Here is something I want to explain and show, it’s something I apply to many of my pictures, it’s a small thing but can help as a final touch, it can be hard to notice these kind of things in a picture, and if you are starting out it might take years before you ever notice.
I’m sure there are many variations you can do of this since a lot depending on how the picture looks like with the light situation and so on, in these examples a lighter gradient from the top and a darker one from the bottom fits very good, because the environment is layout in a similar pattern.
So you could also experiment having a diagonal gradient coming from the sides, or from the middle with a fade both upwards and down, maybe even just paint with a brush on different spots depending where it’s needed.
I would even say you can use this is an earlier stage of the painting too and doesn’t just have to be a "final touch", that way it gets a bit more in cooperated into the picture and doesn’t look so added on.
But the idea about this effect is, it makes images slightly more real, it’s pretty much impossible to paint a picture with a built in gradient like that and it’s not that effective to do so!
If you check the third image, you can see that image looks way flat, and that’s how it tends to look like when I paint something.
But when I add a gradient I have now modified all the values
even further in the image, making the picture even more complex value wise if you think about it abstractly, almost making sure nothing has the same value in each "pixel".
It also helps with taking away a bit more focus from the edges.
I recommend downloading those two images below so you can compare, you will see the gradient doesn’t even have to be very extreme!
I think this is quite commonly used in movies and photographs as well.
I hope it might come to use,
and thanks for reading!