[Tig] instinctive contrast

[Michael Bittle]

Perhaps, then, the technical description of contrast is not one of  
absolute values (luma ~ x IRE, chroma ~ y IRE) but rather some sort  
of relativistic calculation;

contrast = {red with respect to green} transformed by {green with  
respect to blue} transformed by {blue with respect to red}

  (I'll leave the real equations to real mathematicians)

Mike


On Mar 19, 2007, at 11:39 AM, Rob Lingelbach wrote:

>
> On Mar 19, 2007, at 11:55 AM, Michael Bittle wrote:
>
>>
>> Could it be that what we perceive as contrast is not purely  
>> function of black and white?
>
> yes, I think you're beginning to describe what I was at a loss to  
> explain, that color adds
> something that makes up for a lack of contrast, like your example  
> that a 200Hz emphasis will
> improve the perception of bass.  Description of this by example may  
> be our only recourse,
> as the technical/scientific explanation is elusive.
>
> Joe Owens wrote:
>
> > It is disturbing how casually most black-and-white from colour is  
> achieved by simply
> > turning down the saturation dial.
>
> and this depends on what you mean by disturbing, but I agree.   
> There are some other
> factors of which Richard Kirk's post hinted, for example the  
> interesting halation produced
> by vidicon cameras, which is very difficult to replicate with  
> modern equipment; the
> interesting grayscale (with low contrast!) of kinescope images.    
> As a child I too was
> prevented from watching TV with the room lights down; the patriarch  
> said "it will ruin
> your eyes!"  of course he also thought reading in bed would ruin my  
> eyes, when actually
> it just ruined my sleep.
>
> Instead of removing color from an image and leaving a low-contrast  
> black and white image,
> I think for a moment of adding color to a medium-or-high-contrast  
> black and white image,
> which is done with toning and tinting.  Toning and tinting, done to  
> photographs, (forgetting
> colorization of moving picture film) can be pleasing to the eye,  
> when it is done with
> low or very low saturation.  There is a connection between color  
> and contrast that seems to
> be in some kind of inverse ratio, depending somewhat on the  
> artistic taste of the viewer.
>
> --Rob
>
> --
> Rob Lingelbach
> http://www.colorist.org/robhome.html
> rob at colorist.org  rob at lingelbach.us
>
>