I am a very basic user, I scan pencil (comic) drawings as tiffs and use Photoshop cc 2015 to darken the lines and clean up a bit, and put text balloons and save again as tiffs. I use the 'levels' layer to blacken.
I have done this for a while (15-20 drawings) but now I have a page that shows nicely on screen but when I save as tiff (or bmp or anything) the black drawing lines that I see on screen are grey.
When I merge they also become grey. When I merge and add a new 'levels' layer it shows black nicely again but when I merge and/or save, they black becomes grey again. I suspect I changed a setting.
Before merging it looks like this:
After merging or saving it looks like this: