Computer Graphic 3: Exploring Color Cast with Photoshop Cs5.

Crop Tool

Use the crop tool in Photoshop to crop down an image. Trim away portions of a photo that you may not particularly like and focus on the section of the image that you want to highlight. Select the crop tool from the Tool Bar by pressing C.

Shadow/ Highlight

The Shadow/Highlight adjustment in Photoshop Cs5 is a great feature that offers a quick and easy method of correcting the lighting in your photos. It allows you to correct over- and underexposed areas in your image.

Color Balance

Photoshop allows you to change the levels of colors within an image. In the levels control panel, you'll see a pull-down menu labeled "channel." This allows you to address specific color values. When you select a channel, a histogram much like that in the full RGB channel comes up.
In the RGB mode, we were using the graph to show how much of the image fell into the tonal ranges from pure black to pure white. In this case the "black" and "white points" become colors.

Blur Tool

With the Blur Tool, you can soften portions of an image. This tool can cause areas of an image to appear as if they were out of focus.

Color Replacement

Pull down "Image" > Adjustments > Replace Color.." The masking and adjusting tools apper in one dialog box - a hybrid of "Hue/Saturation" and "Select Color Range" commands.

First of all, we have to select the light blue area. Click with the "eyedropper" (it is already active) somewhere on the box. See on the preview what areas are selected.

Ativate the "Add to sample" eyedropper and click several more times on other hues of light blue so that to select all the blue tissue. If necessary, remove mistakenly selected areas with "Subtract from Sample" eyedropper.

Adjust the color sensitivity of the tool with the "Fuzziness" slider.

You can adjust the color by moving "Hue", "Saturation", and / or "Lightness" sliders until you achieved a desired result.

Dodging and Burning

While there are many ways to adjust the entire picture as a whole, many times you will need to adjust only a portion of a photograph. One part of the photo may be too dark or too light.That's where we will get into a few simple editing tools to adjust only portions of the photo.

A throwback to the days of working in darkrooms, dodging and burning really mean "lightening" and "darkening" portions of the photograph respectively. You can access these tools on the toolbar. One looks like a black lollipop, the other looks like a hand forming a circle.

Sponge Tool

The "Sponge Tool" is used to change the color saturation of an image.
There are two modes of sponge tools: Saturate and Desaturate mode.
Desaturate mode dulls the colors, turning them gray.
Saturate mode increases the color density, making them brighter.
Just select an area of the image to be changed.
Simply select the "Sponge tool" from toolbar.
Set the "Mode" to either "Desaturate" or "Saturate", brush size, and flow in the "options bar".
Click and drag the mouse on the selected area.

Clone Stamp Tool

Photoshop's clone stamp tool allows you to duplicate part of an image. The process involves setting a sampling point in the image which will be used as a reference to create a new cloned area.
Select the Clone Stamp tool

, then check the settings in the options bar. Make sure you have a brush size appropriate for the job. The following settings are fairly typical.
Notes:

Aligned: If this option is selected, the new cloned image will be drawn continuously even if you release the mouse button while drawing. If it is deselected, the clone will begin drawing from the sampling point each time you release the mouse and resume painting.
Use All Layers: If this option is selected, information will be used from all visible layers. Otherwise only the active layer will be used.

Healing Tool

The Healing Brush tool allows you to fix image imperfections such as scratches, blemishes, etc. By sampling the surrounding area or using a predefined pattern you can blend the imperfections into the rest of the image.