Reading #4

by Carl Bergstrom and Jevin West

In this article we explore a basic rule for the design of data graphics, the principle of proportional ink. The rule is very simple: when a shaded region is used to represent a numerical value, the area of that shaded region should be directly proportional to the corresponding value. In other words, the amount of ink used to indicate a value should be proportional to the value itself.

→ Read the full article at

Response Questions 3-20

• Clearly there are many ways to make data visualization misleading, but often this is a result of making a graph more visually enticing. Part of a designer's job is to appeal to viewers, and without certain visual trickery this can be a tall task. How can a designer work between these two ideas, particularly with data sets that do not lend themselves to visually intriguing representation?

•How literally should we interpret the principle of proportional ink? The author does not leave much wiggle room, but in some of the examples it seems a bit silly to completely submit to this principle. In the 3D bar graph, for example, the extra ink on the sides of the bar do not really have an effect on the perception of the bars' height. Is it really that important to maintain an exact ratio of ink to the data's values?

• Is it a generally good idea to avoid bubble charts? Particularly those that compare 3/4 variables at once? It seems like these tend to cause more trouble than they are worth, especially when they are static.

The Principle of Proportional Ink

Reading Response: by Jonathan Melendez Davidson

  1. I can help but wonder how much of this is just purely 'masturbatory'? I do agree that the ink has to equal the value being represented but when the article commences talking about the perspective of the 3D bar chart and how it doesn't represent the exact value of the chart in those cases I truly wonder if general audience would actually see a difference, better yet understand a difference.

  2. What if the Data sources available are not 100% true. Seeing these examples and reading this article they represent and try to communicate the reality of one specific set of data. Well what if that data is wrong, what is the point of representing it correctly? What if there are multiple data sources which all have different numbers, then which one do we select as designers to represent?

  3. This article is giving me a feeling of what their ideal view of the designer is. "the medium through which data (#'s) are translated" as if the designer were sort of this automata without pre-existing constructed biases and opinions. I say this respecting the act of communicating the 'real' and/or factual information, but this translation from # to visual is already an abstraction which doesn't necessarily lie but truly are just an abstraction of the reality which they represent, a language by which to communicate. IDK this is more of a rant than a question but ... (tbd)

Chloe's quetions

  1. It's interesting to think about volume in terms of charts. How can we use shapes other than rectangles to work with these ideas?

  2. How can we use typography to guide alongside shapes in an inclusive rather than intrusive way.

  3. It is interesting to see how easy it is to manipulate what is presented in data visualisation? perhaps it is often used in a misleading way to benefit marketing?

1. In the line graph figure, the decline appears more substantial than it actually is because the axis does not go to 0 (therefore, the line looks steeper). If that is the case, why does the idea of “proportional ink” matter?

2. If a donut chart uses a track style graph that has more length on the outer rings, when would such a chart be effective and accurate?

3. When/is it ok to sacrifice accuracy for more effective visual perception?

The Principle of Proportional Ink 3:Q's

  1. Are these charts and graph meant to be read for accurate information or for a larger takeaway from the data which can be described in greater detail through writing?

  2. The author didn't make a strong case against "compensat[ing] for this bias in human perception." he gives an example of a poorly done bubble chart, but this doesn't discredit an attempt at altering the formal structures to convey the data accurately to perception (which is the entire point of this article).The concept of Proportional as the ultimate truth seems limiting, as if there is "a" truth or correctness in the presentation of information. Why wouldn't you make information perceptually accurate over "Proportional inked"?

  3. The "ink" metaphor seems archaic in this conversation, as it alludes to a method of displaying information that is static set and represented via the area of "color" or lack of "color", but this information could be represented through a variety of means such as light, sound, interaction, or movement. Why did he choose to use ink over Proportional Representation?