Try these two settings in Acrobat/Reader
Hello I have a stubborn file from one of my clients, the issue is the have a pdf with very thin and light lines. file with thinlines
I have tried printing with PCL driver
printining with Print as image selected in Adobe.
and turning off the the Post Script pass through.
the only change that actually made the lines appear dark enough to see was changing the color profile to B&W
nothing does much the best i can do is make the lines barely visable. they had HP Color LaserJet CP 4525 before and those units printed the line with no issues.
I was trying to get Color By Words to darken the line but every option i tried did nothing.
Today i went to the Online Color By words app
When i went into it and tried to make Dark Whited a little darker it fixed the file.
My issue is that this option is not in any opf the print drivers, anyone know a fix for this file