Re: [APML] LRGB - film only

[Jerry Lodriguss <jerry@astropix.com>]

Hi Keith,

I don't think you need two techpan images for the L, you should be able to 
just use one. But you might need to go a little longer than 1 hour at f/7, 
depending on the object and how faint you want to go.

For the color though, you should expose each one to the skyfog limit for 
however many you want to stack for the color data. one hour at f/7 sounds 
ok, maybe you could go a little longer.

Also, unless you are shooting something with a really bright component, you 
won't get a whole lot in 20 minutes at f/7 with the Techpan.

You should be able to blend the color from the RG200 with the L from the 
Techpan and get excellent results, better than just the color alone. The 
only drawback is that the color will need just about the same exposure as 
the Techpan.

You probably could easily get away with a single color exposure also for 
the color data.

Jerry



At 08:01 PM 10/7/2003 +0000, you wrote:
>Hello,
>
>Having done ccd color work and seeing LRGB using ccd (L) and film (rgb), I 
>have laid out a project for some color imaging with a 140mm APO on 35mm 
>film and have decided to go LRGB by shooting Hypered TP followed by 
>hypered RG200.
>
>Following my experience with CCD work, normally I would shoot L at high 
>resolution for 2 to 5x the RGB (RGB is just for color, L is for details) 
>shot at lower resolution.  However, I am wondering if due to the 
>sensitivity of film vs ccd if this relationship is applicable.  Currently 
>I am planning to shoot 2 TP @ f/7 for 1 hr each, 1 TP @ f/7 for 20', 2 
>RG200 @ 1 hr each.  Ok, so that is almost 5 hrs per image.
>
>Has anyone done this kind of lrgb?  Is it necessary to shoot so long on 
>rgb or should that be reduced by ?half? just to colorize the TP 
>image?   Would the RG200 image degrade (due to color layers) the TP image 
>to the point that I may as well just shoot color only?  I really think 
>that the RG200 will give less definition than the TP image and it may not 
>be 'blendable' without serious impacts to the TP images.
>
>Any views appreciated.
>
>Keith
>
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