# Is there a way to get the complimentry colour of a RGB hex value?

**URL:** <https://boards.straightdope.com/t/is-there-a-way-to-get-the-complimentry-colour-of-a-rgb-hex-value/511555>\
**Category:** Factual Questions\
**Created:** [September 25, 2009, 6:57pm UTC](https://boards.straightdope.com/t/is-there-a-way-to-get-the-complimentry-colour-of-a-rgb-hex-value/511555 "2009-09-25T18:57:32Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![Bisected8](https://avatars.discourse-cdn.com/v4/letter/b/a4c791/32.png) [@Bisected8](https://boards.straightdope.com/u/Bisected8)\
**Post date:** [September 25, 2009, 6:57pm UTC](https://boards.straightdope.com/t/is-there-a-way-to-get-the-complimentry-colour-of-a-rgb-hex-value/511555/1 "2009-09-25T18:57:32Z")

</div>

Basically if I had a colour as a hex value (we’ll just use #XXYYZZ with the two letters representing the hex or the decimal values), is there some sort of algorithm (or failing that a more organic method) I could follow to get its complimentry colour?

---

<div class="post-metadata">

**Author:** ![Lobohan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lobohan/32/79_2.png) [@Lobohan](https://boards.straightdope.com/u/Lobohan)\
**Post date:** [September 25, 2009, 7:26pm UTC](https://boards.straightdope.com/t/is-there-a-way-to-get-the-complimentry-colour-of-a-rgb-hex-value/511555/2 "2009-09-25T19:26:02Z")

</div>

If you have Adobe Illustrator you can set the fill color to the hex value and then select the _Color Guide_ palette and change the drop down to _Complementary_.

That will give you the compliment and if you want any other color harmonies based on it.

---

<div class="post-metadata">

**Author:** ![Bisected8](https://avatars.discourse-cdn.com/v4/letter/b/a4c791/32.png) [@Bisected8](https://boards.straightdope.com/u/Bisected8)\
**Post date:** [September 25, 2009, 7:31pm UTC](https://boards.straightdope.com/t/is-there-a-way-to-get-the-complimentry-colour-of-a-rgb-hex-value/511555/3 "2009-09-25T19:31:05Z")

</div>

I use Fireworks, which doesn’t seem to have that tool. In any case, if there’s a way to do it manually (i.e. in my head or with a pen and paper), it would probably be better if I used that, since I sometimes end up using paint.

---

<div class="post-metadata">

**Author:** ![picker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/picker/32/13969_2.png) [@picker](https://boards.straightdope.com/u/picker)\
**Post date:** [September 25, 2009, 7:50pm UTC](https://boards.straightdope.com/t/is-there-a-way-to-get-the-complimentry-colour-of-a-rgb-hex-value/511555/4 "2009-09-25T19:50:29Z")

</div>

try this site for a decent tool: [http://websitetips.com/colortools/sitepro/](http://websitetips.com/colortools/sitepro/)

---

<div class="post-metadata">

**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\
**Post date:** [September 25, 2009, 7:52pm UTC](https://boards.straightdope.com/t/is-there-a-way-to-get-the-complimentry-colour-of-a-rgb-hex-value/511555/5 "2009-09-25T19:52:21Z")

</div>

According to [this site](http://serennu.com/colour/rgbtohsl.php), you have to first convert RGB values into HSL and then add/subtract 180 degrees from the hue.

Or [their calculator](http://serennu.com/colour/colourcalculator.php) can do it for you.