Why is this PNG mis-colored on Linux?

Question

My site uses a PNG for a transitional background. Here is the site on Firefox on Mac, and here is the same site on Firefox on Linux.

As you can see, the PNG background displays in a duller green on Linux. Is this due to the gamma correction issues described here? How can I solve this problem? I have tried using a JPG and also a BMP, but the image then just always displays in the dull green across all platforms. I want to always show the vibrant green as in the Mac screenshot. Is this just not possible?

Answer 1

Seems to be more of a MAC issue to me, it renders the same in Firefox, Chrome and Opera here under Linux.

The last color of the image is #6f9f00(loaded in GIMP, there's no color profile on it) while the background color is #5FA700 which is waaaay off. Also the screenshot you took under MacOSX has a color profile attached to it, both Firefox and GIMP render it exactly the same as the one you took under Linux.

Also note that on Macs the default Gamma is higher then on windows/linux, which might explain while the background green looks 'dull' to you on other systems, while it's in reality simple brighter on your system.

So my guess is that Safari applies gamma correction to the image but not to the background color, therefore the image is displayed the same way as it would be displayed on other systems, despite the higher gamma value on your Mac, but the background color is not "corrected" and therefore shows it's real value on non Macs which, in this case, is just ways off from the actual value of the image.

So, how to fix it?
Make sure to use #6f9f00 as the background color of the site and adjust to that, and check the color profile settings of your image editing application(I suppose you're using Photoshop) to ensure that there is no profile on the PNG image.

PS: Thank Apple that they deliver you brighter colors than usual :O