RE: [APML] Stacking the right negatives

[Alan Voetsch <critter12952@yahoo.com>]

Hi Chris,

--- Chris Schur <cschur@cybertrails.com> wrote:
> Two negs are shot one right after
> eachother.  Both are at sky
> fog limit, in my case 8 minutes.

Easy for you, it takes hours to reach sky fog at my
location and f/10. 8 minutes, wow. I don't always have
the luxury of back to back shots either. In this case
they will have been taken 2 weeks apart.

>  The negs are
> scanned at maximum
> resolution, and adjusted for 16 bit and a very low
> contrast. 

Raw scan? I'm using a SS4000.

> In photoshop,
> the images are cropped, cleaned up but not adjusted
> for brightness.

Good, I was planning to go straight to PWPro. What do
you mean by "cleaned up"?

>  I then
> take them into PWpro for registration. Back in
> photoshop they are summed in
> the following way:  Images are converted to
> negatives, then combined in
> layers with "multiply".  Then the resulting denser
> neg is made back into a
> positive and ajusted to make the final image.

OK guys, get ready, I'm going to have some questions
about 'layers'. :-) 

> "multiplying" negatives is the same as stacking them
> on a light table.  Of
> course you can also average them if the object is
> brigh enough.

Thanks Chris, this is chock full of information.
Probably more than enough to confuse and baffle me. 
:-)

Alan

__________________________________________________
Do you Yahoo!?
Yahoo! Mail Plus - Powerful. Affordable. Sign up now.
http://mailplus.yahoo.com

--  APML Archives at <http://astro.umsystem.edu/apml/>  ---
             Unsubscribe at <majordomo@seds.org>