What's the difference between negative and digital?

We often hear the argument between movies and numbers. Nolan, especially the great director, keeps saying that digital photography is not good, and he is still shooting with film today. As we all know, the advantage of digital is that it is easy to modify and restore, and many special effects can be added, so it is not easy to distort when copying or moving. So, why are there so many movie lovers who can even bring the bankrupt Eastman Kodak Company back to life?

What are numbers? The so-called number refers to a basic way of data storage and replication.

Let's imagine first: when you see a sports car parked on the side of the road and want to record what it looks like, but you only have a pen and a piece of paper on you, what can you do? Generally speaking, it is to find a place to sit down, face the sports car and draw the shape of the sports car on paper with a pen. We will use our eyes and feelings to compare the pictures of sports cars on paper with the actual appearance of sports cars, and try to make them more similar. People who have been trained in sketching can draw pictures that are extremely realistic and close to the original, but ordinary people may draw crooked pictures. Is there any way to make ordinary people draw more like it?

In fact, you can also draw crisscross coordinate lines on the paper first, and turn the original white paper into a grid diagram. Then point the grid at the sports car so that the image of the sports car overlaps the grid. Finally, on the grid diagram, all the squares covered by the edges of all sports cars are blacked out. The sports car drawn in this way may have jagged edge, but there won't be too many errors in scale and shape. And as long as the grid is thinner, the image will be more accurate. Assuming that the grid is really fine to a certain extent, even ordinary people can use the first method to draw a sports car map similar to that drawn by professional painters.

The latter method is called number. The former is called analogy (*** og). The biggest difference between numbers and analogies is whether to use this grid drawing method when describing them. This grid drawing method is called quantification and has nothing to do with quantitative easing. Quantized graphics can be recorded in coordinates. For example, "The third row and the sixth column, the fourth row and the seventh column, and the fifth row and the seventh column are all black. This representation is the actual digital data, and the grid sports car map drawn according to this coordinate table is the reproduction of this digital data.

What are the benefits of numbers? Take sports car drawing as an example. The first advantage is that even people who don't know how to draw can draw good works. The second advantage is that no matter how many different squares are used to copy the original sports car map, it will be the same sports car map as long as the number of squares in the vertical and horizontal directions is the same. The third advantage is that the sports car grid can be converted into a coordinate table. Because the coordinate table is composed of a series of words or numbers, it can be transmitted in more ways and is not easy to make mistakes. For example, we can tell each other the coordinate table by phone; Or set up a code table, we can use the light and shade of a flashlight on one hill to send the coordinate table to the receiver on another hill, and the sports car map drawn by the other party according to the coordinate table will still be exactly the same as the sports car map in our hands!

However, this does not mean that analogy is at an absolute disadvantage. The advantage of analogy is also obvious-as long as the painter is strong enough in description, he can draw a sports car map with the same or even higher accuracy in a shorter time than digital painting. Imagine, if we want to draw a sports car that can't see the sawtooth shape, how fine should we set the squares in the grid diagram? This is the reason why the resolution of digital film can't catch up with the details of film for a long time.

To sum up, the various benefits of digital actually refer to the same feature: no distortion. That is to say, no matter how to transfer, compress or change the storage form or storage medium, as long as the resolution (the number of squares in both vertical and horizontal directions) is not changed on the way and irreversible transformation does not occur, a new pattern that is exactly the same as the original pattern can be restored. But it is also because if the original infinite detailed and continuous realistic patterns are quantized into digital data, it is difficult to guarantee that there will be an upper limit of accuracy.

The analogy is that every time you draw with a new piece of paper, it will be a little different from the previous one. It's called distortion. Although it will be distorted, the upper limit of accuracy of analogy method is taken from the medium itself. As long as the appropriate medium is found, the accuracy of analogy method can easily exceed that of digital method. After all, if you want to digitally record the sports car map on a piece of paper, it is obviously unrealistic to draw the squares of the coordinate map as thin as paper fibers or even as thin as molecules.

But now digital technology has developed to make accuracy less and less a problem. Although the accuracy of numbers is still not comparable to that of analogy, human senses usually don't need too precise information, so the accuracy of digital information only needs to be high enough to deceive human senses. Perhaps the most famous technology belongs to Apple's retina screen. Before the advent of this technology, whether it is a computer, a mobile phone or a tablet computer, the human eye can still easily see the jagged edges of words and images, precisely because the grid is not fine enough. However, Apple's efforts in screen manufacturing technology have made the grid spacing on the screen so small that people can't see the sawtooth at normal viewing distance, and we can hardly identify the precision difference between it and actual objects or simulated patterns.

What are the advantages of film? So, why did Nolan and other movie lovers stop filming? If the accuracy of digital film is already the same as that of negative film, what are the advantages of film?

The first is negative feelings. Analog data is a storage method closely related to media. For example, a sports car map drawn by analogy looks obviously different if it is drawn with different pens or different papers. However, if it is a digital record, because the digital data itself is only a series of abstract numbers, it is out of the media. The undistorted feature makes it more "impersonal" or "too real". From recording to screening, only the curtain is made of material, so it is easy for people to feel the so-called "digital coldness". Film is a simulated image produced by chemical methods, so there will be graininess produced by negative particles on the image, which is a kind of noise with material sense. Although the larger the negative particles, the lower the fineness of the picture, but some people like the negative feeling of large particles, because they can feel the material of the film better. This situation rarely happens in digital movies. The same concept can also be applied to vinyl records-although vinyl records tend to produce noise like fried beans, it has become one of the reasons why vinyl lovers like vinyl today.

In addition to the material, the dynamic range of film sensitivity is also relatively large. The so-called dynamic range of light refers to the brightness difference between the darkest place and the brightest place in a picture. The dynamic range of sensitivity refers to the gap that the photosensitive element (film) can capture. If the dynamic range of the scene light exceeds the dynamic range of the camera, it means that the brightest or darkest place in the scene has not been recorded by the camera. This situation is called "overexposure" or "underexposure", which is more directly called "explosion" or "underexposure". The level of explosion image will be much less than that of non-explosion image, which can also be called "relatively flat" and the freedom of dimming explosion image will be greatly reduced in the later stage. Many photographers and lighting engineers who are used to analog photography often feel that their hands and feet are bound when using digital photography, because the picture will "explode" if they are not careful! When using analog photography, you can almost enlarge the contrast of the scene; But if it is digital photography, you usually need to carefully calculate the dynamic range of the scene, unless you use an extremely expensive machine such as Arri Alexa.

Moreover, the format of the film is much simpler. As long as the producer determines the film size, there is basically no need to worry too much about the post-screening. Assuming that the final screening is to make 35mm (35mm) film, it is good to shoot and post-produce with 35mm film. Even if the color is wrong, it can be saved in the end, which will not lead to the problem of not putting it out. The number format is complicated! There are several types of movie files, such as RAW, ProRes 422, H.264 and so on. And you need to know how the project file formats of each editing software and dimming software should be docked and so on. Producers in the film era can shoot first, but producers in the digital era need to know the later process to know what shooting equipment and methods to use when shooting, and can't enter the shooting at will, otherwise they will spend a lot of time and resources on the process later.

Expensive media may be a part that ordinary viewers have never thought of. Why is film a good thing when it is more expensive? In fact, filming itself is an artistic creation, a kind of "performance" performed by actors, photographers and directors. Performance needs a kind of "throwing caution to the wind" determination to show the best of yourself. Because the cost of retaking the mirror in digital shooting is quite low, the creator is relatively easy to take chances and think that retaking is ok even if the performance is not good. Therefore, even if the media of digital shooting is cheaper, it may cause hidden costs of on-site creation and make the performance more conservative. If it is film shooting, the creators will know that the camera is made frame by frame, which is a visible cost, and they will work harder to implement it.