AddLayer method does not add all bands of .tif image (3 bands total)

Question

I am currently having trouble getting 3-band raster's to display correctly when I call the arcpy.mapping.AddLayer() method. It should be said that I am using a pre-existing mxd template to automate the mapping process and output jpg's as the final product.

here is a snippet to demonstrate how I am adding the layers;

    import arcpy

    mxd = arcpy.mapping.MapDocument("path_to_mxd")

    data_frames = arcpy.mapping.ListDataFrames(mxd)

    df = data_frames[0]

    layer = arcpy.mapping.Layer("path_to_layer")

    arcpy.mapping.AddLayer(df, layer, "TOP")

this code adds the layer object but it does not include all bands of the image so what I am left with looks like a negative copy of the original image. I have tried to work around this by including a layer with correct symbology and then using the ApplySymbologyFromLayer_management() method but it does not work and when tried with the python command line in ArcMap, the image(s) display a lock in the bottom right corner of their description in the table of contents. I only want the images to display with RGB composite symbology. Any help would be greatly appreciated and I will check often if more info is needed. Also I did read the post titled: "Is there a way to programatically force RGB (3 bands)" etc... the rasters I am adding already contain 3 bands and arcpy is only adding one in a stretched format so please consider this when answering, Thanks

Answer 1

If you can get your raster layer displayed as you want in ArcMap, then I would recommend saving that layer as a layerfile, and then using the layerfile name (with its full path) in place of "path_to_layer" when you create the layer object.