<p><a href="https://www.instagram.com/reel/DBzjm20uO3g/" rel="nofollow noreferrer">https://www.instagram.com/reel/DBzjm20uO3g/</a></p>
<p>In this video we see rapidly flashing horizontal black lines. But some of the lines appear red, green, yellow or blue.  Why? The effect disappears when you slow it down.</p>
<p>My investigations: I've tried searching for this illusion but can't find anything besides the link above. I don't have any expertise here and I don't know any mechanism by which something completely black and white can be experienced as having colors.</p>

CC BY-SA 4.0
2024-11-25T05:03:08.010Z
Related, but not a duplicate: [Quantifying chromatic adaptations made by the brain](https://psychology.stackexchange.com/q/12393/4622).
Jiminy Cricket.
CC BY-SA 4.0
2024-11-25T05:05:00.013Z
Welcome Keej. Please take our [tour] and refer to the [help] as and when, but particularly the [ask] section. One of the things we like is that questioners show their own investigations into a topic when posting, you can use the [edit] button to add yours with links where appropriate.
Jiminy Cricket.
CC BY-SA 4.0
2024-11-26T20:08:09.983Z
Edited, thanks.
keej
<optical-illusion>
How can flashing horizontal black lines appear colored?
keej
# How can flashing horizontal black lines appear colored?

(Asked by: username_0 on 2024-11-25)

<https://www.instagram.com/reel/DBzjm20uO3g/>

In this video we see rapidly flashing horizontal black lines. But some of the lines appear red, green, yellow or blue. Why? The effect disappears when you slow it down.

My investigations: I've tried searching for this illusion but can't find anything besides the link above. I don't have any expertise here and I don't know any mechanism by which something completely black and white can be experienced as having colors.

**Tags:** optical-illusion

> **Comments:**
> **username_1**: Related, but not a duplicate: [Quantifying chromatic adaptations made by the brain](https://psychology.stackexchange.com/q/12393/4622).  
> **username_1**: Welcome Keej. Please take our [tour] and refer to the [help] as and when, but particularly the [ask] section. One of the things we like is that questioners show their own investigations into a topic when posting, you can use the [edit] button to add yours with links where appropriate.  
> **username_0**: Edited, thanks.  

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## 0 answers

