I recently noticed that colors are now displaying darker on iPhone than their actual color values. (Taking an iphone screenshot of an image and using a color utility show that the color values are darker). This seems to be a recent change as I have an iphone screenshot of the same image on OS 3.0. Has Apple changed the iPhone's gamma or is something else going on?
A:
IIRC the iPhone screenshot function saves JPEGs, which utilise lossy compression. The compression might be damaging the colour values.
If you're getting different results on different OS versions it might just be a different JPEG encoder or different configuration of it!
For best results, try taking a screenshot of large area of solid colour (32x32 pixels to be really sure, as JPEG sublocks often go to 16x16 pixels) and checking the colour value of that.
Artelius
2009-10-30 09:10:36
iPhone screenshots are saved as .png files.
iKenndac
2009-10-30 09:16:20
Since when? I could have sworn the iTouch saved JPGs back when I did a bit of web programming for it a while ago.
Artelius
2009-10-30 09:24:37
http://www.ehow.com/how_4605966_screen-shot-iphone-screenshot-app.html seems to agree with me.
Artelius
2009-10-30 09:29:20
In that case this isn't the cause of the problem. I'll leave my answer here in case it helps someone else...
Artelius
2009-10-30 09:36:03
A:
The issue turned out to be one with Snow Leopard. When images are resized in Preview under Snow Leopard, the RGB spectrum is shifted towards red.
Run Loop
2009-11-05 16:45:56