# Looking for Software to Invert Just Red and Green, Not All Hues

**URL:** <https://boards.straightdope.com/t/looking-for-software-to-invert-just-red-and-green-not-all-hues/338871>\
**Category:** Factual Questions\
**Created:** [January 7, 2006, 7:11am UTC](https://boards.straightdope.com/t/looking-for-software-to-invert-just-red-and-green-not-all-hues/338871 "2006-01-07T07:11:36Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\
**Post date:** [January 7, 2006, 7:11am UTC](https://boards.straightdope.com/t/looking-for-software-to-invert-just-red-and-green-not-all-hues/338871/1 "2006-01-07T07:11:36Z")

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It’s pretty easy to find a way to completely invert the colors of an image.

But I’m looking for a way to invert _just_ the red and green values. So whatever in the image is originally more red becomes instead more green, and vice versa.

Anyone know a way to do this using any freely or cheaply available software?

It turns out about 14 out of every 10,000 people has “pseudonormal vision” which is exactly what I just described: their reds and greens are inverted. But there’s pretty much no way to tell who’s “pseudonormal” without doing a scan of their ocular nerve while they’re looking at stuff, because they, of course, still call red things red and green things green.

So anyway, I just want to see what pseudonormal vision looks like. Anyone know a way? (Assuming I’m not pseudonormal myself of course!)

-Kris

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**Author:** ![DarrenS](https://avatars.discourse-cdn.com/v4/letter/d/977dab/32.png) [@DarrenS](https://boards.straightdope.com/u/DarrenS)\
**Post date:** [January 7, 2006, 7:15am UTC](https://boards.straightdope.com/t/looking-for-software-to-invert-just-red-and-green-not-all-hues/338871/2 "2006-01-07T07:15:56Z")

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How about [Irfanview](http://www.irfanview.com/) ? It’s free, and it seems to do what you want via Image | Swap Colors | RGB -\> GRB

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**Author:** ![TJdude825](https://avatars.discourse-cdn.com/v4/letter/t/dec6dc/32.png) [@TJdude825](https://boards.straightdope.com/u/TJdude825)\
**Post date:** [January 7, 2006, 6:26pm UTC](https://boards.straightdope.com/t/looking-for-software-to-invert-just-red-and-green-not-all-hues/338871/3 "2006-01-07T18:26:59Z")

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I would guess most programs could do it with a little creativity. Maybe if you turn the green and blue all the way down, then find some command along the lines of “Recolor Image, green” Save that, and repeat from the original file, but green-\>red. Extract only the blue from the original image, and recombine all three. Not sure how this would work in practice, but it seems like it ought to be feasible.

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**Author:** ![TJdude825](https://avatars.discourse-cdn.com/v4/letter/t/dec6dc/32.png) [@TJdude825](https://boards.straightdope.com/u/TJdude825)\
**Post date:** [January 7, 2006, 6:49pm UTC](https://boards.straightdope.com/t/looking-for-software-to-invert-just-red-and-green-not-all-hues/338871/4 "2006-01-07T18:49:57Z")

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Using Irfanview:

Original: [http://i7.photobucket.com/albums/y267/letmeentertainu/Drama/Progressive\_Dinner05/100\_1304.jpg](http://i7.photobucket.com/albums/y267/letmeentertainu/Drama/Progressive_Dinner05/100_1304.jpg)  
Inverted: [http://img.photobucket.com/albums/v201/MatrixFrog/100\_13041.jpg](http://img.photobucket.com/albums/v201/MatrixFrog/100_13041.jpg)

So I guess this proves that “white” skin has a lot of red in it. I’m the one in the back, between the two girls, by the way.

Original: [http://i7.photobucket.com/albums/y267/letmeentertainu/Drama/Progressive\_Dinner05/100\_1326.jpg](http://i7.photobucket.com/albums/y267/letmeentertainu/Drama/Progressive_Dinner05/100_1326.jpg)  
Inverted: [http://img.photobucket.com/albums/v201/MatrixFrog/100\_13261.jpg](http://img.photobucket.com/albums/v201/MatrixFrog/100_13261.jpg)

Apparently yellow = red + green = green + red = yellow, so yellow doesn’t change much…

Original: [http://i7.photobucket.com/albums/y267/letmeentertainu/Drama/Progressive\_Dinner05/100\_1321.jpg](http://i7.photobucket.com/albums/y267/letmeentertainu/Drama/Progressive_Dinner05/100_1321.jpg)  
Inverted: [http://img.photobucket.com/albums/v201/MatrixFrog/100\_13211.jpg](http://img.photobucket.com/albums/v201/MatrixFrog/100_13211.jpg)

Sorry all the inverted pictures are smaller than the originals. I think it’s because I saved them as bmp and photobucket converted them to jpg or something.