screenGamma

[jrioux]

I have a new iMac (Intel Core i5) which I've been using to generate pngs via a 3D raytracing program. The images look good on the development computer, and on the Livecode program running on the home computer, but when I run the app on another Mac, the images come out looking much lighter (not good). I tried adding a slider to manually set the screenGamma, but it does not seem to be having any effect (no visual difference between setting the screenGamma to 3 or 1 or anywhere in between). I can recall writing programs that used such a manual setting before, and they worked fine. It is Mac? Is it Livecode? Is it Snow Leopard? I would like not to have to render my images differently for different target machines.

[wsamples]

Resulting from the unique interaction of hardware, software and the personalized settings of the user, these differences are inevitable as you move from machine to machine. There's a market for color profiling and calibration software and devices costing into the hundreds of dollars for a reason! There may be problems caused by differences in blackpoint and whitepoint as well as gamma settings. Livecode's "screenGamma" does work and could be used to offer some level of adjustment. You can read the current value as well as set it. The dictionary makes it clear that the image needs to be reloaded after the setting is changed or you won't see any effect. I just tried it here in OS X, Windows and Linux and it does work, although there's no guarantee it will solve every display issue

Good luck!

[Klaus]

Since this only applies to PNG files, I would use JPEG files, if possible!

Apple change its factory screen gamma in OS 10.6(?) from the correct and standard! value 1.8 to
the incorrect non-standard 2.2, which has been used in Windows forever, go figure!

So maybe the other machines you tested happen to run 10.5x?

Anyway, stick with JPEG (or TIFF with alpha channel if nedessary)!


Best

Klaus