GS-PS: Photoshop: GS-PS: Type, Quick Masks, and Levels

Review

Adding Type

To add type to images use the Type tool ("T" in the Toolbox).
To enter a single line of text, click on the image with the type tool. Then type. A type layer is automatically created.
To create a paragraph (column) of text, click and drag with the type tool, then start typing. When you enter the text, it will wrap at the point where you stopped dragging.
To reposition the text while you are using the Type tool, press the Ctrl key.The Type will change into the move tool so you can move the text box.
When you are finished typing, click the check mark in the options bar. To cancel, click the X mark in the options bar.
To adjust the color and format of your type, select the type and then change the settings in the options bar (at the top of the Photoshop desktop), or use the Character or Paragraph palettes (to display these palettes, click on the text palettes button ( ), which appears in the Options bar whenever the Type tool is selected).
When you use the Type tool, a type layer is automatically created. As long as your type is on a Type layer it is editable. If you convert it to an image layer by rasterizing it (Layer>Rasterize), you will no longer be able to edit it.

Quick Mask Mode

A mask lets you select an area of your document that is (or isn't) affected when you make color changes, use patterns, adjust colors or set gradients.
If you want to colorize a part of an image, isolate an area using any of the selection tools

Then, switch to Quick Mask mode. Photoshop fills everything but your selection with a 50% red screen to indicate that it is protected.

Using the Brush tool, anywhere you paint with white is added to your selection. Anything you paint with black is removed from your selection and covered with the 50 percent red screen.

When you switch back the Standard Editing Mode, your selection, plus any additions you made in Quick Mask mode, are still selected.

Levels

The Levels command is an excellent tool for adjusting contrast.
Create an Adjustment Layer, and choose Levels
The Levels dialog box displays a histogram of the brightness values of the pixels in your image. There are two sets of sliders (triangles): input levels and output levels. For most editing tasks, use the input levels sliders (the three triangles just below the histogram).
To increase contrast (create more dark and light pixels): Move the left and right sliders toward the middle.
To adjust the midtones: Move the middle input levels slider to the left to lighten midtones, and move the middle slider to the right to darken the midtones.
Keep the Preview box checked in order to see the effects of moving the sliders on your image.
To agree to the adjustment, click OK.
To cancel it, click Cancel.

In the above example, there are few (if any) pixels that are white or even light gray. By moving the right slider towards the middle, we can lighten image to correct the exposure. Because the Preview box in the layers palette is checked, we can see the result on our image as we adjust the sliders.

In the above example, the Levels dialog box Channel popup menu is set to the default of RGB, which means the histogram represents a combination of all of the channels (Red, Green, and Blue light) in the image. You can use Levels on an individual channel, but this distorts the color balance of the image, so in most cases should be avoided
The Levels command is often a good way to get a more even distribution of brightness of pixels. But this is not always desirable. For example, a properly exposed photograph of something dark such as a coal mine would be dark, and an image of a snow scene would be white. In such cases the histogram would be lopsided. In such a case there may be no need to make an adjustment in the Levels dialog box.

GS-PS: Photoshop