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A comment on DarkJPEG. Parent comment

Re:DarkJPEG by nitrogen on Monday July 22, 2013 @11:45PM (#6088121)
also, something like tineye can be used to retrieve web-sourced images for comparison, which would make any hidden data really obvious (and a smooth gradient would be even more suspicious if the lowest bits weren't smooth).

Smooth gradients are only smooth if you add noise to the lower bits, due to having only 256 color levels per channel. A comparison: http://imgur.com/0cJWm8t

Those color bands are indeed only one color value apart per channel; the first visible band is rgb(50, 120, 50), while the second is rgb(51, 119, 51).

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Re:DarkJPEG by anonymous on Tuesday July 23, 2013 @07:09AM (#6089269)
The banding is almost imperceptible though. I had to get close to the monitor and squint a lot to see it.
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Re:DarkJPEG by andrewcooke on Tuesday July 23, 2013 @08:42AM (#6089616)
oh, good point. the site should explain this for people like me and also clarify how many bits are available.
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