One of the current cool types of shots are the so called "cinematic photographs." It's not the software filter that makes the photo cinematic or the black bars. Something else does it.
What Is "Cinematic?"
It is not a well-defined technical term. Just as you can't formally describe what "beautiful" is, you can't do that with "cinematic." However, there are certain conditions when we can surely say an image looks "more cinematic." The term is derived from "cinema" and for that we have to look at the films that have been created by those that are professionals in the craft.
The Title of the Article
If you read the title carefully, you will find it's not "How do you make images cinematic?", but "How do you make cinematic images?" There is a vast difference between both approaches. The first one assumes any image can be made cinematic, which is the case scenario for most beginners. They have an image shot with whatever camera they have and then they try to find the secret to make it look "cinematic." The second approach does not have an image at first place. It is a way to create an image that looks cinematic prior pressing the shutter button. The first approach won't always work. I can compare it to "How to make the bread I bought taste good?" You can use spices (filters, presets, or LUTs), but at the end it won't taste right. The reason is you haven't started the way you should.
Is It the Black Bars?
Also called "envelope" in some editors, the "black bars" are the non-lit areas of the screen when projecting a wide-aspect ratio video such as the 2.35:1. As your screen has different proportions, the areas that are not containing the video image will be black. There are movies that are not that "wide-looking", but still look cinematic. Check out "Hugo:"
So, the "black bars" are not the essential thing, although they can be a part of the "cinematic" look.
Is It the Color Grading?
Color grading or applying filters over images or videos is thought to be the bread and butter of the cinematic look. Usually people who need a cinematic look apply an action or a preset over an image and sometimes that doesn't look cinematic at all. Let's see how ungraded footage of a Hollywood movie looks like:
I grabbed a sample "raw" frame from the video. Of course, I'm using just a screenshot, which is not the actual raw file information, but it works for the example. The "raw" looks desaturated and with low contrast. I increased the contrast and the saturation so that it looks "normal." Then I compared it to the final graded version.
As you can see the image with "normal" color correcting (on the left) is supposed to look real. Although it is not blue-tinted as the final version, it still has that "cinematic" look. So, color grading is not the essential thing either, although it helps if the image looks cinematic in camera.
Is It the Lighting?
As we have seen, a "cinematic" image can be that which is seen directly in the camera. One of the components that takes part in making of an image before it goes into the post processing phase is definitely the lighting. Let us see a comparison between two frames from "The Truman Show:"
As you can see the image at the bottom (pun not intended) looks "more cinematic" than the image at the top. So, lighting definitely is a core component of the cinematic look. But does the scene have to be dark to look like from a movie? This screenshot from "Baby Driver" proves it doesn't have to be a dark scene in order to look cinematic.
So, it's not the dark or the light scenes, but the lighting in the scenes. One of the components is the contrast in the shot. I am not talking about the contrast you can increase in post processing. I am talking about the contrast in the scene you are about to photograph or film. This is the ratio between the dark and light parts in the image. Let's take for example two images I snapped with my phone. I increased the contrast of the one on the left quite a lot, while the other is as it was shot.
As you can see, the one on the right looks "more cinematic," even though I haven't increased the contrast like on the first one and it is just an image with a phone camera. The reason is that the second image has the shadows in such a way, so that you see more texture and details of the objects in the scene. This is the so called "non-flat lighting." If you want your images to look "more cinematic," try to stay away from scenes where the light is coming from behind you. That's not a hard rule, but most of the time it will get you closer to the final destination.
Is It the Camera?
The previous second showed you that you can make cinematic images with your phone. It's not the camera, although a camera with a wider dynamic range will give you more details you can play with in post production.
Is It the Resolution?
Certainly not. Resolution has nothing to do with the cinematic look. If you look at paintings of the old masters you will find them "very low resolution," but yet from a distance they look spectacular and "cinematic."
This is an example I deliberately placed the painting as a small thumbnail within the frame to show that it still looks cinematic despite the resolution.
Is That the Secret?
Unfortunately, no. "Cinematic" is a whole experience people have when watching still images or videos that are well-lit and tastefully color graded. Even if you light yours well and color grade them nicely, your results may still lack the "cinematic" feel, because there's something that's taking away from that experience. One of that can be the bad composition of your scene. Another may be the lack of interesting information in the visuals. Cinema is often associated with a telling story. Lack of story or interest in the frame can be an essential part of ruining the "cinematic experience" of the image.
If you want to show cinematic images, try to mimic cinema. There you can see good non-flat lighting, tasteful color grading, composition, and, most importantly, story that is being told. That's by far the most "formal" explanation I can come with for "cinematic." Always remember that you need to start with the right image in camera and everything else is just refining and decoration.