Graphics > Graphics Gallery > Modifying Visualizations > Loading Default Color Tables

## Loading Default Color Tables

IDL uses color tables to associate pixel values in indexed images with specific RGB color values.

To define a color table in graphics functions such as IMAGE and MAP, use the RGB_TABLE property. If no color table is defined, these graphics display in gray scale. The color tables on the right are ColorBrewer schemes.

IDL provides predefined color tables, each with an index value as shown in the following table. At any time during your IDL session, you can pull up a widget window showing a brief listing of the predefined colortables by typing the following command at the IDL prompt:

XLOADCT

| Name | Sample |  |  | Name | Sample
--- | --- | --- | --- | --- | --- | ---
0 | Black-White Linear |  |  | 41 | CB-Accent |
1 | Blue-White Linear |  |  | 42 | CB-Dark2 |
2 | Green-Red-Blue-White |  |  | 43 | CB-Paired |
3 | Red Temperature |  |  | 44 | CB-Pastel1 |
4 | Blue-Green-Red-Yellow |  |  | 45 | CB-Pastel2 |
5 | Standard Gamma-II |  |  | 46 | CB-Set1 |
6 | Prism |  |  | 47 | CB-Set2 |
7 | Red-Purple |  |  | 48 | CB-Set3 |
8 | Green-White Linear |  |  | 49 | CB-Blues |
9 | Green-White Exponential |  |  | 50 | CB-BuGn |
10 | Green-Pink |  |  | 51 | CB-BuPu |
11 | Blue-Red |  |  | 52 | CB-GnBu |
12 | 16 Level |  |  | 53 | CB-Greens |
13 | Rainbow |  |  | 54 | CB-Greys |
14 | Steps |  |  | 55 | CB-Oranges |
15 | Stern Special |  |  | 56 | CB-OrRd |
16 | Haze |  |  | 57 | CB-PuBu |
17 | Blue-Pastel-Red |  |  | 58 | CB-PuBuGn |
18 | Pastels |  |  | 59 | CB-PuRd |
19 | Hue Sat Lightness 1 |  |  | 60 | CB-Purples |
20 | Hue Sat Lightness 2 |  |  | 61 | CB-RdPu |
21 | Hue Sat Value 1 |  |  | 62 | CB-Reds |
22 | Hue Sat Value 2 |  |  | 63 | CB-YIGn |
23 | Purple-Red + Stripes |  |  | 64 | CB-YIGnBu |
24 | Beach |  |  | 65 | CB-YIOrBr |
25 | Mac Style |  |  | 66 | CB-BrBG |
26 | Eos A |  |  | 67 | CB-PiYG |
27 | Eos B |  |  | 68 | CB-PRGn |
28 | Hardcandy |  |  | 69 | CB-PuOr |
29 | Nature |  |  | 70 | CB-RdBu |
30 | Ocean |  |  | 71 | CB-RdGy |
31 | Peppermint |  |  | 72 | CB-RdYiBu |
32 | Plasma |  |  | 73 | CB-RdYiGn |
33 | Blue-Red 2 |  |  | 74 | CB-Spectral |
34 | Rainbow 2 |  |  |  |  |
35 | Blue Waves |  |  |  |  |
36 | Volcano |  |  |  |  |
37 | Waves |  |  |  |  |
38 | Rainbow 18 |  |  |  |  |
39 | Rainbow + White |  |  |  |  |
40 | Rainbow + Black |  |  |  |  |

Also see Color Tables in Direct Graphics.