Re: [CinePaint] Really basic script for batch converting.

On Mon, 30 Nov 2009, [email protected] wrote:

> I have one last question, :-) concerning a previous mail about adding
> 0.008 value of noisify to an 8bit image in Cinepaint.
>
> Bob I think you gave a command line option for GraphicsMagick something
> along the lines of ... -operator noise-Guassian '6.5%' ...

I don't know how Cinepaint's noise is scaled.  I assume that 0.008 is 
two 8-bit 'counts' of noise (+/- 1 count) and that it would be similar 
to a specification of "0.8%" for GraphicsMagick.  This is of course a 
very small amount of noise and if you can take a video signal, add two 
'counts' of noise, and then see the noise, you have vastly better eyes 
than I do.  Note that "0.8%" of specified noise produces noise which 
falls within +/- 1 count at 8-bits and that if the image is saved to 
8-bits (e.g. most computer displays are 8 bit) many noise samples will 
not be represented at all since many will be less than 0.5 count.

> I'm successfully compositing in GM, ie: adding a second layer to an image
> in order to apply noise but when using the GM noise option above nothing
> seems to be happening, on flattening the image it still exhibits gaps to
> the histogram when doing a HSL edit in CP, where doing this procedure in
> Cinepaint with noisyfy doesn't.

I am not sure exactly what Cinepaint's noisyfy does, or what exactly 
"HSL edit" entails so hopefully someone with knowledge of Cinepaint 
internals can comment here.

> Should I be using +noise command, if so, i can't find what the 'value'
> should be to be approx equivilent to Cinepaints 0.008 noisify. Even low
> values are vastly more noisy than noisify, which at 0.008 I have to have
> zoomed the image x16 to see the effect.

The +noise command is a legacy ImageMagick operation which only 
produces "100%" noise.  The same noise generator is used but there is 
no scaling factor.

Bob
--
Bob Friesenhahn
[email protected], http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/

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