for all fonts, it all depends on the font and application.

Also, not all fonts are good at lower resolutions when not AA'd. Take a look at Joyful Juliana's aliased. It... looks... horrible... This is what we call a 'bad font' -- well, at least for the purpose of aliased font at lower resolutions. And, seeing as internet browsers don't consistently AA fonts, it would make a terrible web-font (there are other issues too, but I'll spare you them (I can't wait for CSS3)). Remember, not all fonts are created equally - some are good, some are bad, some are ugly, and a few are just evil... That, and, generally speaking, you need to AA your fonts unless you're really going for that retro look.

Thought I'd also mention that all the fonts are using the same color, the aliased fonts may seem darker because they're flat and lack complexity (insert middle-school joke here).


External Links

Photoshop Chalk Talk - A Comprehensive Introduction to Photoshop (Source)

Photoshop on Adobe (Official Photoshop website)