The color of a particular cell in a multiband RGB grid stack is determined by the combination of values of that cell in the component layers. You can generate a single band pseudo-color image with a colormap file by combining the component grids so there is a different value for each unique combination of red, green and blue values. The number of combinations must be less than 256.
Grid: comb1 = COMBINE (red, green, blue)
Tables: SELECT comb1.vat
Tables: UNLOAD cmap.clr value red green blue COLUMNAR format.txt
Tables: &SYS DEL format.txt
Arc: GRIDIMAGE comb1 cmap.clr img_pseudo.tif tiff
The .clr file serves as a standard colormap file.
This procedure can be used with RGB images by first converting them to a gridstacks with the IMAGEGRID command.
Get help from ArcGIS experts
Download the Esri Support App