Getting data driven pages to apply gamma stretch for rasters from current display extent?

Question

I'm trying to export a single, multipage PDF using Data Driven Pages in ArcGIS 10.3. The background images for my maps are 15 large, high res overlapping rasters that are sometimes poor quality due to being underexposed or overexposed, but only in parts of each raster. I've dealt with this problem by going into layer properties, Symbology, and choosing a "Percent Clip" stretch and applying a gamma stretch from the current display extent. That way, my raster colors appear quite good on each page. When I click through the data driven pages manually, the rasters appear nicely rendered, with bright whites and dark blacks for each image.

However, when I export the map using data driven pages using the GUI (I'm a python coding noob), those preferences are not being respected in the final pdf document after exporting via data driven pages.

I thought the solution on the bottom of this page might work, because it forces each page to refresh before printing it to the final pdf, but my scripting knowledge leaves a lot to be desired and I'm having trouble applying the code to my own document.

It sounds like the solution might lie in using python scripting to force data driven pages to draw each page separately (using mxd.dataDrivenPages.refresh() ?), then append all the pages together in a final document.

I've messed around with script I found on these questions,

How to Prevent Data Driven Pages From Hanging on Subsequent Export?
https://support.esri.com/en/technical-article/000014465
https://community.esri.com/thread/19604

but I just can't get it to work.

Has anyone has been able to get the stretched renderer to work in data driven pages?

Answer 1

This is the best I could come up with after some more searching and help from a past colleague.

It seems to apply the gamma stretch to MOST map pages, if not all. So if someone out there has another method I'd still be interested in learning it.

I'm new to python.

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

# Loop through each page in the data driven pages document
for pageNum in range(1, mxd.dataDrivenPages.pageCount + 1):
  mxd.dataDrivenPages.currentPageID = pageNum
  # Refresh the page every time so it re-draws
  arcpy.RefreshActiveView()
  # Export each page to an empty folder
  arcpy.mapping.ExportToPDF(mxd, r" Y:\MultiplePages\Mapbook_" + mxd.dataDrivenPages.pageRow.Record + ".PDF")
del mxd 

import os
# Change working directory
os.chdir("Y:\MultiplePages")
#make sure this lists your pdfs ONLY (they should be in their own folder)
print(os.getcwd())
# List all the pdfs in the folder
pdfList = os.listdir('.')
# Supply a filename for your final document
pdfpath=r"Y:\ClusterMaps_2018.pdf"
# Create the final document
pdfDoc = arcpy.mapping.PDFDocumentCreate(pdfpath)
# Append all the pages in your folder to the final document.
for aPdf in pdfList:
  pdfDoc.appendPages(aPdf)
pdfDoc.saveAndClose()