Re: [APML] printing LRGB's

["Mike Cook, AF9Y" <mwcook@concentric.net>]

Hey Tony,

    Sounds reasonable.  Could you post a comparison of the original
and histogram adjusted image?

Mike Cook
AF9Y

From:           	"Tony Hallas" <tonyhallas@foothill.net>
To:             	<astro-photo@seds.org>
Subject:        	Re: [APML]  printing LRGB's
Date sent:      	Wed, 1 May 2002 18:34:03 -0700
Send reply to:  	astro-photo@seds.org

> Hello,
> 
>     I am going to go out on a limb here with something that I chanced upon this morning...
>     I have been trying to get a really nice output from the CCD LRGB's. (or they could be
>     from photo origins... it's not going to matter...) The results looked kind of
>     "plastic"... as in no good. So the first thing I did was print a pure RGB... it came
>     out beautiful! You could not tell it came from a CCD source to save your life. Where
>     was the Luminance messing up the shot?
>      It occurred to me that I should look carefully at the histograms of both... if the
>      histograms are a graph of the number of pixels occupying a certain value, maybe I
>      could learn something from this. There it was... the RGB had most of the values
>      nicely concentrated in the "middle" of the graph, whereas the Luminance went from the
>      extreme left to the edge of the right. What I think was happening was in the LRGB
>      combine, there was no color values for parts of the Luminance... so it came out
>      looking strange. After stretching and compressing the two histograms to look almost
>      identical, the resulting print looked awesome! In fact, it looks like something shot
>      with a much larger telescope than 14.5"... there is now a color value for every value
>      of the Luminance... and the print looks "real" instead of "plastic"...
>       I don't know if there is any merit to this, or if this is a "duh... you didn't know
>       that???" sort of thing... but it sure helps the quality of the print.
> 
>        Tony
> 



Mike Cook, AF9Y
http://www.af9y.com
mwcook@cris.com




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