Digital BW, The Print

Really excellent example.
With regards to the polariser, I do often use one.  But I was 
refering to going from the blue to the black, not how to get the 
blue in the first place.
Your Joshua tree rock is perfect, just what I am trying to achieve 
(I don't have any decent examples loaded up, but I have a bunch of 
similar stuff, dead trees, rocks etc from the Setti Valley in 
Morocco - also cobalt blue).  When I try to get it that dark, the 
posterisation that results is awful, really unacceptable.  I spent 
days playing with red filters, B&W vs colour modes (with custom 
WBs..) polarisers on and off trying to get the capture as good as 
possible and I've just not managed it.
I guess it is my digital file.  I need to be using 12bit capture and 
being extremely careful with how I process I guess.
I was just looking for tips from those that are evidently getting 
much better results and have more experience than me - you are on 
that list looking at the Joshua tree example.

Thanks for the help
Steve

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Editor P.O.V. 
Image Service" <editor@p...> wrote:
> Um...Sorry for asking this..
> 
> Why not simply shoot with a polarizer? It's really a lot 
simpler..  
> Sometimes, as others have already noted during other threads, one 
needs 
> to do more than simply accept whatever RGB data a digicam shovels 
out.. 
> Filters make as much sense in the digital age as they did pre-
PhotoShop 
> in many cases..  Sometimes the data you need just is available if 
you 
> leave all the filtering until post image capture.. You can't ask 
> software to polarize the sky for you.. How would it know which 
angle 
> from the vertical  light waves were at?  Not to mention, it can't 
> suddenly add detail that was obscured by other data - like 
removing the 
> reflection from a water surface so you can see below..
> 
> Assuming you are capturing digitally or from an RGB scan of a 
color 
> slide/neg, after starting with that cobalt blue sky,  use the 
channel 
> mixer to move the really dark blue sky you should now have to 
black..  
> or use Convert to B&W Pro or a Silver Oxide filter for whatever 
film 
> type you want and just select a red-filter for pre-filtering?
> 
> Heck, nothing prevents you from shooting through a red filter with 
a 
> polarizer onto  even a digital back or digicam - not to mention 
onto any 
> B&W film.. 
> 
> Then you'd have those black skies you want to start out with..
> 
> BTW: That boulder shot of Paul's,  looks to be from Joshua tree 
and shot 
> with a deep red filter (both the boulders and the sky seem to have 
that 
> look to them).  The skies there can be cobalt blue with not a hint 
of 
> clouds, so that deep blue sky is a great starting point.  And 
certainly 
> more likely than in the village scene you compared it to.  With 
clouds 
> in your sky, and given the likely climatology, that village scene 
had a 
> sky about as dark as one might expect..
> 
> 
> To illustrate what I'm talking about, and not just sound like I'm 
> throwing rocks.. Here's something that took me significantly less 
than 
> five minutes.
> 
> Here's the detail of a color slide I shot at Joshua Tree (using a 
> polarizer):
> http://www.p-o-v-image.com/images/joshtest/start.jpg
> 
> next converted by Convert to B&W Pro with no pre-filtering:
> http://www.p-o-v-image.com/images/joshtest/unfiltered.jpg
> 
> next converted by Convert to B&W Pro with Red pre-filtering:
> http://www.p-o-v-image.com/images/joshtest/prefiltered.jpg
> 
> a "final" version, with the levels tweaked a bit (I could have 
lightened 
> the boulders more in levels or used curves to really lighten them 
to 
> match Paul's image more):
> http://www.p-o-v-image.com/images/joshtest/final.jpg
> 
>  
> Keith Krebs
> 
> "Just some guy," caretaker of the Multiverse's largest EPSON 
printer 
> User Community (highly recommended by Vogon Poets and MegaDodo 
> Publications), at:
> http://groups.yahoo.com/group/EPSON_Printers/
> and  the Multiverse's largest Canon printer User  Community at:
> http://groups.yahoo.com/group/Canon-printers
> "For the rest of you out there, the secret is to bang the rocks 
together 
> guys"