Hillshading

[shrimpie1911]

I'm currently trying to make "hill shading" for my server. I've have download the tiff file from USGS (the tiff file is very dark i don't know if it's ok or not). I've following this tutorial: https://wiki.openstreetmap.org/wiki/Mapnik/Hillshading_using_Mapnik,_GDAL_and_SRMT_data
Everything compile and run fine, but when i go to my web page nothing change, i've try to delete and rerenderd all tiles, the map is still the same. Can someone help please?

Thank you in advance for the help and sorry for my bad english.