Digital BW, The Print

Thank you, Lou,

What you say, makes sense.  I could see the diff'  between direct grayscaling and running 
100% red in the channel mixer, but I thought that was because Photoshop was 
automatically adjusting for the luminescence values. 

I assume from what you are saying that Photoshop has some set ratio(possibly 30%R, 
60%G and 10%B)  However, If one wishes to modify the results he can use the channel 
mixer.  It would be good to get the actual percentages from Adobe so that we would all 
know the actual percentages without guessing. 

Well, they don't call Photoshop the most complicated software system on earth for 
nothing.  I thought the 'learning curve' would flatten out after a while. :-)

Lincoln

 
> Lincoln,
> 
> Channel Mixer simply defaults to 100% of the red channel upon opening,
> but that doesn't mean it is the default B&W conversion formula for
> Photoshop.  When you click 'grayscale' in Channel Mixer, it just jumps
> to the first available channel, which is red, and leaves it at 100% so
> you can start fiddling around with the sliders.  That gives you a
> display of the Red channel only, with both Green and Blue channels set
> to 0%.  It's just a blank canvas and a starting point.  
> 
> Looking at any grayscale conversion using Mode>Grayscale, you can see
> that the result is not the Red channel only.  All the information I
> can find suggests 30%R, 60%G, 10%B is about right for a standard mode
> change.  If it isn't that, it is close.  
> 
> Sometimes a single channel provides the best conversion, or at least
> comes close to the desired result.  It may be the red, green or blue
> channel, but usually it is some combination of at least two channels.
>  Since Hue and Saturation are no longer relevant in B&W, it's a matter
> of selecting and blending those channels that give you the tonality
> distribution and separation you want between tones.  And since we
> don't see in B&W, we get to select the relationships we want.  Adobe
> decided 3/6/1 was a good "general" formula for the "average" mode
> conversion, but one size definitely does not fit all.  
> 
> Regards, Lou
> 
> 
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "outdoornm"
> <outdoornm@> wrote:
> >
> > John,
> > 
> > If that is true, why don't you see those values in the channel mixer
> of a directly grayscaled 
> > image?  If you directly grayscale an image Image>Mode>Grayscale, you
> can no longer 
> > access the image via the channel mixer. However, If you change the
> profile of that same 
> > image to RGB and go back in thru'  Image>Adjustments>Channel Mixer
> you will see that 
> > the default is 100% red.  ????? Why doesn't it read   R30% G60% B10%
> since those are 
> > supposed to be the values in each channel?
> > 
> > Lincoln
> > 
> > 
> > --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "John Vitollo"
> <jvlist@> wrote:
> > >
> > > --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Eric
> Neilsen" <e.neilsen2@> 
> > > wrote: 
> > > > I asked Julianne Kost of Adobe that very question a few years
> ago and can't
> > > > find her response. I'm pretty sure it was either 70G/20R/10B or
> > > > 60G/30R/10B...but with my memory who knows. Guess you could
> manually do
> > > > those and see which more closely matches the RGB>Grayscale
> conversion.
> > > 
> > > Photoshop's default grayscale conversion is: R-30%  G-60%  B-10%
> > >
> >
>