Implicating monochrome_background → simple_background
Link to implication

Reason:

As per wiki's own definition

I'd say that the wiki is outdated.
After undetailed_background got aliased to it, simple_background has been mostly used as an umbrella tag for, well, simple backgrounds: anything that's between plain_background and detailed_background.

Based on the old forum discussions, this is how they're supposed to be used:
plain_background:
post #364396 post #244931 post #334348

simple_background:
post #100328 post #49665 post #137361

detailed_background:
post #171991 post #222870 post #416529

But as you can see from the searches, that tag group is bit of a mess. I'm not sure if it's worthwhile to try to keep plain_background and simple_background separate, when they get mixed up all the time. Maybe we should just alias them?

hmmm, I think this will be my next project as it was probably me who started this in the first place

Simple_background was meant for undetailed backgrounds with not much in them, like a grassy field, and plain_background is meant for a background that is just color or a simple pattern and is not meant to place the character in any sort of setting

Rainbow_Dash said:
Simple_background was meant for undetailed backgrounds with not much in them, like a grassy field, and plain_background is meant for a background that is just color or a simple pattern and is not meant to place the character in any sort of setting

Hm, so my third simple_background example...
post #137361
...should actually be tagged as plain_background?

In any case, would be good if those wiki entries got updated. I'd do it myself, but I'm not entirely sure what should go where. :|