A photograph is visually high in definition it provides an iconic representation of something in reality. The camera cannot leave anything out because it takes in all light that is reflected at it. A photograph is an example of a hot medium because it extends the sense of vision in high definition. Nothing is left for the user to fill in.
A comic illustration on the other hand is a cool medium. While it is similar to a photograph, it is hand drawn by a person. The person cannot fill in all features, especially in an illustration of a person. Only enough information is provided that a person can fill in other details in order to determine who the person is. This makes a comic illustration high in participation. Since it is also low in definition, the comic illustration is a cool medium.
The concept of hot and cool media has met some controversy. William P. Dommermuth tested the concept scientifically. He tested four groups of university students with four different media. Afterwards he tested their knowledge since McLuhan asserts that learning comes easier from cool media. Dommermuth found that no one medium was better than the rest (Dommermuth, 1974). This suggests that McLuhan's concept of hot and cool media is not a very strong argument.
John K. Mackenzie also poses problem to the concept in his essay. "What will happen when (or if) we have three-dimensional color television with a resolution of 3,000 lines as compared with the two-dimensional 350 line display of standard receivers?" (Mackenzie, 1967). Mackenzie answers his question with the possibility that this new television will be considered a new medium and therefore it won't be classified as television, thus removing the problem of television fitting into the spectrum of a hot or cool medium (Mackenzie, 1967).
Since there is many gaps in the theory of hot and cool media, it would seem that hot and cool are relative to the two media formats being compared. An example of this is the computer monitor. It works exactly like a television monitor in that it is a mosaic of dots that must be put together by the audience. The problem occurs when comparing two different monitors. If one monitor is set at a low resolution, and the other is set at a high resolution, then the computer monitor fits as a hot medium and a cool medium if the two monitors are compared relative to each other. This is where the controversy comes into play since the concept of hot and cool media seems to be dependent the comparison of the two media.