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"Advanced" image processing

 
 
Alan Meyer
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      11-01-2006
My own feeling about editing images is that it's as much an
art form as photography or painting - just different. Or maybe
not so much different as combining the two. The only problem
comes in when someone pretends an edited image is not
edited.

But this topic has been argued to death in this newsgroup.

Here's some practical advice:

1. If you haven't got $600 to burn on Photoshop, there are
cheaper ones that will do what you want. The one I use
is the GIMP - a totally free, open source image editor
that does a great job.

See http://www.gimp.org

2. Simple image editing is often very easy. Sometimes
there's just one button to push to "auto-enhance" the color
of an image, or very simple controls in "curves" or "levels"
to correct contrast, haze, and other problems.

3. Sophisticated image editing is very hard. There is a
huge amount to learn and a lot of it requires hours upon
hours of trial and error learning to see what the effects
of the controls are. Experts may think nothing of putting
many hours into a single image.

Alan

 
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Scott W
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      11-01-2006
Alfred Molon wrote:
> Just curious if anybody knows techniques to substantially enhance images
> taken under bad lighting or weather conditions. For instance if you shot
> photos on an overcast, dark day, if there is a way to make these photos
> shine. Would it be possible to transform an overcast sky into a nice
> blue sky?
>
> Or if you shot images under hazy conditions, with poor visibility, would
> it be possible to give these images "vibrance", good contrast and
> colours and if so how?

There are a lot of things you can do to punch up a photo, but in doing
so you risk lossing the mood that it captured. The worst part is that
if you go too far you end up with photos that look like Ken Rockwell's.

http://www.kenrockwell.com/gallery.htm

To me a photo is good if it captures at best it can the mood at the
time, if this is grey and overcast so be it.

I have seen people paste a blue sky in a photo that was taken when it
was overcast, not a good look at all.

When I have done heavy editing of a photo to try really punch it up I
find that I might like it, for about 5 minutes but the more I look at
it the more it just seem to look very wrong.

Scott

 
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David J Taylor
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      11-01-2006
Alfred Molon wrote:
> Just curious if anybody knows techniques to substantially enhance
> images taken under bad lighting or weather conditions. For instance
> if you shot photos on an overcast, dark day, if there is a way to
> make these photos shine. Would it be possible to transform an
> overcast sky into a nice blue sky?
>
> Or if you shot images under hazy conditions, with poor visibility,
> would it be possible to give these images "vibrance", good contrast
> and colours and if so how?


Paint Shop Pro includes filters which aim to do some of this, by contrast
and saturation changes. Look at tools like "Clarify" and "One-step photo
fix".

But you can't turn clouds into clear blue sky (except by replacement), and
there's no way to create shadows from the existing image imformation
(except by guessing where they might be) to increase the dynamic of an
image.

David


 
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Alfred Molon
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      11-01-2006
In article <(E-Mail Removed)>, Charles
Schuler says...
>
> Wow, what a question. You can replace the whole sky with Photoshop! You
> can adjust the heck out of everything!


It's not that easy. If you simply replace an overcast sky with a blue
sky, it will be very obvious for everybody because the lighting in the
rest of the image will not match. Additional steps would be necessary
and I wonder which ones. I'm not even sure you can do that and get a
natural looking result. The other option would be to keep the overcast
sky and process the image to make it look better, but then what would
you do?
--

Alfred Molon
------------------------------
Olympus 50X0, 7070, 8080, E300, E330, E400 and E500 forum at
http://tech.groups.yahoo.com/group/MyOlympus/
Olympus E330 resource - http://myolympus.org/E330/
 
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Alfred Molon
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      11-01-2006
In article <(E-Mail Removed) m>, Scott W
says...

> There are a lot of things you can do to punch up a photo, but in doing
> so you risk lossing the mood that it captured. The worst part is that
> if you go too far you end up with photos that look like Ken Rockwell's.
>
> http://www.kenrockwell.com/gallery.htm


Ok, these are way oversaturated.

> To me a photo is good if it captures at best it can the mood at the
> time, if this is grey and overcast so be it.
>
> I have seen people paste a blue sky in a photo that was taken when it
> was overcast, not a good look at all.


I once saw a before-after image of an image restoration artist who
successfully managed to replace an overcast sky with a blue sky. The
photo still looked natural. I wonder how he did it.
--

Alfred Molon
------------------------------
Olympus 50X0, 7070, 8080, E300, E330, E400 and E500 forum at
http://tech.groups.yahoo.com/group/MyOlympus/
Olympus E330 resource - http://myolympus.org/E330/
 
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Alfred Molon
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      11-01-2006
In article <(E-Mail Removed)>, Ken Tough says...

> Why don't you put an example shot on a webpage somewhere, and
> challenge readers to do their best at improving the shot. It's
> a fun exercise.


Ok, here is the page with the samples:
http://www.ddde.de/enhance/

Both photos taken in Chongqing (China), one of the most heavily polluted
places on earth. Image 1 shows the Yangtze river and there is heavy
smog. To the left is the JPEG of the camera, to the right the best I
achieved with the RAW converter. You can also download the original RAW
file (compressed as RAR).

The second image has actually already been optimised with the RAW
converter, but you might still be able to improve it.

This is unfortunately the typical situation in the east of China, where
the skies are very often hazy and polluted.
--

Alfred Molon
------------------------------
Olympus 50X0, 7070, 8080, E300, E330, E400 and E500 forum at
http://tech.groups.yahoo.com/group/MyOlympus/
Olympus E330 resource - http://myolympus.org/E330/
 
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=?iso-8859-1?q?Martin_S=F8rensen?=
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Posts: n/a
 
      11-01-2006

Greg "_" skrev:

> Not really photography at that point, more like image
> molestation-bordering on rendering.
>

Yes, it is about impossible to draw the line, isn't it?

How far you can go depends on what you want to do - do you want to show
the facts as you saw them or just to use the picture as starting point?

In any case, you start even before you press the shutter - by selecting
what is and what is not in the picture. The camera or your computer
adjusts things - the RAW is useless on its own.

I have no problem with adjusting sharpness and colours, in in most
cases cropping is fine too (can be dubious if you cut "unwanted"
persons out).

At the moment I am preparing a picure for a present. It is of a
traditional Algarvian house to someone who likes the style of
architecture - i.e. a representation of a type of house more than a
specific house. I have no problem in removing power lines and TV
areals(sp?), for this purpose I think it is ok.

/Martin

 
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Barry Pearson
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      11-01-2006
On Oct 31, 11:26 pm, Alfred Molon <(E-Mail Removed)>
wrote:
> Just curious if anybody knows techniques to substantially enhance images
> taken under bad lighting or weather conditions. For instance if you shot
> photos on an overcast, dark day, if there is a way to make these photos
> shine. Would it be possible to transform an overcast sky into a nice
> blue sky?
>
> Or if you shot images under hazy conditions, with poor visibility, would
> it be possible to give these images "vibrance", good contrast and
> colours and if so how?


Are you asking for something beyond the sort of LAB processing done by
Dan Margulis in "Photoshop LAB Color -The Canyon Conumdrum and Other
Adventures in the Most Powerful Colorspace"? Figure 9.15 shows the use
of LAB to get through the haze in Hong Kong.

--
Barry Pearson
http://www.barry.pearson.name/photography/

 
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Alfred Molon
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      11-01-2006
In article <(E-Mail Removed) .com>,
Barry Pearson says...

> Are you asking for something beyond the sort of LAB processing done by
> Dan Margulis in "Photoshop LAB Color -The Canyon Conumdrum and Other
> Adventures in the Most Powerful Colorspace"? Figure 9.15 shows the use
> of LAB to get through the haze in Hong Kong.


Do you have a link? I've never tried this sort of processing.
--

Alfred Molon
------------------------------
Olympus 50X0, 7070, 8080, E300, E330, E400 and E500 forum at
http://tech.groups.yahoo.com/group/MyOlympus/
Olympus E330 resource - http://myolympus.org/E330/
 
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Paul Saunders
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Posts: n/a
 
      11-01-2006
Alfred Molon wrote:
> In article <(E-Mail Removed)>, Ken Tough says...
>
>> Why don't you put an example shot on a webpage somewhere, and
>> challenge readers to do their best at improving the shot. It's
>> a fun exercise.

>
> Ok, here is the page with the samples:
> http://www.ddde.de/enhance/
>
> Both photos taken in Chongqing (China), one of the most heavily
> polluted places on earth. Image 1 shows the Yangtze river and there
> is heavy smog. To the left is the JPEG of the camera, to the right
> the best I achieved with the RAW converter. You can also download the
> original RAW file (compressed as RAR).
>
> The second image has actually already been optimised with the RAW
> converter, but you might still be able to improve it.


How about this?
http://www.wilderness-wales.co.uk/mi..._processed.jpg

It was a rush job, just a couple of minutes in Photoshop. I could do much
better if I started with the RAW file and took more time over it, but this
is just to show what's possible in a couple of minutes. The banding in the
sky is due to working on the 8 bit jpeg, this wouldn't happen with the 16
bit RAW file.

I used;
Levels - to set the black and white points
Curves - to brighten the midtones.
Contrast masking - to even out the image (actually I overdid this)
Unsharp Mask with a huge radius (80 pixels) - to enhance the local contrast
Saturation - just a touch to put a bit of colour back (the previous step
tends to lose colour)

Nothing I could do about the sky though.

Much better results are possible though, if you're prepared to spend enough
time on it, but at least this clears the haze.

Paul
--
http://www.wilderness-wales.co.uk


 
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