[Tig] "subtractive" saturation - does it look better?

Bob Friesenhahn bfriesen
Fri Mar 3 17:28:18 GMT 2006

Thanks to oktobor for supporting the TIG
> I think images from both bad lenses and excellent lenses would benefit from
> more contrast. Perhaps images from bad lenses would benefit more, but I
> think that is overshadowed by the other factors (adding more contrast just
> seems to make an image pop and have more life to it).
> I'm not sure exactly why more contrast adds pop/life to an image, but one
> theory I have is that more contrast makes an image less ambiguous. Our
> eyes/vision can better guess illuminance and lightness of the surfaces it
> sees.

There is an ideal amount of contrast.  With too much or too little 
contrast, the viewer soon becomes tired.  With the right amount of 
contrast the viewer sees a pleasing image without becoming tired.

A good analogy is in a sound reproduction system.  It is well known 
that the quality of the tweeter has a huge impact on sound 
reproduction.  With an excessively bright tweeter, the listener hears 
"everything" (can hear a pin drop!) but the sounds is artificial and 
the listener soon becomes tired.  With an excessively dull tweeter, 
the production sounds lifeless and the listener becomes 
disinterested.  Regardless of the effect if tweeter quality on sound 
reproduction, we also know that midrange is extremely important since 
that is where most sounds (e.g. human voice) are heard and a lack of 
clarity in the midrange area leads to poor intelligibility.

Applying this analogy back to images, we see that the "tweeter" is 
like detail definition, and that the "midrange" is like overall image 
levels and color saturation.

Bob Friesenhahn
bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/

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