IGOR Pro 6 Color Tables

Igor 6 has 58 built-in color tables for use with false color images and with graph traces. (Igor 5 has 44 color tables and Igor 4 has only 10.)


Color Table Visual Guide

New Igor 6 color tables

Igor 5-compatible 256-color tables

Igor 5-compatible Gradient color tables

Igor 5-compatible Special-purpose color tables

Igor 4-compatible color tables

Number of Colors

The number of color entries for each color table varies (Igor 6 color tables are shown in red):

Color Table Name Colors Notes
RainbowCycle 360 Red, green, blue vary sinusoidally, each 120 degrees (120 values) out of phase. The first and last colors are identical.
Rainbow4Cycles 360 4 cycles with one quarter of the angular resolution.
BlueGreenOrange 300 Three-color gradient.
BrownViolet 300 Two-color gradient.
ColdWarm 300 Multicolor gradient for temperature.
Mocha 300 Two-color gradient.
VioletOrangeYellow 300 Multicolor gradient for temperature.
SeaLandAndFire 256 Topographic color table. Sea level is at 25%.
GreenMagenta16 16 Similar to the 14-color National Weather Service Motion color tables (base velocity or storm relative values), but friendly to red-green colorblind people.
EOSOrangeBlue11 11 Colors for diverging data (friendly to red-green colorblind people).
EOSSpectral11 11 Modified spectral colors (friendly to red-green colorblind people).
dBZ14 14 National Weather Service Reflectivity (radar) colors for Clear Air (-28 to +24 dBZ) or Precipitation (5 to 70 dBZ) mode.
dBZ21 21 National Weather Service Reflectivity (radar) colors for combined Clear Air and Precipitation mode (-30 to 70 dBZ).
Web216 216 The 216 "web-safe" colors, provides a wide selection of standard colors in a single color table. Intended for trace f(z) coloring using the ModifyGraph zColor(traceName )=... feature.
Grays256 256
Rainbow256 256
YellowHot256 256
BlueHot256 256
BlueRedGreen256 256
RedWhiteBlue256 256
PlanetEarth256 256
Terrain256 256
Red 256 Black -> red -> white.
Green 256 Black -> green -> white.
Blue 256 Black -> blue -> white.
Cyan 256 Black -> cyan -> white.
Magenta 256 Black -> magenta -> white.
Yellow 256 Black -> yellow -> white.
Copper 256 Black -> copper -> white.
Gold 256 Black -> gold -> white.
CyanMagenta 256
RedWhiteGreen 256
BlueBlackRed 256
Geo 256 Popular geographic color table with water and land colors, sea level is around 50%.
Geo32 32 Quantized to classify altitudes. Sea level is around 50%.
LandAndSea 255 Rapid color changes above sea level, which is at exactly 50%. Ocean depths are blue-gray.
LandAndSea8 8 Quantized, sea level is at about 22%.
Relief 255 Slower color changes above sea level, which is at exactly 50%. Ocean depths are black.
Relief19 19 Quantized, sea level is at about 47.5%.
PastelsMap 301 Desaturated rainbow-like colors, with sharp green->yellow color change at sea level, which is at approximately 2/3 (66.67%). Ocean depths are faded purple.
PastelsMap20 20 Quantized. Sea level is at about 66.67%.
Bathymetry9 9 Colors for ocean depths. Sea level is at 100%.
BlackBody 181 Red -> Yellow -> Blue colors that are calibrated to black body radiation colors (neglecting intensity) when the color table rang is set from 1,000 ºK to 10,000 ºK. Each color table entry represents 50 ºK.
Spectrum 201 Rainbow-like colors that are calibrated to the visible spectrum when the color table range is set from 380 to 780 nm (wavelength). Each color table entry represents 2nm. The colors do not completely fade to black at the ends of the color table.
SpectrumBlack 476 Rainbow-like colors that are calibrated to the visible spectrum when the color table range is set from 355 to 830 nm (wavelength). Each color table entry represents 1nm. The colors fade to black at the ends of the color table.
Cycles 201 Ten grayscale cycles from 0 to 100% to 0%.
Fiddle 254 Some randomized colors for "fiddling" with an image to detect faint details in the image.
Pastels 256 Desaturated Rainbow.
Grays 100 Igor 4-compatible.
Rainbow 100 Igor 4-compatible.
YellowHot 100 Igor 4-compatible.
BlueHot 100 Igor 4-compatible.
BlueRedGreen 100 Igor 4-compatible.
RedWhiteBlue 100 Igor 4-compatible.
PlanetEarth 100 Igor 4-compatible.
Terrain 100 Igor 4-compatible.
Grays16 16 Fewer colors to quantize an image into bands. Igor 4-compatible, though not returned by Igor 4's CTabList function.
Rainbow16 16 Igor 4-compatible, though not returned by Igor 4's CTabList.

Color Table Ranges

The range of data values that maps into the range of colors in the table can be set either manually or automatically using the Modify Image Appearance dialog.

When you choose to autoscale the first or last color, Igor examines the data in your image and uses, respectively, the minimum or maximum data values found.

By changing the "First Color at Z=" and "Last Color at Z=" values you can examine details in your data.

For example, when using the Grays color table, you can lighten the image by assigning the First Color (which is black) to a number lower than the image minimum value. This maps a lighter color to the minimum image value. To darken the maximum image values, assign the Last Color to a number higher than the image maximum value, mapping a darker color to the maximum image value.

Data values greater than the range maximum are given the last color in the color table, or they can all be assigned to a single color or made transparent. Similarly, data values less than the range minimum are given the first color in the color table, or they can all be assigned to a single color (possibly different from the max color), or made transparent.

Some of the color tables are designed for specific uses and specific numeric ranges.

The BlackBody color table is designed to show the color of a heated "black body" (though not the brightness of that body) over the temperature range of 1,000 to 10,000 degrees Kelvin.

The Spectrum color table is designed to show the color corresponding to the wavelength of visible light as measured in nanometers over the range of 380 to 780 nm.

The SpectrumBlack color table does the same thing, but over the range of 355 to 830 nm. The fading to black is an attempt to indicate that the human eye loses the ability to perceive colors at the range extremities.

The dBZ14 and dBZ21 color table are designed for displaying weather maps using standard National Weather Service radar colors and values.

The LandAndSea, SeaLandAndFire, Relief, and PastelsMap color tables all have a sharp color transition which is intended to denote sea level.

The LandAndSea and Relief tables have this transition at 50% of the range. You can put this transition at a value of 0 by setting the minimum value to the negative of the maximum value:

ModifyImage imageName, ctab={-1000,1000,LandAndSea,0}	// image plot
ColorScale/C/N=scale0  ctab={-1000,1000,LandAndSea,0}	// colorscale

The PastelsMap table has this transition at 2/3 of the range. You can put this transition at a value of 0 by setting the minimum value to twice the negative of the maximum value:

ModifyImage imageName, ctab={-2000,1000,PastelsMap,0}	// image plot
ColorScale/C/N=scale0  ctab={-2000,1000,PastelsMap,0}	// colorscale

This principle can be extended to the other color tables to position a specific color to a desired value. Some trial-and-error is to be expected.

Note: The BlackBody, Spectrum, and SpectrumBlack color tables are based on algorithms from the Color Science web site.

Reference: Wyszecki, Gunter, and W. S. Stiles, Color Science : Concepts and Methods, Quantitative Data and Formula, 628 pp., John Wiley & Sons, 1982.