Dialog box - Pseudo Color

Use the Image > Pseudo Color... command, to change the active image's color table, or to define a new color table. You can use pseudo color tables to have gray-value images displayed in color. Then every intensity value in an image will be allotted a hue.

Prerequisite: This command is only available when the active document is a gray-value image.

Click on one of the areas in the dialog box shown schematically below, to jump to the corresponding help topic.

(1) Toolbar in the dialog box

	Load Color Table	Click this button to load a formerly saved color table.
	Save Color Table	Click this button to save the current color table. You can always use saved color tables to color other gray-value images.
	Manage Color Table	Click this button to edit, delete, or duplicate saved parameter sets.
	Remove Color Table	Click this button to delete the current color table. The image in the image window will be displayed as a gray-value image again.
	Undo Last Operation	Click this button to undo the last operation that was done in the Pseudo Color dialog box. Here you can undo almost any number of operations step by step. Most of the operations can be undone as long as you keep this dialog box open.
	Redo Last Operation	Click this button, to undo the results of the last undo command.

(2) Displaying the current color table

In the dialog box, the current color table will be shown. In the illustration, for example, you can see the predefined color table Rainbow-BlackToRed.

The color table shows you in which color the image's individual intensity values will be displayed. On the left, the intensity value 0 (black) is shown, on the right, the intensity value 255 (white).

(3) Editing a color table

In the Edit Color Table group, you can assign colors to a range of intensity values. You define the intensity range via the Start and End fields. In the Start field, enter the first, and in the End field the last, value of the intensity range.

Alternatively, you can define the start and end values for the intensity range directly in the displayed color table. To do this, keep the left mouse button pressed and drag the mouse over the intensity range you want. The values in the Start and End fields are updated correspondingly.

To choose the colors, click on the color fields next to the Start and End fields. By doing this you will open the Colors dialog box. In it, select the color you want and confirm it with OK. The color you've chosen will then be shown in the Pseudo Color dialog box.

Click the Apply button to apply the settings in the Edit Color Table group to the current color table.

To assign the intensity range one single color, select the same color in both color fields.

To assign the intensity range a color gradient, select a different color in each of the color fields. Enter in the middle field Divisions the number of colors that the color gradient is to contain. In this way you can display the intensity values of an image in e.g., only 10 colors.

The illustration shows color tables in which a color gradient from yellow to green has been set. The tables differ in the value that has been entered in the Divisions field. The value used is specified on the right.