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better way of seeing noise before image is printed?



 
 
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  #1  
Old March 4th 07, 09:43 PM posted to sci.astro.amateur
Jason Albertson
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Posts: 2
Default better way of seeing noise before image is printed?

I like to print photos of images I've taken during planetary imaging
sessions. I have been printing images for several years, but I always have
the same problem: I can't seem to see the noise very well until after an
image is printed. Many, many times I have wasted initial prints because
noise rears its ugly head in the image. Then I have to go back and try to
gaussian blur the image at the risk of loosing sharpness when the image is
reprinted. My question is this: is there any easy way to see noise in
images before they are printed? If I zoom in 200% or better and readjust
brightness/ contrast, this helps somewhat, but I am usually still
disappointed once the image is printed. There must be a better way of
seeing/ predicting noise that will show up in photos. Any help would be
greatly appreciated.

Thanks in advance,
Jason


  #2  
Old March 4th 07, 09:52 PM posted to sci.astro.amateur
[email protected]
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Posts: 61
Default better way of seeing noise before image is printed?

On Mar 4, 3:43�pm, "Jason Albertson" wrote:
I like to print photos of images I've taken during planetary imaging
sessions. *I have been printing images for several years, but I always have
the same problem: *I can't seem to see the noise very well until after an
image is printed. *Many, many times I have wasted initial prints because
noise rears its ugly head in the image. *Then I have to go back and try to
gaussian blur the image at the risk of loosing sharpness when the image is
reprinted. *My question is this: *is there any easy way to see noise in
images before they are printed? *If I zoom in 200% or better and readjust
brightness/ contrast, this helps somewhat, but I am usually still
disappointed once the image is printed. *There must be a better way of
seeing/ predicting noise that will show up in photos. *Any help would be
greatly appreciated.

Thanks in advance,
Jason

Some of the soft ware routines, (i.e. Max DL or AIP4WIN?) alow you
to measure the statistics in a specific and controlled region of the
image. Pick a region of the dark sky and measure the std. dev. Hope
this helps.



  #3  
Old March 4th 07, 10:19 PM posted to sci.astro.amateur
Starlord
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Posts: 1,908
Default better way of seeing noise before image is printed?

Use Film.


--
There are those who believe that life here, began out there, far across the
universe, with tribes of humans, who may have been the forefathers of the
Egyptians, or the Toltecs, or the Mayans. Some believe that they may yet be
brothers of man, who even now fight to survive, somewhere beyond the
heavens.


The Lone Sidewalk Astronomer of Rosamond
Telescope Buyers FAQ
http://home.inreach.com/starlord
Sidewalk Astronomy
www.sidewalkastronomy.info
The Church of Eternity
http://home.inreach.com/starlord/church/Eternity.html


"Jason Albertson" wrote in message
ink.net...
I like to print photos of images I've taken during planetary imaging
sessions. I have been printing images for several years, but I always
have
the same problem: I can't seem to see the noise very well until after an
image is printed. Many, many times I have wasted initial prints because
noise rears its ugly head in the image. Then I have to go back and try to
gaussian blur the image at the risk of loosing sharpness when the image is
reprinted. My question is this: is there any easy way to see noise in
images before they are printed? If I zoom in 200% or better and readjust
brightness/ contrast, this helps somewhat, but I am usually still
disappointed once the image is printed. There must be a better way of
seeing/ predicting noise that will show up in photos. Any help would be
greatly appreciated.

Thanks in advance,
Jason




  #4  
Old March 4th 07, 11:14 PM posted to sci.astro.amateur
RMOLLISE
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Posts: 824
Default better way of seeing noise before image is printed?

On Mar 4, 3:19 pm, "Starlord" wrote:
Use Film.

--


Film?!

For the planets?!

Uhh..."no thanks." ;-)

The lowliest Quickcam planetary shot is better than the best film
planetary shot.

WAY better.

Unk Rod

  #5  
Old March 5th 07, 12:14 AM posted to sci.astro.amateur
Jason Albertson
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Posts: 2
Default better way of seeing noise before image is printed?


wrote in message
ps.com...
Some of the soft ware routines, (i.e. Max DL or AIP4WIN?) alow you
to measure the statistics in a specific and controlled region of the
image. Pick a region of the dark sky and measure the std. dev. Hope
this helps.


Can Photoshop show noise statistics? I can see how a certain level of noise
in the form of a number could be beneficial for printing purposes.

Jason


  #6  
Old March 5th 07, 12:34 AM posted to sci.astro.amateur
Starlord
external usenet poster
 
Posts: 1,908
Default better way of seeing noise before image is printed?

I have seen planetary photos done with film that would blow away most ccd
ones.
remember, one pic with film has over 3 megs of data in it.


--
There are those who believe that life here, began out there, far across the
universe, with tribes of humans, who may have been the forefathers of the
Egyptians, or the Toltecs, or the Mayans. Some believe that they may yet be
brothers of man, who even now fight to survive, somewhere beyond the
heavens.


The Lone Sidewalk Astronomer of Rosamond
Telescope Buyers FAQ
http://home.inreach.com/starlord
Sidewalk Astronomy
www.sidewalkastronomy.info
The Church of Eternity
http://home.inreach.com/starlord/church/Eternity.html


"RMOLLISE" wrote in message
ps.com...
On Mar 4, 3:19 pm, "Starlord" wrote:
Use Film.

--


Film?!

For the planets?!

Uhh..."no thanks." ;-)

The lowliest Quickcam planetary shot is better than the best film
planetary shot.

WAY better.

Unk Rod



  #7  
Old March 5th 07, 12:41 AM posted to sci.astro.amateur
RMOLLISE
external usenet poster
 
Posts: 824
Default better way of seeing noise before image is printed?

On Mar 4, 5:34 pm, "Starlord" wrote:
I have seen planetary photos done with film that would blow away most ccd
ones.



I never have. Period.

Unk Rod

  #8  
Old March 5th 07, 12:50 AM posted to sci.astro.amateur
Chris L Peterson
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Posts: 10,007
Default better way of seeing noise before image is printed?

On Sun, 4 Mar 2007 15:34:56 -0800, "Starlord"
wrote:

I have seen planetary photos done with film that would blow away most ccd
ones.
remember, one pic with film has over 3 megs of data in it.


Then you've never seen any good digital images. They are so far beyond
film there's no comparison. Film itself is lower resolution, lower
dynamic range, lower sensitivity, and higher noise. Good planetary
imaging requires taking many (ideally, hundreds) of very short exposure
images (to reduce seeing), and summing them (to reduce noise). Film
isn't sensitive enough for the short exposures, and even if it were,
scanning and stacking that many images for noise control would be a
nightmare.

People with webcams are routinely producing planetary images these days
that are far superior to the best film shots ever made, by anybody.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
  #9  
Old March 5th 07, 01:41 AM posted to sci.astro.amateur
Chris L Peterson
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Posts: 10,007
Default better way of seeing noise before image is printed?

On Sun, 04 Mar 2007 20:43:54 GMT, "Jason Albertson"
wrote:

I like to print photos of images I've taken during planetary imaging
sessions. I have been printing images for several years, but I always have
the same problem: I can't seem to see the noise very well until after an
image is printed. Many, many times I have wasted initial prints because
noise rears its ugly head in the image. Then I have to go back and try to
gaussian blur the image at the risk of loosing sharpness when the image is
reprinted. My question is this: is there any easy way to see noise in
images before they are printed? If I zoom in 200% or better and readjust
brightness/ contrast, this helps somewhat, but I am usually still
disappointed once the image is printed. There must be a better way of
seeing/ predicting noise that will show up in photos. Any help would be
greatly appreciated.


I'm a bit suspicious of your display system. Any reasonable monitor has
more dynamic range than a print, and should show noise better. I usually
see subtle noise on the screen that doesn't show up in prints, not the
other way around. Of course, you should be working at 100% for all
critical processing (not 200%, at least not in Photoshop). Is your
monitor reasonably calibrated with a gradient scale, such that you
aren't losing range off one end or the other? In Photoshop, you should
be able to see the difference between a black and a 95% K region, and
you should also be able to tell the difference between a white and a 5%
K region. You should never have to adjust the brightness or contrast
away from what matches your output.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
  #10  
Old March 5th 07, 02:04 AM posted to sci.astro.amateur
[email protected]
external usenet poster
 
Posts: 61
Default better way of seeing noise before image is printed?

On Mar 4, 3:52�pm, wrote:
On Mar 4, 3:43?pm, "Jason Albertson" wrote: I like to print photos of images I've taken during planetary imaging
sessions. ?I have been printing images for several years, but I always have
the same problem: ?I can't seem to see the noise very well until after an
image is printed. ?Many, many times I have wasted initial prints because
noise rears its ugly head in the image. ?Then I have to go back and try to
gaussian blur the image at the risk of loosing sharpness when the image is
reprinted. ?My question is this: ?is there any easy way to see noise in
images before they are printed? ?If I zoom in 200% or better and readjust
brightness/ contrast, this helps somewhat, but I am usually still
disappointed once the image is printed. ?There must be a better way of
seeing/ predicting noise that will show up in photos. ?Any help would be
greatly appreciated.


Thanks in advance,
Jason


* * Some of the soft ware routines, (i.e. Max DL or AIP4WIN?) alow you
to measure the statistics in a specific and controlled region of the
image. *Pick a region of the dark sky and measure the std. dev. *Hope
this helps.


As a specific example consider AIP4WIN. Go to the Measure\pixel tool.
Choose a circle diameter of 60 pixels in the dark sky region. In one
case the mean is 3.77 with a sdt dev of 9.66. This operation is about
as fast as looking at the image.

 




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