Re: Magick-users Digest, Vol 89, Issue 5

Ah fantastic, that second one did it perfectly. Much obliged. 

On 16 Jun 2010, at 20:00, [email protected] wrote:

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>   1. Re: Converting to a single-color image (duotone sans black
>      channel) (Anthony Thyssen)
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> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Wed, 16 Jun 2010 10:22:44 +1000
> From: Anthony Thyssen <[email protected]>
> Subject: Re: [magick-users] Converting to a single-color image
> 	(duotone sans black channel)
> To: IM User List <[email protected]>
> Message-ID: <20100616102244.2bce6538@wraith>
> Content-Type: text/plain; charset=US-ASCII
> 
> 
> On Mon, 14 Jun 2010 21:17:11 -0700
> [email protected] wrote:
> | >Hello,
> | >
> | >Apologies if I'm missing something obvious, I'm trying to work out 
> | >how to convert an image to a single colour - much like grayscale but 
> | >colorised. Effectively what I'm trying to do is replicate the effect 
> | >of Photoshop's Screen blending mode when the top layer is a solid 
> | >color. I've put up an example to compensate for my inability to 
> | >articulate this properly here: http://sho.ch/otterconvert.jpg
> | >
> | >I can do a duotone easily enough but this has me stumped. It would 
> | >also make my life notably easier if it was a single invocation of 
> | >convert.
> | >
> | >Any guidance would be greatly appreciated.
> | 
> | 
> | see -tint and related techniques at 
> | http://www.imagemagick.org/Usage/color/#tinting
> | 
> | also if you are on unix, see my script tintilize at 
> | http://www.fmwconcepts.com/imagemagick/index.php
> | 
> | 
> | Fred
> | 
> | 
> | P.S.  On second thought after re-reviewing your example, a better 
> | method would appear to be
> | 
> | +level-colors blue,white
> | 
> | see http://www.imagemagick.org/Usage/color/#level-colors
> 
> Note you should greyscale the image first then apply +level-colors
> 
> Remember +level-colors is still a -level operator, just getting its
> values (+level -> map black and white to given levels) from the colors
> you have specified.  each channel will still be modified individually.
> 
> So use...
>   -colorspace Gray +level-colors blue,white
> 
> You can also use -gamma afetr the -colorspace operator to adjust the
> mid-tone brightness, if you want to.
> 
> 
> 
>  Anthony Thyssen ( System Programmer )    <[email protected]>
> --------------------------------------------------------------------------
>           Base 8 is just like base 10 really...
>                   ...if you're missing two fingers.    - Tom Lehrer
> --------------------------------------------------------------------------
>   Anthony's Castle     http://www.cit.griffith.edu.au/~anthony/
> 
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> End of Magick-users Digest, Vol 89, Issue 5
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