Re: [APML] Chemicals for prints

[Brian larmay <power_windows4789@yahoo.com>]

Thanks Kent once again..
Wow..another huge aspect of photography..well...film
photography that is.

Ok..one last question which is more astro related..

How does one stack negatives together to reduce the
snr of any given astro shot for under the enlarger?

I remember a few years back on jerry's site he had
actually placed a positive on another positive of the
same subject.

Was that how you guys did this back then?

Alignment of the pos's and field rotation must have
been a killer if thats the case not to mention
airplanes in the frame.

Do you need a brighter bulb to compensate for density,
or just longer exposure time?
Im not saying I am going to go that far with this..i
dont like that much self torture but if I had to I
would!

This is of course before scanners and tools such as
photoshop came out.
Im sure you all appreciate them very much<g>.

Again, thanks for the info
Brian




> Brian:
> If you already have powdered fixer, no problem.
> Concentrated liquid chemicals 
> are just a little easier to use. Regular dilution.
> 
> The choice of developer and paper will determine the
> 'visual feel' of the 
> final print.
> For astrophotography, I prefer the final print to be
> neutral toned, but that 
> is just a personal preference. Paper manufacturers
> like Ilford and Kodak, etc. 
> have sample booklets that show what their different
> papers will look like. 
> You will also discover there are 'graded' papers and
> variable contrast papers. 
> One usually matches your negative contrast to a
> print contrast. To do this 
> graded papers carry contrast ratings like 1, 2, 3,
> 4, 5. "1" is low contrast for 
> contrasty negatives and "5" is high contrast for low
> contrast negatives. 
> Variable contrast papers use similiarly graded
> filters to achieve the contrast 
> change. If an astro negative is very weak or 'flat'
> a higher contrast like 4 or 5 
> will help it. A well exposed and processed astro
> negative should print well on 
> a 2 or 3. Just remember that a good print will have
> a clean white tone and 
> black tone somewhere in the image.     
> 
> There is no real standard.
> 
> Kent Kirkley
> > _______________________________________________
> Astro-Photo mailing list
> Astro-Photo@seds.org
> http://seds.org/mailman/listinfo/astro-photo
> 


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