//THIS PAGE HAS PROBABLY TO BE CORRECTED FOR 

10.6. 'SNOW LEOPARD', 

WHICH CHANGED INTERNALLY THE GAMMA FROM 1.8 TO 2.2 .. 

UPDATE FOLLOWS, WHEN TESTS FINISHED//

To make a long story even longer:                                                                    

What the colleagues in the FinalCutPro section of AD discussed endlessly, now happens to us, the hobbyists: 

The Gamma Problem.

Gamma is.. in my own words.. well, to begin with.. look, from this side.. easy, it's.. ahh, c'mon, read on your own: http://en.wikipedia.org/wiki/Gamma_correction 

confused?

to quote wiki, in regards to that b/w pic on the right: 

"… Gamma correction demonstration: Each panel shows the display gamma that the pixel values have been adjusted for; for example, the pixels in the second panel are proportional to intensity to the 1/2 power, so the image looks approximately correct on a typical PC monitor. …"

still confused?

me too.- I guess the important line in that article is: 

"… In most computer systems, images are encoded with a gamma of about 0.45 and decoded with a gamma of 2.2; a notable exception, until the release of Mac OS X 10.6 (Snow Leopard) in September 2009, were Macintosh computers: they used 0.55 and 1.8 respectively. …"

Which means: most parts of the industry calculate with 2.2. ...- iMovie users are 'calibrated' to 1.8. … and what happens in detail in the workflow of iM09 … I donno, but it is obviously, that something happens, which I  don't like - loss in quality.

Can we correct that?

Sure. There's a Poor Man's Gamma Correection, and there's a best-practice solution… 

On this website, the solution is, to manually lower brightness.. that is VERY simple, but effective.

aside: BT is talking about h264 encoding, we are talking about AIC: AIC is the intermediate codec of iM, h264 is a delivery codec. But, the Gamma Problem occurs on IMport.. 

the QTengine allows Brightness control, iMovie, QT-based, let us correct brightness on EXport.

But what is best practice?

Gamma is 'a little' more than only a brightness correction ...- it defines the distribution of values between plain white and black, resp. the three basic colors Red, Green and Blue... 

source: http://en.wikipedia.org/wiki/Gamma_correction

source: me … 

notice the Gamma Curves, this is much more than 'Brightness' ... - we need a GAMMA CORRECTION. 

… and, to make things even more complicated: QT has no 'Gamma slider'!

But there's hope, there's Jan E. Schotsman, and there's his tool: JES Deinterlacer!