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Re: [OM] Composites from Brackets (was "Bracketing Shots, etc.")

Subject: Re: [OM] Composites from Brackets (was "Bracketing Shots, etc.")
From: Garth Wood <garth@xxxxxxxxxxxxxxx>
Date: Thu, 10 Dec 1998 09:40:22 -0700
At 05:25 PM 12/9/98 -0600, you wrote:

[snip]

>Any chance you have, or could provide, an example of your very interesting
>technique? I'm thinking perhaps of a raw scan of both slides and then the
>composite creation. Any further details about the computer work involved
>would be welcome too. 

Joel (and anyone else who's interested):

Sure, it's possible.  The few shots I've done this with are unfortunately 
sitting on a friend's computer halfway across Edmonton, and were done for 
commercial purposes, so I don't have the right to re-post them here.  However, 
I *do* have some shots that I took from my last trip to Jasper (tentatively 
entitled "Sunrise over the Colin Range") taken at around 7:00 A.M. in late 
September.  The Colin Range (a group of mountains, natch) were east of the 
vantage point I was at, and I shot brackets in one-stop increments with 
boundaries of +/-2 F-stops for each separate time, hoping to capture the 
foreground shadow detail sufficiently so that it wouldn't be completely black 
on one of the images.  The underexposure brought out a lot more detail in the 
dawn light in the cloud formations above the mountains.  Looking back, I should 
have bracketed even more -- I was using Fuji Velvia, and +/-2 F-stops wasn't 
enough.  But I could make it work.

My friend has a drum scanner (YOWZA!), so you can get max detail and crispness 
out of any slide.  In this case, I'd scan the outer group of the bracket (the 
+2 shot and the -2 shot), and then start creating clipping paths to separate 
the foreground from the background (essentially, separating everything else in 
the picture from the sky itself).  Finally, the sky path from the -2 shot would 
get combined and aligned with everything else from the +2 shot, and voila! -- 
you have a digital composite with lots more detail than any single original.

This is labour-intensive, even with the new breed of intelligent plugins for 
software packages like Photoshop, because doing clipping paths can be very 
finicky and time-consuming.  As well, you work at very high resolution, so 
there's lots of "canvas" to worry about.  However, if you're planning on later 
reducing the resolution considerably (as I'm planning to do when I put the shot 
up in the Gallery), you don't have to be so precise, 'cause the algorithms used 
to re-sample an image to make it smaller "hide" a lot of the edge errors and 
inconsistencies you may have introduced.

That's it in a nutshell.  I don't know precisely when I'll be able to do this 
particular manipulation (I've been thinking about it for months now), but when 
I do it, I'll certainly post the full details to the Gallery.  It won't be 
prior to the New Year, that's for sure!  8^>

Garth

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