Color

All marks have a default color that is used when there are no fields on color. Most marks use a blue color while text marks are shown in black.
The Color property encodes data by assigning different colors to the marks in a data view based on the values of a field. The effect of color-encoding your data view depends on whether you use categorical or quantitative colors. You can also use the drop-down control to specify other color properties such as transparency, borders, and halos.

Color encodings are shared across multiple worksheets that use the same data source to help you create consistent displays of your data. For example, if you define the Western region to be green, it will automatically be green in all other views in the workbook. To set the default color encodings for a field, right-click the field in the Data window and select Default Properties >Color.

Categorical Colors

When you add a dimension to the Color target on the Marks card, a categorical legend is added based on the members of the field. To modify the colors used in the legend, right-click on the legend and select Edit Colors or double-click on the legend. The Edit Colors dialog box for a categorical legend is shown below.

To change the color of a member:

1. Select the member on the left and then select the new color in the palette on the right.
   
2. When finished, click OK to close the Edit Colors dialog box.
   

You can select a different color palette from the drop-down menu in the upper right of the Edit Colors dialog box. Select from either categorical palettes or ordinal palettes. A categorical palette, such as Tableau 20, contains several distinct colors that can be assigned to dimension members that have no inherent order. Ordinal palettes contain a spectrum of related colors, which can be used for dimension members that have an associated order such as dates and numbers.
Once you select a palette, click Assign Palette to automatically assign the new palette colors to the members in the field. When finished, click OK to view the changes and close the dialog box.
To return to the automatic color settings, click Reset in the Edit Colors dialog box.

Quantitative Colors

When you add a measure to the Color target on the Marks card, a quantitative legend is added creating a continuous range of colors. You can modify the colors used in the range, the distribution of color, and other range attributes in the Edit Colors dialog box. Right-click the legend and select Edit Colors or double-click on the legend. The Edit Colors dialog box for a quantitative legend is shown below.

To change the color used in the range, click on the color indicator to the right of the range and select a new color in the spectrum. You can select a new palette from the Palette drop-down menu. You can choose between a sequential palette and a diverging palette. A sequential palette shows a simple range of values using color intensity to indicate one end of the range from the other. A diverging palette shows two ranges of values using color intensity to show the magnitude of the number and the actual color to show which range the number is from. Diverging palettes are most commonly used to show the difference between positive and negative numbers.
Each of the options for formatting quantitative colors are described below:

Using Stepped Color

You can modify how the colors are distributed by selecting Stepped Color. The stepped color option groups the values into uniform bins each given a unique color. Use the text box to specify how many bins you want to use. For example, if you had a range of values from 0 to 100 and you select 5 steps, the color range would be broken up every 20 units. That means that all points between 0 and 20 would be colored the same, all points between 21 and 40 would be colored the same and so on. The dialog box below shows the color range broken up into five steps.

If a diverging color palette is selected, the center point is shown on the color ramp with a small black mark. When the number of steps is odd, the center mark is placed in the middle of the center step. When the number of steps is even, the center mark is placed at the boundary of the center-most two steps.

Reversing the Color Palette

Select Reversed to switch the order of colors in the range. For example, if you want lower values to have a darker intensity in a sequential palette, reverse the palette. Alternatively, if you are using a diverging color palette with red representing -100 to 0 and blue representing 0 to 100, you can switch the colors using the reverse option to make blue represent the negative range and red represent the positive range.

Using the Full Color Range

When you are using a diverging color palette you can select to Use Full Color Range. When you select this option, Tableau assigns the starting number a full intensity and the ending number a full intensity. If the range is from -10 to 100, the color representing negative numbers changes in shade much more quickly than the color representing positive numbers. If you do not select Use Full Color Range, Tableau assigns the color intensity as if the range was from -100 to 100 so that the change in shade is the same on both sides of zero. The image below shows a Red-Blue diverging color palette for values from -231 to 55,000. Without using the full color range, -231 (the value for Green Tea) shows as gray. When the full color range is used, -231 is represented by a full red.

Limiting the Color Range

You can limit the range that the colors are distributed across using the advanced options. When you click Advanced in the Edit Colors dialog box, you can choose to specify the start, end, and center values on the range by selecting the check box and typing a new value into the text box. The Start value is the lower limit in the range, the End value is the upper limit, and the Center value is where the neutral color is located on a diverging color palette.

Resetting the Color Range

To return to automatic color settings, click Reset in the Edit Colors dialog box.

Transparency

You can modify the transparency of the marks using the drop-down control for Color on the Marks card. Changing the transparency is especially useful in dense scatter plots or when you are looking at data overlaying a map or background image. As you slide the slider toward the left the marks become more transparent.

Effects

Click Color on the Marks card to open a drop-down control where you can modify other color properties. You can set up Mark Borders, Mark Halos, and Markers.

Mark Borders

By default, Tableau displays all marks without a border. You can turn on the mark borders for all mark types except text, line, and shape. On the Color drop-down control, select a mark border color.

Borders are often useful for distinguishing between closely spaced marks. For example, the view shown below has mark borders turned on (left) and turned off (right). As you can see, when borders are turned on, marks become more easy to distinguish in the areas where they are tightly clustered.

You can also use transparency to show the density of marks.

Leaving mark borders off is particularly useful when you are viewing a large number of small marks that are color-encoded. It can be difficult to see the color encoding because the borders dominate the marks.
For example, the view shown below displays bars that are segmented by a large number of color-encoded dimension members. When mark borders are turned on. some marks are difficult to identify by color. When borders are turned off, the marks can easily be distinguished.

Mark Halos

In order to make the marks in a view more visible against a background image or map, you can surround each mark with a solid contrasting color called a halo. Mark halos are available when you have a background image or a background map. On the Color drop-down control, select a mark halo color.

Markers

When you are using the Line mark type, you can add a marker effect to show and hide the points along the line. You can show selected points, all points, or no points. On the Color drop-down control, select one of the Marker effects.