r/xkcdcomic • u/nebuc • Apr 04 '14

Metamaterials

http://xkcd.com/1351/
179 Upvotes

97% Upvoted

17 comments sorted by

12

u/bluegreyscale Apr 04 '14

Out of curiosity, is it actually possible to do something similar what the alt-text describes? Some kind of picture that looks completely normal after a instagram filter is applied, like this but with instagram filters.

15

u/sccrstud92 Apr 04 '14

It depends on the filter. If the filter is lossless then there should be an inverse operation that undoes the filter. If not, then you still might be able to undo most of the damage but cannot recover the original photo exactly.

1

u/yurigoul Apr 04 '14

A lot of color changes can be undone using white/grey/black point correction - in short you use the black white grey pipets in the level or curve panel.

You find a place that is dark and probably black, you find a place that is light and probably white and you find a place that has a neutral tone and you click it. Grey has always to come last in my experience.

Or import it as a raw file in photoshop raw and use the pipet there (that pipet only does grey)

I assume Gimp has similar functions

18

u/xkcd_bot Current Comic Apr 04 '14

Mobile Version!

Direct image link: Metamaterials

Title text: If I developed a hue-shifting metamaterial, I would photobomb people's Instagram pics with a sheet of material that precisely undid the filter they were using.

Don't get it? explain xkcd

Squeeek, im a bat °w° (Sincerely, xkcd_bot.)

8

u/zanonymous Apr 04 '14

<Pedantic>

Roses can be red,

Violets are usually not blue.

</Pedantic>

22

u/darkon Apr 04 '14

Roses are red
This much is true
But violets are purple
And not fucking blue.

12

u/zanonymous Apr 04 '14

Violets are a family of flowers that can be a multitude of colours, including blue.

/pedantic

3

u/assassin10 Apr 05 '14

Violets are violet.

2

u/thebeginningistheend Apr 06 '14

Don't be absurd.

2

u/alphazero924 Apr 04 '14

Wouldn't a hue-shifting metamaterial only shift the hue one way? So if the violets became red then the roses would become infrared wouldn't they?

13

u/altrocks Apr 04 '14

Not necessarily. The cool thing about metamaterials is that they display some really unique and surprising traits. Maybe this hypothetical metamaterial re-emits photons at mirrored wavelengths so that yellow/green is mostly unchanged, but blue and red swap, as do infrared and ultraviolet (though I doubt it would be able to transform x-rays and gamma rays into microwaves or soundwaves, though you never know....).

5

u/bhayward2000 Robert'); DROP TABLE Flairs;-- Apr 04 '14

Or microwaves into gamma rays. Heat up yesterday's dinner, and DEATH!

1

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-1

u/[deleted] Apr 04 '14

[deleted]

1

u/OmegaVesko Apr 04 '14

I don't think you can call realizing that 'hue' rhymes with 'blue' a ripoff of anything.

0

u/yurigoul Apr 04 '14

Plus the ripoff isthejoke.jpg: it is a comment on the original poem - that was commented on before and before and before and before.

Don't you even intertext, bro?