Color themes in Power BI - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Color Theme JSON Structure

Which of the following JSON snippets correctly defines a Power BI color theme with three custom colors named "Primary", "Secondary", and "Accent"?

A { "name": "CustomTheme", "dataColors": { "Primary": "#FF5733", "Secondary": "#33FF57", "Accent": "#3357FF" } }

B { "themeName": "CustomTheme", "colors": ["Primary": "#FF5733", "Secondary": "#33FF57", "Accent": "#3357FF"] }

C { "name": "CustomTheme", "dataColors": ["#FF5733", "#33FF57", "#3357FF"] }

D { "name": "CustomTheme", "dataColors": ["Primary", "Secondary", "Accent"] }

💡 Hint

Look for the correct JSON format where colors are listed as an array of hex codes.

Power BI color themes use the "dataColors" property as an array of color hex codes. Option C correctly lists the colors as an array. Option C uses an invalid key and syntax. Option C uses an object instead of an array. Option C lists color names instead of hex codes.

❓ dax_lod_result

intermediate

Effect of Color Theme on Visual Measure Display

You apply a color theme with the following dataColors: ["#0000FF", "#00FF00", "#FF0000"]. You have a bar chart with three categories: A, B, and C. Which color will category B's bar use by default?

A #0000FF (Blue)

B #00FF00 (Green)

C #FF0000 (Red)

D Default gray color

💡 Hint

Colors are assigned in order to categories starting from the first color.

The first category (A) uses the first color (#0000FF), the second category (B) uses the second color (#00FF00), and the third category (C) uses the third color (#FF0000).

❓ visualization

advanced

Choosing Accessible Color Themes for Reports

You want to create a Power BI report color theme that is friendly for colorblind users. Which color palette below is best suited for this purpose?

A ["#800080", "#008000", "#000080"] (Purple, Green, Navy)

B ["#FF0000", "#00FF00", "#0000FF"] (Red, Green, Blue)

C ["#FF69B4", "#FFD700", "#00FFFF"] (Pink, Gold, Cyan)

D ["#0072B2", "#D55E00", "#E69F00"] (Blue, Vermilion, Orange)

💡 Hint

Look for colors that are distinguishable by people with common types of color blindness.

Option D uses colors from the ColorBrewer palette designed for colorblind safety. Red and green combinations (Option D) are problematic for many colorblind users. Options C and D have colors that may be confusing or low contrast.

🔧 Formula Fix

advanced

Identifying Error in Custom Color Theme JSON

Which option contains a syntax error that will cause Power BI to reject the custom color theme JSON file?

{
  "name": "MyTheme",
  "dataColors": ["#123456", "#654321", "#abcdef"],
  "background": "#FFFFFF",
  "foreground": "#000000",
  "tableAccent": "#FF00FF",
  "extra": { "highlight": "#FFFF00" }
}

A { "name": "MyTheme", "dataColors": ["#123456", "#654321", "#abcdef"], "background": "#FFFFFF", "foreground": "#000000", "tableAccent": "#FF00FF", "extra": "highlight": "#FFFF00" }

B { "name": "MyTheme", "dataColors": ["#123456", "#654321", "#abcdef"], "background": "#FFFFFF", "foreground": "#000000", "tableAccent": "#FF00FF", "extra": { "highlight": "#FFFF00" } }

C { "name": "MyTheme", "dataColors": ["#123456", "#654321", "#abcdef"], "background": "#FFFFFF", "foreground": "#000000", "tableAccent": "#FF00FF" }

D } } "00FFFF#" :"thgilhgih" { :"artxe" ,"FF00FF#" :"tneccAelbat" ,"000000#" :"dnuorgerof" ,"FFFFFF#" :"dnuorgkcab" ,]"fedcba#" ,"123456#" ,"654321#"[ :"sroloCatad" ,"emehTyM" :"eman" {

💡 Hint

Check the JSON syntax carefully for missing braces or misplaced colons.

Option A is missing braces around the "extra" object and has an invalid key-value syntax, causing a JSON syntax error. Options B, C, and D are valid JSON structures.

🎯 Scenario

expert

Designing a Dynamic Color Theme for Multiple Report Pages

You manage a Power BI report with multiple pages, each representing a different product category. You want to create a color theme that automatically assigns a unique color to each category and ensures consistent colors across all pages without manually editing each visual. Which approach best achieves this?

A Use a calculated column in the data model to assign color hex codes and bind colors dynamically in visuals using conditional formatting.

B Manually set colors for each visual on every page to match category colors.

C Apply the default Power BI theme and rely on automatic color assignment per visual.

D Define a custom color theme JSON with a long dataColors array listing all category colors in order.

💡 Hint

Think about how to link data values to colors dynamically and consistently.

Option A uses data-driven conditional formatting, which dynamically assigns colors based on data values and ensures consistency across visuals and pages. Option A requires manual updates if categories change. Option A is tedious and error-prone. Option A does not guarantee consistent colors.