How do I draw a color in a pixel with a pen that is solid and does not adjust or blend based on where it is placed but is an absolute color?
Use the Pencil tool in the brush tool section of the tools pallet. Command shift B on the Mac or Control shift B on the PC to cycle through those tools to get to the pencil tool.
That works in some places and doesn't in other places. I'm trying to draw on top of parts that are already drawn on, but not dark enough, so I'm putting an absolute black color on it.
As Bob has said for single pixel, use the pencil tool.
The blend mode of the pencil and layer are set to normal
The opacity of the pencil and layer are set to 100%
The fill of the layer is set to 100%