ColorFunction help?

*To*: mathgroup at smc.vnet.net*Subject*: [mg74888] ColorFunction help?*From*: AES <siegman at stanford.edu>*Date*: Tue, 10 Apr 2007 05:15:22 -0400 (EDT)*Organization*: Stanford University

Some time back I asked about creating what a respondent later called "White to Color" color functions for contour and density plots, and after some further experimentation I've found that if I define k1=xx; k2=yy; k3=zz; myPlotColor[i_] = RBGColor[1 - k1 i, 1 - k2 i, 1 - k3 i] with k1, k2, k3 each set equal to either 0 or 1, and then use ColorFunction->myPlotColor in the plot command, I get just the results I want. For example if I execute the seven lines (either in a single cell or as separate cells) k1 = 0; k2 = 1; k3 = 1; red[i_] = RGBColor[1 - k1 i, 1 - k2 i, 1 - k3 i]; gCP = ContourPlot[(x + y)/2, {x, 0, 1}, {y, 0, 1}, ColorFunction -> red]; k1 = 1; k2 = 0; k3 = 1; green[i_] = RGBColor[1 - k1 i, 1 - k2 i, 1 - k3 i]; gDP = DensityPlot[(x + y)/2, {x, 0, 1}, {y, 0, 1}, ColorFunction -> green]; Show[GraphicsArray[{{gCP, gDP}}]]; I get the beautiful red ContourPlot gCP that I want from lines 1 thru 3; the beautiful green DensityPlot gDP that I want from lines 4 thru 6; and then the two of them together from line 7. What puzzles me, however, is that if I replace the string "green" by "red" in lines 5 and 6 above, the individual plots CP and DP from lines 1 thbru 6 still come out red and green as before --- but the two graphics produced by the Show[ ] command in line 7 now both come out green. The DP resulting from line 6 obviously knew it was supposed to be green when it was first rendered, even though its ColorFunction was confusingly named "red", because red[i_] had been redefined using k values appropriate to green in line 5. How come it forgets all about this when Show time comes around? [Email cc of replies welcomed] come out green**.