Even stranger on Windows 8 the thumbnail shows up as an apple but when opened the Windows Photo Viewer shows it as a pear.
Why does this png display differently in Chrome/Firefox than in Safari/IE?
11–20 of 40 posts
Re: Why does this png display differently in Chrome/Firefox than in Safari/IE?
#12Safari on an iPad mini, first edition, shows an apple (obviously) and very faintly a pear.
Re: Why does this png display differently in Chrome/Firefox than in Safari/IE?
#13This reminded me of an old trick that worked in IE6 or so, where they would use alternating pixels to take advantage of how selection highlighting worked in IE6 to make another image appear when you select it.
Re: Why does this png display differently in Chrome/Firefox than in Safari/IE?
#14The the image consists of a checkerboard-style pattern of pixels. The "dark" pixels form the apple image, while the "light" ones show the pear. The answer to the SO question suggests that the gamma correction information (which is used by Chrome and FF, but not by older IE) makes the image darker, blacking out the apple and revealing the pear. Without gamma correction, the apple is visible, and the pear becomes a lig…
Hmm... I'm quite familiar with gamma correction. For those who are not, I recently did an "Explain Like I'm Five" http://www.reddit.com/r/explainlikeimfive/comments/1aeuyb/el...
But, my understanding is that for an image displayed 1-1 pixel-to-screen there is no intermediate math going on. So, there shouldn't be any opportunity for non-gamma-correct calculations to screw up the output.
Here's a nice example of non-gamma-correct browsers producing incorrect results after scaling an image: http://filmicgames.com/archives/354 also http://www.4p8.com/eric.brasseur/gamma.html But, in the SO question there is no scaling. So, I'm still confused about the difference in visual results between different applications directly displaying the image...
Re: Why does this png display differently in Chrome/Firefox than in Safari/IE?
#15Reminds me of this question on JPEG images: http://stackoverflow.com/questions/3937885/cross-browser-inc...
Re: Why does this png display differently in Chrome/Firefox than in Safari/IE?
#16The the image consists of a checkerboard-style pattern of pixels. The "dark" pixels form the apple image, while the "light" ones show the pear. The answer to the SO question suggests that the gamma correction information (which is used by Chrome and FF, but not by older IE) makes the image darker, blacking out the apple and revealing the pear. Without gamma correction, the apple is visible, and the pear becomes a lig…
On my machine I can see both of them, but neither is particularly distinct, as though two 40% transparency images were stacked.
So obviously my various image viewers aren't reading the gamma correction to show the pear, however I'm more curious why I don't see the apple correctly if the image has been intended to show the apple without gamma/color correction?
My monitor is color calibrated, so shouldn't I just see the apple and not the pear?
Re: Why does this png display differently in Chrome/Firefox than in Safari/IE?
#17The the image consists of a checkerboard-style pattern of pixels. The "dark" pixels form the apple image, while the "light" ones show the pear. The answer to the SO question suggests that the gamma correction information (which is used by Chrome and FF, but not by older IE) makes the image darker, blacking out the apple and revealing the pear. Without gamma correction, the apple is visible, and the pear becomes a lig…
Hmm... I'm quite familiar with gamma correction. For those who are not, I recently did an "Explain Like I'm Five" http://www.reddit.com/r/explainlikeimfive/comments/1aeuyb/el... But, my understanding is that for an image displayed 1-1 pixel-to-screen there is no intermediate math going on. So, there shouldn't be any opportunity for non-gamma-correct calculations to screw up the output. Here's a nice example of non-ga…
Even when there's no scaling involved, gamma information embedded in an image can certainly be meaningful. Among other things, they can be used to correct for the fact that different OS's or devices can assume different default gamma factors. Without gamma correction, an image edited on a Mac might look different when viewed on a PC. If the image can tell the browser what gamma factor it was designed for, that problem can be avoided.
Re: Why does this png display differently in Chrome/Firefox than in Safari/IE?
#18Using Photoshop I tried to make my own image like this.
http://i.imgur.com/36EgeOF.png
It's a mix of Tux and the GNU logo. The strange thing is that Firefox shows Tux, and Chrome shows the GNU logo. Very strange considering both Firefox and Chrome show the pear. My understanding is that the GNU logo (the 'lighter' image) should be shown if the gamma correction is applied. Does anyone know what's going on here?
EDIT: By removing the iCCP color profile chunk, the image displays properly in Firefox.
For anyone interested in making one:
First, I put the two images on separate layers in photoshop. I changed the output levels on Tux to be from 0 to 210, darkening it slightly. I changed the output levels on the GNU logo to be from 215 to 255, making it very bright. Then I used a layer mask on the top layer with a grid pattern to mix the two images. The saved image was a mix of the relatively normal Tux pixels and the bright GNU pixels.
The final touch was editing the gAMA value in the PNG. Using the free program, TweakPNG, I set it to something very low, like in the pear image: 0.02. And that was it!
Re: Why does this png display differently in Chrome/Firefox than in Safari/IE?
#19The thing that puzzles me is that the image opens in GIMP showing the apple (incorrectly, apparently). I would have thought that GIMP would be entirely aware of embedded color/gamma information like this. (It certainly makes enough of a fuss about color profiles practically every time I open an image!) Is the gamma somehow encoded in a less-standard way, or is GIMP just less clever than I thought?
(My copy of GIMP is a bit outdated, but that shouldn't be a big deal for a basic feature like this, right?)
Re: Why does this png display differently in Chrome/Firefox than in Safari/IE?
#20Earlier quoted context omitted.
Hmm... I'm quite familiar with gamma correction. For those who are not, I recently did an "Explain Like I'm Five" http://www.reddit.com/r/explainlikeimfive/comments/1aeuyb/el... But, my understanding is that for an image displayed 1-1 pixel-to-screen there is no intermediate math going on. So, there shouldn't be any opportunity for non-gamma-correct calculations to screw up the output. Here's a nice example of non-ga…
Even when there's no scaling involved, gamma information embedded in an image can certainly be meaningful. Among other things, they can be used to correct for the fact that different OS's or devices can assume different default gamma factors. Without gamma correction, an image edited on a Mac might look different when viewed on a PC. If the image can tell the browser what gamma factor it was designed for, that proble…
That's exactly what I was forgetting. Different systems assume different display gammas such as 1.8, 2.2 or sRGB (a mix of 1.0 and 2.4). Thanks!