Show HN: The text disappears when you screenshot it

zikero | 126 points

You can take TWO screenshots, moments apart, open in GIMP, paste one over the other and choose any one of these laying modes:

Lighten, Screen, Addition, Darken, Multiply, Linear burn, Hard Mix, Difference, Exclusion, Subtract, Grain Extract, Grain Merge, or Luminance.

https://ibb.co/DDQBJDKR

axiolite | 10 minutes ago

For what it's worth, there are some websites that embed some crazy shit when you screenshot. On reddit, r/CenturyClub will fill your background with a slightly off-white version of your username so that they can identify leakers, and I'm not certain how exactly they do it.

viccis | 4 minutes ago

https://gist.github.com/jncornett/d7cb397ce3ceff268a0ee1b86f...

On iPhone: screenrecord. Take screenshots every couple seconds. Overlay images with 50% transparency (I use Procreate Pocket for this part)

catlifeonmars | an hour ago

This game disappears if you pause it: https://youtube.com/watch?v=Bg3RAI8uyVw

xnx | 3 hours ago

Others have mentioned Branta Games, but I first saw the effect here: https://youtu.be/TdTMeNXCnTs

shannifin | 2 hours ago

I first saw this effect in a video from Branta Games.

https://www.youtube.com/watch?v=Bg3RAI8uyVw

The effect is disrupted by introducing rendering artifacts, by watching the video in 144p or in this case by zooming out.

I'd love to know the name of this effect, so I can read more about the fMRI studies that make use of it.

What I've found so far:

Random Dot Kinematogram

Perceptual Organization from Motion (video of Flounder camouflage)

https://www.youtube.com/watch?v=2VO10eDIyiE

Syntonicles | 3 hours ago

This makes me feel motion-sick, which is kind of impressive because I'm normally not easily susceptible to that.

kemayo | 3 hours ago

Not technically a screenshot, I guess, but trivially easy to do with software I had lying around all the same. https://media4.giphy.com/media/v1.Y2lkPTc5MGI3NjExYXloZ3Z0NT...

alanfalcon | an hour ago

Cool. I used the Windows snipping tool and just screen-recorded it.

vivegi | an hour ago

Has anyone tried a long exposure to see if the motion smears into something discernible? Obviously harder to expose a bright screen without some ND since the shutter speed is the phone's main exposure control

dylan604 | 3 hours ago

Another idea I had with this concept is to make an LLM-proof captcha. Maybe humans can detect the characters in the 'motion' itself, which could be unique to us?

- The captcha would be generated like this on a headless browser, and recorded as a video, which is then served to the user.

- We can make the background also move in random directions, to prevent just detecting which pixels are changing and drawing an outline.

- I tried also having the text itself move (bounce like the DVD logo). Somehow makes it even more readable.

I definitely know nothing about how LLMs interpret video, or optics, so please let me know if this is dumb.

zikero | 3 hours ago

Firefox on Android seems to just be a static image, I can't see any text.

Izkata | 3 hours ago

same thing, but a game: https://brantagames.itch.io/motus

markasoftware | 3 hours ago

Ha cool! How’s it work?

bix6 | 4 hours ago

Fun side effect: staring at the letters for a bit makes the rest of the image move.

altcognito | 3 hours ago

You can also break it by recording the screen, of course.

alliancedamages | 3 hours ago

Had a lot of fun trying to break this. Turns out you can screenshot real easily by zooming out. Maybe there are other ways but I stopped trying :)

cryptoz | 4 hours ago

The text reappears when I screenshot it twice.

kps | 3 hours ago

Seems trivial to diff multiple screenshots to identify what parts move. Or just use a compression algorithm to do the same.

UltraSane | 3 hours ago

Coinbase was hacked for $400M when literally someone from outsourced support services was taking screenshots on their phone!

The culprit had more than 10k photos of all security details for thousands of wealthy customers.

hbbio | 42 minutes ago