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Comment by martin-adams | Hacker News Reader

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martin-adams

I saw an excellent use of this recently here:

https://mobile.twitter.com/SciencePorn/status/63454773027106...

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You should edit your post and remove the "mobile" part from the URL.

Meanwhile, for everyone not seeing what the fuss is about, here's the correct link:

https://twitter.com/SciencePorn/status/634547730271064064?s=...

The mobile link works fine for me.

It doesn't actually do the thing when expanding (for me on Chrome on Windows). Compare what happens when clicking the image between the two.

Huh, Firefox works fine, but Chrome doesn't.

God I hate the trend of putting "Porn" into the title of stuff like this.. stupid

Does it trigger your work firewalls?

Are your government's internet filters too aggressive?

Or do you just have nothing else in life to complain about?

Not OP but I also find it annoying. It triggers my internal NSFW filter. I'm not going to make that risky click at work.

Yes, sorry about that. Unfortunately I've left it too long to edit, so your link will be most appropriate in the thread.

This uses transparency, not gamma correction. A completely different trick.

Funny to see the comments on the Tweet stating it is a transparent png ;)

When I opened it with ImageMagick it appears to be a transparent PNG. Very clever trick, as it seems to use Twitters black background when viewing an image to achieve the effect.

So it's unrelated to the gamma trick in this article?

Yes, it is.

In that case, how does the room disappear?

The room is drawn with translucent black pixels that show up on any light background. The stars are drawn with translucent white pixels that show up on any dark background.

look closely --- it's still there.

That's a different effect. It exploits transparency and the fact that Twitter uses a white background for tweets, but a black background for lightbox images.

I see no difference.

I didn't either, but interestingly on this image and the ones on the OP, if I tilt my laptop screen (Macbook Air) such that I'm looking at it very obliquely I can see the other image..

Someone in the twitter thread said that the image looks different on a black background. When I click the image it shows with a white background, so maybe it looks different on mobile? I put the image on a black background manually and here is what it looks like: http://i.imgur.com/91qsoKy.jpg

Try the non-mobile link: https://twitter.com/SciencePorn/status/634547730271064064

The "Ze first image" looks the same whether displayed in Firefox or with the default "Windows Photo Viewer" on Win 8.1. I did have an apple/peach image that did display differently on the same machine about a year ago.

This example is much more compelling than the ones in the source article—very cool!

Probably because I can't illustrate! Feeding good illustrations like this through my tool should produce equally good results.

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