Datacolor User to User Support Group.

With CRT displays, there were controls for both contrast and  
brightness, and the most effective way to avoid clipping at either end  
while doing a visual, not measured calibration, was to adjust until  
the four squares were visible.

For LCDs this is seldom an issue. First, on less expensive displays  
there may be clipping at all settings. And with the types of controls  
on many LCDs, clipping may not occur at any setting. Besides, most  
LCDs have no control to adjust the blacks, and whites on them are so  
bright that luminance is not set to just below clipping, it's ideally  
set way down from full brightness, through a targeted white luminance  
value. Targeted white and black luminance values are measured with the  
Spyder, not set visually.

To put of much more simply: if you don't like making visual  
adjustments, select measured, not visual mode. Then your setting will  
not come from the four visual squares, but from Spyder measurements  
you take later in the calibration process.

C. D. Tobie
Global Product Technology Mngr.
Digital Imaging & Home Theater
Datacolor.com
CDTobie@...

On Feb 13, 2009, at 8:24 PM, Nathan Gutman <nzgutman@...>  
wrote:

> I am still learning... learning...
> Spyder hardware is supposed to eliminate the visual judgment needed  
> when using calibration software such as Adobe Gamma or QuickGamma.
> But when using Spyder I am asked to visually inspect four white  
> squares and four black squares and adjust monitor brightness and  
> contrast accordingly.
> Isn't this predicated on the visual acuity of the observer?
> Can someone please explain?
> Thanks,
> -- 
> Nathan Gutman
>
>
>