THE (DIGITAL) IMAGE
Rather than mythically setting up humans’ relationship to the image, which I would most certainly do an underwhelming job of, let’s start with the assumption that you generally know what an image is.
Take a moment to ask yourself, though: What makes an image an image? What defines it as such? What traits make up any given image?
Let’s take the risk of consulting an actual definition of the word. The most appropriate definition given by Merriam-Webster reads:
A visual representation of something: such as
1. a likeness of an object produced on a photographic material
2. a picture produced on an electronic display (such as a television or computer screen)
This narrows the overall idea down, almost too much, but certainly fits within the context of how we are approaching the term.
So, in keeping the above in mind:
WHAT TRAITS AND PROPERTIES DEFINE AN IMAGE?
The focal point of an image. Not all images have subjects, but those that do, the subject should (usually) be readily identifiable. Composition, focal point, color, and contrast should all assist in drawing the viewer’s eye to your subject.
Once there, much of the tone of the image will be decided by your subject’s action (or inaction), position, and expression, if applicable.
SETTING (BACKGROUND AND FOREGROUND)
Is it expected, given your subject? For instance, if your subject is a businessman, it would be expected for him to be in an office setting. But what if he were in a jungle? Or the middle of an endless desert?
What might be in the background or foreground that affects the overall idea of the image?
How is your subject positioned in the frame? Also, how are they positioned relative to the background and any other subject(s)?
Is your subject center-framed, or positioned near one of the
Where is the camera placed on the x- and z-axes?
How high is the camera, along the y-axis?
What sort of field-of-view are we seeing the image through?
Is the camera pointing straight out? Up? Down?
Where is the focus point? If it’s not on the assumed subject, then the image would be considered to be out of focus.
How deep is our depth-of-field?
SHAPE AND ORIENTATION OF FRAME
Is your image a rectangle? Square? Circle? Perhaps it’s in the shape of a spoon?
Is your image situated in a landscape orientation, or portrait orientation? How might certain orientations be more suited for some viewing devices than others?
What is the aspect ratio of your image, and how does this affect how the viewer perceives the subject and composition?
Depending on the format, there are a few different considerations here.
In a physical, analog piece: How large is it, physically? Does it fit in your hands, or does it take up an entire wall? The same fundamental image, displayed in these two different contexts, makes for very different viewing experiences.
In a digital image, what is the resolution of the image? Past a certain point, excessive resolution makes no difference to the viewing experience of most things, but it all depends on the setup. Viewed on a smart phone at normal distance, there’s no substantial difference viewing anything over 1080p. But if you are close to a screen that is 100 feet wide, then you’ll notice much higher increases in resolution.
How much detail is there? This question relates to both physical and digital media. Fine detail, if meant to be experienced as part of the total image, is something that is more suited for larger physical sizes, and higher resolutions. If the physical medium is small and/or if the display isn’t of sufficient resolution, then detail won’t be a substantial part in the experience of the image. This leads to interesting quandaries in an age where most people consume images on their portrait-oriented smartphones.
Is the image bright, neutral, or dark? This naturally has a significant impact in how the viewer will interpret the subject and meaning of the image.
Contrast has become a type of trope when it comes to motion pictures and photography.
High contrast, with its bright highlights and/or deep shadows, is seen as dramatic and/or action-oriented. The shadows are also especially suited to the horror genre.
Low contrast is more commonplace in comedy, romance, or independent features. Most of these genres tend to be more based in reality, and the contrast levels are arguably more lifelike.
Are there colors that stand out in the image? How might they impact the way that the viewer forms thoughts and feelings about the image? There is a lot of cultural association to a lot of colors, but especially the primary (red, blue, and yellow) and secondary colors (green, purple, and orange).
Is the overall image warm or cool? A warm image, featuring reds, oranges, yellows, or violet; might seem inviting or positive. A cold image, featuring primarily blues, can be alienating or depressing. Where does this association come from? Perhaps from the seasons? Can you think of a scene where the typical associations of warm and cold might be flipped?
Is there a tint of another color? Why was that color chosen? What might that color mean?
What level of saturation are the colors? Is there selective saturation? What might it mean to leave some colors and not others?
Is there a unique color grade? What does this grade say about the piece? Does it relate to anything else via association? Does it reinforce or subvert tropes and expectations?
How else is color used in the frame? What color are clothes? Items? Walls? Floors?
what are the elements of a digital image?
So far, we’ve listed some of the properties that might be used to describe any given image, from a painting to a motion picture and anything in between. But what is an image really made up of? It’s easy enough to answer this question for most physical mediums. Canvas. Oils. Graphite. Etc. But most images that we see are digital, so what then?
The smallest measurable element of a digital image is the pixel.
Pixels are somewhat abstract in that they are essentially shapes of color. Theoretically, a pixel could be any shape, but realistically it wouldn’t make much sense for a pixel to be anything radically different than a quadrilateral. And that is why, practically, pixels have always been four-sided shapes; rectangles and squares. The pixels themselves line up in perfect rows, and stack perfectly on top of each other, leaving no (theoretical) space between them. But like all things digital, they are really just made of ones and zeroes.
Fundamentally, a pixel is defined by two simple things: color and pixel aspect ratio.
Digital color, to this point, has long been defined in a number of somewhat redundant methods; the most common of which are arguably HSL and RGB.
HSL stands for Hue, Saturation, and Lightness. Hue defines what color the pixels are. Saturation defines how much of that color there is. Lightness defines that color’s proximity to black or white.
RGB stands for Red, Green, and Blue. Red, green, and blue are the additive colors. That means that these three colors, in the form of light and in equal measure, will create white or grey. Shifting the balance of these three colors, you are able to make any other color.
Similar to the concept of ISO and Gain, HSL and RGB are simply two different ways of conveying the same property. You can define any color known to man with either HSL or RGB.
PIXEL ASPECT RATIO
Pixels are, once again, quadrilaterals. The pixel aspect ratio, then, is just the property that defines the width:height ratio of the pixel information used to create the image.
For various reasons, it used to be common for video to have non-square pixels. The most practical reason for this is efficiency. To fill a 16:9 Full HD display, you need 1920x1080 pixels with a square aspect ratio (1:1). But by using rectangular pixels with a pixel aspect ratio of 4:3 (1.333), creators could fill the 16:9 image area with only 1440x1080’s worth of pixels; only 75% as many. These files were almost always displayed on screens that had square pixels, however, and the pixels on the screen would usually reflect whichever the dominant pixel was on any given space.
If that’s confusing to you, then I’ve got some good news: pixels are just square now. Meaning that the pixel aspect ratio of almost all photo and video is 1:1, which is also written like (1.0). The days of needing to use non-square pixels for the sake of efficiency have passed. Lucky us.
Keep in mind, too, that so far we’ve been talking mostly about the pixel aspect ratio of the images themselves. All modern displays, such as televisions, computer screens, phones, tablets, etc, display using square pixels.
An image pixel and a display pixel aren’t exactly the same thing, but operate in practically the same fashion. After all, an image pixel is more or less theoretical until it’s displayed on a screen, at which point it’s actually represented by a display pixel.
Compared to things like pixel aspect ratio, resolution is fairly simple and straightforward concept. It’s simply however many pixels there are wide by however many pixels there are tall.
While the concept is simple, there are a lot of various resolutions that we run into in our daily lives. Here are some of the current resolution standards of digital video, and where you might find them:
1280x720 (16:9) - This is the original ‘HD’ (‘High Definition’). The majority of cable channels in the US are broadcasting in 720p. Also, Twitter and Facebook videos.
1920x1080 (16:9) - Full HD (FHD). This is how the bulk of video is seen by most consumers. Netflix, YouTube, Hulu, etc. Also, Blu-Rays!
2048x1080 (17:9) - DCI 2K. Digital Cinema Initiatives standard for 2K theater display. Standard theater showings are some variation of this standard.
2560x1440 (16:9) - 2.5K. It was leap-frogged for UHD, but is still a noticeable stepping stone up from Full HD. YouTube creates 2.5K versions of all uploads that are this resolution and higher.
3840x2160 (16:9) - Ultra HD (UHD). YouTube, Netflix (with paid upgrade), and 4K UHD Blu-rays.
4096x2160 (17:9) - DCI 4K. Digital Cinema Initiatives standard for 4K theater display. Digital IMAX showings are some variation of this standard.
5760x3240 (16:9) - 6K? Who knows yet what this might be called, but it will surely be pushed on us eventually, even if we don’t ever need an increase in delivery resolution.
6144x3240 (17:9) - DCI 6K. Digital Cinema Initiatives future standard for 6K theater display?
7680x4320 (16:9) - 8K? Enough consumers seem to be clamoring for it that companies will make TVs and cameras for it, even if we can’t see in 8K.
Aspect ratio of the overall image is another straightforward concept. It’s simply the ratio of the image width to height, often reduced to the smallest common denominator or other convenient metric. The resolutions listed in the previous section all have the aspect ratios listed in parentheses.
Photographic film and most digital camera sensors are 3:2 ratio. Microsoft also prefers this aspect ratio for their modern Surface products.
Old tube televisions and computer monitors were 4:3 ratio. Televisions first adopted this aspect ratio to closely match films of the time. Silent films were made in 4:3. Upon the creation of motion pictures with sound, the ‘Academy Ratio’ was born (1.375:1), which was still quite close to 4:3. This remained the standard film aspect ratio until the early 1950s, when widescreen aspect ratios became all the rage. Televisions kept their 4:3 aspect ratios, however, and ultimately led to early computer monitors taking the same aspect ratio. The advent of the flat, widescreen television brought about the death of 4:3 television and programming. And once televisions made the switch to a widescreen format, most computers did, too.
The vast majority of modern televisions are 16:9. There’s not nearly as much consistency across phones and tablets, but 16:9 is the standard from which most manufacturers don’t deviate too far.
Somewhat recently, as Instagram became immensely popular with the general public, there was a movement where many people were looking at 1:1 aspect ratio as a happy compromise between 16:9 landscape media and 16:9 portrait smart phones. And then they allowed portrait and landscape photos in the app, killing any momentum the 1:1 movement had. Good job, Instagram.
As for any sort of narrative application to aspect ratio, there’s this:
When you start talking film and video, otherwise known as motion pictures, you have several images happening per second (mated to audio tracks).
The number of images recorded or displayed per second - the frame rate - can drastically affect how those images look and feel. Generally speaking, the higher the frame rate, the more ‘natural’ and ‘life-like’ the footage will feel.
The final delivery destination, or distribution method, has conventionally dictated the frame rates used in making motion pictures.
Movies and film have long had two ongoing standards. The first is a frame rate of about 24 frames per second. This is the standard in the US and much of the world outside of Europe. The other standard, primarily in Europe, is 25 frames per second. So people who are after that ‘film look’ often shoot in 24fps, because it gives the familiar motion cadence of a film.
Animated films typically use some fraction of the total frame rate in creating animations. Depending on the budget and importance of the character and action, any given animation might be created at 12fps, 8fps, or even 6fps; but keep in mind the actual film is still displayed at 24fps. The lower the frame rate, the choppier the overall look of the animation will be. A 12fps animation displays each frame of animation for 2 frames, an 8fps animation displays each animation frame for 3 frames, and so on. Occasionally, stretches of animation might be done in full 24fps, but budget and resources often limit this to very important actions and scenes, if at all.
Television - cable, satellite, and over-the-air - has conventionally been broadcast at 30 frames per second in much of the world. In Europe, the television standard is the same as the film standard, 25 frames per second. Many television channels have now switched to 60 frames per second, which is especially beneficial for sports broadcasts. In Europe, the equivalent is 50 frames per second.
Video game consoles and computers display in 60 frames per second, although some games still operate on a 30 frames per second timebase.
Technically speaking, the reason for the difference in European frame rates compared to the US and much of the rest of the world is due to the power system. Much of the world operates on a 60Hz electrical grid, meaning the alternating current goes through a full cycle in about 1/60th of a second. In Europe, their grids are a 50Hz standard, translating to an alternating current cycle of about 1/50th of a second. As it relates to electronics, this affects the frequency at which they operate and perform major tasks. Screens in the US have a ‘refresh rate’ at some interval of these cycles, so usually 60Hz or 120Hz. In Europe, it’s usually 50Hz or 100Hz.
Operating at 60Hz makes it easy for a screen to display motion pictures at 30fps or 60fps, but what about 24fps? 24 isn’t a common factor of 60, so there has to be a bit of technical wizardry to display a 24fps motion picture on a screen that refreshes every 1/60th of a second. This wizardry is called a 2:3 pulldown, which basically takes 4 of the 24 frames, and turns them into 5 frames, ultimately displaying the 24fps motion picture at 30fps without noticeably affecting the motion cadence of the film. Screens are able to do this instantly and seamlessly. In reality, most people never really view anything at 24fps on their televisions or computers, as everything has had a 2:3 pulldown applied and displayed at 30fps.
The fact that most people view motion pictures through the internet nowadays simplifies these conventions. Whereas other distribution methods like film, television, and video games all have their conventionally designated frame rates, web browsers are free to display any frame rate up to the refresh rate of the computer, which is typically 60Hz (60fps). In other words, YouTube and similar sites support motion pictures that are 24fps, 25fps, 30fps, 48fps, 50fps, and 60fps; side-by-side and without fuss. How does this affect the content creators? You are able to choose a frame rate based on the aesthetic of the motion cadence rather than being forced into a frame rate due to the distribution method.