Kumita ← Open visual lesson

RGB vs Grayscale

The code behind the picture

Follow the lesson’s implementation, one code cell at a time.

Choose a language and read the cells in order. These are small teaching examples; the visual lesson runs separately.

Follow the calculation

Same inputs · Same operation · Same result

3 teaching cells · Python standard library · Read-only

1. Prepare the inputs
Four real or demonstration pixels from the lesson: red flesh, a labelled demonstration swatch, green rind and a pale pixel.
In [ ]:
```
import json

pixels = [[240, 6, 56], [90, 70, 123], [27, 166, 85], [255, 255, 255]]
```
2. Combine three channels
The same weighted rule as the visual lesson, rounded. The red flesh pixel and the violet swatch both give 82: different colours, one gray value.
In [ ]:
```
result = [round(0.299 * r + 0.587 * g + 0.114 * b) for r, g, b in pixels]
```
3. Inspect the result
Print the result as JSON so both languages use the same output format.
In [ ]:
```
print(json.dumps(result))
```

Expected result

Running the three cells in order produces this result in either language.