Yes you can self teach but how many years are you going to waste doing mediocre stuff before someone points out a basic mistake.
errr... I spent close to a good 2 years printing for myself and others who were willing to experiment with me,
to eventually feel convinced that I am color-correcting and making prints of the best quality here.
Interestingly, I dont know whether some of us have heard of this, but, about a decade or two back in the US,
a group of photographers got together and started this thing where in they would make their prints,
and send them to another photographer. From photographer A to photographer B.
The photographer B would have a look at the prints, and give his feedback to the photographer A,
then add his prints and send them all, to photographer C.
By the end of it, if the prints ever came back to the person who started this,
the photographer A would end up with a heavy bunch of pictures to give his feedback on.
I was told, it didnt go too long, as photographers 6 or 7th down the line,
were finding it a tad bit expensive to courier the accumulated prints of the 5 or 6 before them.
Sorry.. took off in another direction. But, maybe its time to do that.
And instead of 12x18, like the photographers mentioned above, we can start with A4s.