RE: [APML] Beginner scanner images

["R. Scott Ireland" <ireland@gate.net>]

Using adjustment layers in Photoshop is a great tool.  You also have the
benefit of saving the file with the adjustment layers intact (Levels,
Curves, Hue/Saturation, etc.) so that you can pick up where you left off
later and keep tweaking (e.g. the edits you make are non-destructive to the
image until you flatten the layers).

The one downside is that Photoshop does not offer this functionality in 16
bit/channel mode.

If your scanner allows:

1. Scan at the highest bit depth.

2. Set your sky background (black point) and White point using Levels in
Photoshop.  This assumes that your histogram does not show data stretching
completely from one side to the other - if it does, try to scan leaving just
a little "breathing" room on both the shadow and highlight side. I prefer to
set prescans to leave just a little space on both sides to avoid any issue
of clipping.

3. Do some preliminary Curves adjustments for overall contrast and color
correction (still in high bit mode).

4. THEN convert to 8 bit/channel mode to use the power of adjustment layers,
layer masks, etc. for further processing.

By staying in high-bit mode as long as possible, you will help avoid the
proverbial "combed" histograms (evidencing gaps in the data) that result
from doing the initial processing in 8 bit mode.


Scott

R. Scott Ireland
ireland@gate.net
www.rsiphotos.com

> -----Original Message-----
> From: astro-photo-bounces@seds.org
> [mailto:astro-photo-bounces@seds.org]On Behalf Of Frank Barrett
> Sent: Friday, July 18, 2003 8:48 PM
> To: astro-photo@seds.org
> Subject: Re: [APML] Beginner scanner images
>
>
> Herm,
>
> Boy I read alot of hardened wisdom in your words here.  I particularly
> want to comment on your points 4 and 6.
>
> I think it was Matt BenDaniel that first taught me the utility of using
> layers in Photoshop.  If you don't like the way a layer has turned out you
> can delete it and start over.  And you're right, as long as you keep the
> master scan around you can always go back all the way to the beginning.
> And yeah, it's painful, but sometimes you just gotta admit to yourself
> that you screwed up and your image is a dog that can't be saved.  There
> were a few times when I almost quit...I just couldn't believe I spent all
> that time out in the cold drift aligning and meticulously working on focus
> and guiding not to reap any reward.  I've since learned to judge my work
> by a different ethic.  I only consider my time a waste if I haven't
> learned anything. Sometimes that's humbling, but I think it has helped me
> improve.
>
> And your comments about having fun are important.  I think I was putting
> too much pressure on myself in the beginning, like I had something to
> prove.  I made it more like work.  I felt obligated to go out every single
> clear night.  I worried too much about failure.  I woke up one night and
> asked myself why I was doing this if it wasn't fun anymore.  I began to
> view the hobby in a different light and it has made all the difference.
> I've realized that failure is part of the improvement process, and though
> I don't like to make (or admit) mistakes, accepting failure has allowed me
> to enjoy my time out under the stars to a very much greater extent.  I
> have a friend who once told me that if you take life too seriously and
> can't laugh at yourself then you will be most miserable indeed.  I was too
> young to understand his advice, but I think it's starting to sink in!
>
> Sorry for rambling, but your comments to Steve kinda struck a chord with
> me and I thought I would share...
>
> Have fun,  Frank
> http://celestialwonders.com
>
> > I think you are doing a fine job Steve.. a couple of things that I have
> > learned after many hours fooling around with a scanner.
> >
> > 1. its best to do raw scans with a scanner, import it into PS
> or PW and do
> > the final tweaking.. of course many scanners only will provide a
> > "semi-raw"
> > scan.. try to limit scanner fiddling as much as you can.
> >
> > 2. adjust the histogram by the numbers, as described in many web sites..
> > now you have a good scanned image, go at it with the program of your
> > choice.
> >
> > 3. vignetting is a pain, I was never really satisfied with any
> methods of
> > vignetting removal.. I think the best way is just to get an instrument
> > that
> > minimizes this.
> >
> > 4. no matter how much PS fiddling you have done, if it still looks weird
> > start over :) , soon you will learn to just give up on some images
> >
> > 5. after a while you will be able to do all your image
> processing in a few
> > minutes..
> >
> > 6. and finally, enjoy it.. the learning/experimenting process
> is a lot of
> > fun.
> >
> > steve banbury <banburys@sonic.net>  wrote:
> >
> >>HI Jeff--yes, I looked at the histogram before uploading the file, and
> >> could
> >>see it was clipped at the bottom end.
> >>The scanner has a plethora of histogram adjustments available--maybe too
> >> many
> >>for a beginner!
> >
> >
> > Herm
> > Astropics http://home.att.net/~hermperez
> >
> > _______________________________________________
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> >
>
>
> --
> Frank Barrett
> http://celestialwonders.com
> _______________________________________________
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>

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