Hue-like Legend spectrum with bright colors for a plot

Question

I use Hue to color ArrayPlot:

Needs["PlotLegends`"]
GraphicsRow[{
 ArrayPlot[gridmatrixpair, Mesh -> False, 
   ColorFunction -> (
    Which[2.0 < #[[1]] < 4.9 && 3*10^8 > #[[2]] > 1*10^6, 
          Hue[(#[[2]] - 1*10^6)*3.344*10^-9],
          True, White
         ] &), 
   ColorFunctionScaling -> False, AspectRatio -> 2/7, 
   FrameLabel -> {y, x}
 ], 
 Graphics[
   Legend[ColorData["Rainbow"][1 - #1] &, 10, "10^6", "10^8", 
    LegendShadow -> None, LegendLabel -> "Power (a.u.)"]]
}]

But as you see the colors in ArrayPlot are brighter than the rainbow colors for the legend. I did not find another ColorData object with brighter colors. What can I do, the scale is changing on and on for different notebooks, so the scale spectrum should be part of the Legend object.

Answer 1

You need to use the same colour distribution in ArrayPlot as you are in Legend (or the other way around):

Needs["PlotLegends`"]
GraphicsRow[{
 ArrayPlot[gridmatrixpair, Mesh -> False, 
   ColorFunction -> (
    Which[2.0 < #[[1]] < 4.9 && 3*10^8 > #[[2]] > 1*10^6, 
          Hue[(#[[2]] - 1*10^6)*3.344*10^-9],
          True, White
         ] &), 
   ColorFunctionScaling -> False, AspectRatio -> 2/7, 
   FrameLabel -> {y, x}
 ], 
 Graphics[
   Legend[ColorData["Hue"][1 - #1] &, 10, "10^6", "10^8", 
    LegendShadow -> None, LegendLabel -> "Power (a.u.)"]]
}]

Alternatively, for v9, use the PlotLegends option which is much superior to the PlotLegends package.