To get this look of dark background that outlines your subject from the foreground is just simple and easy. I dont use Photoshop neither do i manipulate my photos other than normal editing so lets ride. To get this look, there are things involved; good lighting, good shallow DoF on the out of focus areas, good editing skill and of course a good smartphone camera or DSLR.
Good lighting: This is the major source of getting this photo done because you can’t create a shadow or a dark background if you don’t properly illuminate the subject, it is the light that is flashed on the subject that gives the dark background and get the subject standing out.. So this is how i get about my own lighting. First i use an artificial lighting source, i don’t use a natural lighting source because the whole photo will be illuminated leaving everything bright and clear. Using an artificial light source like a florescent light or a flash is what works. So i place the light at an angle i know it will only illuminate my subject and over look the background. I then in my phone flash ( it has to be continuously on, this is a feature in my smartphone as a camera mechanism). I will point the camera to my subject as close as i can to make my macro. After making this photo you will see how the background came out all shady and dark😄😁✌🏾.
Shallow DoF/focus : This is also important because what you keep in focus while making the shot is what matters and how the DoF came out. The out of focus area will also look somehow dark and not well illuminated because it is already in the bokeh. The greater bokeh and shallow DoF the more outlined the subject becomes from the background, making your photos look more professional. ☺️
Good editing skills: This is like the vital part of the process of making this photograph. You have already created your photographs and have gotten the dark backgrounds. Now there is something left, to edit the photo and make it more enhanced and epic because in the world of photography, i believe no photo is left untouched😃 because we have to get the best out of them. So right now the editing thats to be done in the photo to get the final outcome is; the light, you have to check the light intensity of the photo to know if it is to illuminated or the other way round, so you will just adjust the light to what you want. Now the contrast, this is like a secret. You have to increase the contrast to get a deep dark shade in the backgrounds.