Digital BW, The Print

I'm still not sure I got that right! I mean, actually your description of
four curves (like with all our favourite worlflows :) does make more sense.
I just wanted to try and get across the point that, whatever the transform
or curve or technique used... this is a 'profiled' transformation and is not
a 'random' transform.

As you say, there are differing points at which the transform could be
applied. If you could conceptualise a 'perfect medium' one set of defined
'dither patterns' will give you up to, say, 10,000 different 'theoretical'
tones. What I would then do with the 'profile' is cut off all the values
that gave too much ink, all the values that left too little ink, or 'dotty'
ink. ie you set your end-points. So with a STANDARD mathematical dither
pattern set, you can set a profile that maybe makes 4000+ available output
tones for each media type. WHen printing, you'd go the other way, you have
the desired output value, use the profile to find out which 'pattern' to
print.

I have no idea!

nij


> -----Original Message-----
> From: Tyler Boley [mailto:tyler@...]
> Sent: 04 October 2001 17:31
> To: DigitalBlackandWhiteThePrint@yahoogroups.com
> Subject: [Digital BW] Re: Dithering THOUGHTS
>
>
> --- In DigitalBlackandWhiteThePrint@y..., "Nij" <nigel@m...> wrote:
> snip
> > One of you mentioned 'curves' and I'd like to suggest that
> using that term
> > is misleading (perhaps not entirely innacurate, but
> misleading). What _I_
> > would do to print greyscale images using quads (using a
> program) is to map
> > 'image tones' to 'output tones' using some kind of map of which
> dither / dot
> > / whatever pattern achieves that tone on a particular media.
> And, that may
> > sound familiar to you - page 6 of the plugin manual shows the
> workflow...
> > and I think this would come under 'QMM'. So, although it's a
> minor point, I
> > see this as a once-off mapping, rather than applying curves to
> channels or
> > anything like that some have used. Just my world view.
>
> Right, I just visualize such mapping as a curve, at least for a
> single channel. O ther cross channel mapping like color
> changes are more than just curves obviously. Any tonal edit is
> such a mapping, if it occurs at the driver level then it may be
> as you suggest. However, Bill has stated the the separation
> curves (each for the paper characteristics) are contained
> within the profiles. Also, I have edited profiles for quad use by
> applying the sep curves to the profile itself (that doesn't
> mean I have any idea how they do it). So how much tonal mapping
> occurs at the dither stage, and how much occurs at the
> profile application stage, is an open question. But yeah... mapping.
> Tyler
>
>
>
>
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