Re: [APML] Blue response on astrophotos

[Chuck Vaughn <aa6g@aa6g.org>]

Nicola,

It depends on how you want to treat UV though since it's not in the 
visual spectrum. If you want to reproduce only the visual spectrum then 
color film is probably pretty close for reflection nebula. If you want 
to record as much as possible then you need to go beyond the visual 
spectrum. This will alter the color since you're recording an extended 
color space and displaying it with a visual color space.

Take an object like the Pleaides nebulosity. Most of it's light is in 
the near UV. It records very well on TP, not as well on color film, and 
is very difficult to see visually. It's likely that more than 50% of 
the total brightness of that reflection nebula is short of 400nm.

I'm not saying you should boost the blues because your film has limited 
response, but just pointing out the nature of the film and the object.

Chuck

-------------------------

>> much better than color film. With color film you only record perhaps
>> 50% of the light from a typical reflection nebula.
>
> 50%! Oh my gosh I didn't knwo about that...this is something I have to 
> remember
> when I process my photos, I should boost the blues before to balance 
> the
> overall picture. I'll see what I can do. I'll show you all my M8 / M20 
> wide
> field ASAP.
>
> Regards,
> Nicola

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