Yesterday, I posted some of my frustrations with how color display behavior got a bit wacky when I hooked up a non-Apple external monitor to my MacBook Pro.
Responses varied from, “I’ve seen this too and I feel your pain” to “Hey noob, don’t expect different monitors to display colors the same.” Thanks to all of you who have shared helpful suggestions on calibration and so forth.
But I failed to convey what was happening, and as I set about clarifying it, things got weirder.
So, here’s a PNG image that shows what I occasionally see: Terminal.app rendering what should be the same color differently on the same display:
I included this image in my original blog post, and “Lew Z” posted this comment:
When I mouseover your 2 terminal text examples, in DigitalColor Meter I get:
Red: 0
Green: 65535
Blue: 0For *both*. As far as the OS knows, and what is displayed on your webpage, they are the same color. If you (and maybe I) perceive color differences between the two, it is a physiological issue of how the eyes and brain perceive color when surrounded by different colors (in this case, your window title bars).
This confused me greatly as when I sampled the image, the colors came out as #00FF00 and #7EF41D. Fortunately, right next to me is another identical hardware configuration I can replicate this on: MacBook Pro (15″ instead of 17″, but ordered weeks of each other and same generation, etc.), same OS X version, same Dell display with the same color profile, same versions of the web browsers. So I pulled the image up on that machine and…
…the colors were identical!
It appears that the PNG has some color profile information in it that’s interfering here, so I saved out a GIF version of what I see on my system:
Obviously, the GIF format will dither the colors, etc. but it does convey that the colors are significantly different. On Dion’s system, the GIF appears exactly as it does on mine.
So here’s what has me profoundly confused:
Why would the same image display differently on the same hardware and the same software with the same settings? I understand why the entire image could display uniformly different to the eye, but why does just part of the image change its actual content?
Anyone know?
