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photoshop cs2 levels control histogram touching RIGHT END

Hi
In photoshop cs2 when I look at histogram I many times see the right side bunched up   so I use EXPOShere  or brightness control ot lightness from hue/saturation  to darken the image and move the RIGHT side of the histogram more left
Now here is the question  if I use levels and play with the sliders I can accheive the same darkening of the image BUT THE HISTOGRAM is still bunched up towards th RIGHT end WILL THIS AFFECT PICTURE QUALITY?
Thanks
Orshulim
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orshulim
Asked:
orshulim
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2 Solutions
 
vanwrapsCommented:
The levels histogram in windows is a representation of the 256 tonal levels from dark on the left side to white on the right side.  The bunched up pixels on the right side are pixels in the image that are blown ie completely white.  Very few things in a photo should be completely white.  This indicates an improper exposure of the photo.  The only pixels in a properly exposed photo that should be pure white are specular highlights such as reflections off of crome on a bumper.  The histogram is actual one of the more simple adjustment tools for photoshop but like many of photoshops tools, not knowing exactly what is happening when you use it can trash a photo.  The black triangle at the bottom left when moved to the right will turn the darker pixels solid black.  The triangle on the bottom right of the histogram when moved to the left will turn the lighter pixels solid white.   This is essentially throwing away the detail in the photo even though it looks as though you are making it brighter with more contrast.  The middle slider will adjust all of the values toward white or black.  Be very careful when editing photos not to turn shadows to solid black or light details to solid white.    A 'good' histogram for a photo should typically have very few if any blown pixels and very few if any black pixels as these are not natural in photos.  Pure black pixels are represented by the tall spikes on the left side of the histogram whereas pure white is represented by the tall spikes on the right side of the histogram.  To avoid losing data in the photo try using only the middle slide to make the tonal adjustment.  The hue/saturation is really more for changing the color of an image and then saturating it with color or desaturating it to grey scale.  To get a feel for the levels histogram try taking an image  then  image/mode/greyscale   >move the left histogram marker to the middle and watch everything that is on the darker side of the image turn solid black.  >move the right histogram slider to the left and the lighter pixels will all turn to white.  You should basically have an image that is black and white with very few shades of grey in between.  If no data in the histogram is touching the right or left side then you will usually slide the slider(s) right up to the data but don't go past if or you will clip it like a rookie.  If you are serious about using photoshop for print I would suggest buying a book by Deke Mclelland or Bruce Fraser on photoshop.
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David BruggeCommented:
If you have images that have a lot of white, such as a lot of white background, or an image in the snow, or on the beach, then you should expect to see a a "bunching up" of the historgram around the right. I do a lot of catalog shots where we intentionally "blow out" all of the background. The histograms all have a very pronounced spike at the right.

Likewise, if you have a night scene, or an object surrounded by a black background, then you should expect to see a "bundhing up" of the historgram around the left.

Vanwraps is correct, it is preferred to use the Levels or Curves dialog to adjust the lightness/darkness of an image, but only because you have more control and can see a graphical map of your tonal values

Here is a very easy to understand tutorial on using histograms:
http://www.shortcourses.com/how/histograms/histograms.htm

David B.
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orshulimAuthor Commented:
Hi
Thanks to both of you.
My question concerns that I was editing thousands of shots that I cannot reshoot
and when I see the bunched up pixels on the right side I know I am overexposed but my question is which of the tools from photoshop is the correct one to use to bring back overexposed or under exposed images? Intresting enough after I finished adjusting the brightness if I use auto color or auto levels I am practiclly back where I started of.
Thanks
Orshulim

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David BruggeCommented:
There is a difference in an image that is over exposed and one that has the highlights blown out. In the over-exposed image, all of the tones are shifted to the right in the histogram. The darkest areas are light and muddy, and the overall image lakes contrast.

An image that has the highlights blown out can be other wise correctly exposed, that is to say the darks are dark and the midtones are where they should be, only the lightest areas of the image are solid white with no detail at all. The pixels read 0,0,0 meaning that there is no recoverable information in those areas.  There is little if anything that can be done to fix these images.

For over-exposed photos where these is still some detail in the light areas, you want to use the levels adjustment, but you don't want to move the highlight slider at all. If it were possible (and it's not) you would want to move it farther to the right.

What do want to do is bring the shadow slider up to the darkest area of your image. When you do this, the lightest areas stay where they are (preserving the detail), but all of the other tonal values shift down, effectively darkening the image without darkening the highlights.

Once this is done, you can adjust the midtone slider to adjust the apparent lightness or darkness of the image. Sometimes, a very light image can be salvaged by duplicating the entire image onto another layer and setting the layer mode to multiply. You can even do this several times for extreme cases.

Can you post a sample of the type of image that you are working with?  The fact that using auto levels brings the photo back to where it was before makes me suspect that you have blown out hightlights.

David B
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orshulimAuthor Commented:
Thanks
Where do I upload?
ortshulim
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David BruggeCommented:
Start by copying the URL of this question from the URL window at the top of your browser window.

Go to: http://www.ee-stuff.com/accessLogin.php?returnURL=%2FExpert%2FUpload%2Fupload.php
 and long in.

Paste the URL that you just copied into the window that says "Question:".

Then use the browse button to locate the file on your computer to upload;

You can ignore the comment section.

Click "Upload"

If the system is working (it wasn't when I tried it last night) you will be taken to another page and given a URL of your new uploaded image.

Copy that link URL and return here to your question.

Paste the link into a comment. Then, anyone visiting this question can click on your link and see your image.

David B

If the system is still not working, there are a number of free image hosting sites that you can use.

www.Photobucket.com is one of them, but you can do an internet search for others. You can open an account, upload an image and copy its URL. Then come back to this question and paste the URL in a comment that we can read.
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orshulimAuthor Commented:
Hi
I uploaded it with the id no. of this question
ID:22739081
thanks
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David BruggeCommented:
slight glitch here.

You were supposed to be given a URL to paste into the comment. Then any of us could have clicked on the URL and be taken to your file.

I have asked community support how to locate your file using the question number.

As soon as I have that link, I will post it and we will be back on track.

David B
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orshulimAuthor Commented:
Hi
i uploaded it correctly this time  with the full url from my page.
Thanks

Ps
How do I paste in a image from my files into a current open image in PS?
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orshulimAuthor Commented:
Hi
I want to take this opertunity to thank all of you for being so gracious in trying and helping.
Thanks
Orshulim
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David BruggeCommented:
There seems to have been a problem with your upload. After clicking the "upload" button, you should be taken to a new page that has a URL for you to copy and place in your question. This URL will let the rest of us see your file.

If you don't get taken to the new page, then your upload did not go through.

I went to this address:

http://www.ee-stuff.com/Expert/Upload/viewQuestionFiles.php

and entered 22739081

The only file that was in there was the test image that I uploaded just now to test.

Try uploading again, it seems to be working now.

David B.
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orshulimAuthor Commented:
Hi
sometthing is going on I tried to download the file it claims it is to small  it is  3.83m image .jpg  so itried and saved it smaller 2.12 the same thing happend then I renamed it to .zip same thing  

I will try now name it .txt
same thing I will make file small  and try again
finnaly after reducing file to size 7  from 12 in photoshop it uploaded name baby.jpg
Thanks
orshuim
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vanwrapsCommented:
Under the histogram is another slider that can be used to make the very light or white pixels have a little color.  Grab the one on the right and slide it to the left and you will see the light details and blown areas turn darker.  You can never get back detail that is not there but you can bring out very light details that might not appear normally on your output device ie; monitor, printer...
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vanwrapsCommented:
I think your question is well answered.  Do you have any points to give?  I need some.
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orshulimAuthor Commented:
Hi
I am cofused Are you talking about the OUTPUT level from LEVELS? that slider darkens the whole image.
Thanks
Orshulim
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David BruggeCommented:
A very cute child Orshulim!

I can see why you are so upset over losing the images. Unfortunately, there is no way to get the detail that was lost. As I mentioned before, the pixels measure 0,0,0 which is completely blank.

You can pull out the marginal detail by duplicating the layer and setting the blend mode to multiply. I did this on your photo, building up 7 or more layers (all set to multiply). I then merged these duplicate layers into a single layer and deleted all but the face.

The new layer was much too dark, which is what I wanted because I could then adjust the opacity back and forth to see if there was any improvement. (Not much, sad to say)

I then used the levels command to darken the midrange tones of the original layer.

Here is the revised photo: https://filedb.experts-exchange.com/incoming/ee-stuff/4276-baby-revised.jpg

I am very sorry that there is nothing more that I can tell you to do.

David B.
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orshulimAuthor Commented:
Hi
I am downloading it is very slow
I am confused  I do not understand the differeces between multiply darken and a host of other possibilities that darken the image.
Thanks
orshulim
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vanwrapsCommented:
This file appears to have been blown by a user and not the camera.  Do you have the original photo?
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vanwrapsCommented:
Yes the output levels.   Basically it means that your brightest white is set by the slider so if you move the output slider to the left it will change any white pixels to a darker color.  
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vanwrapsCommented:
thanks for the points orshulim
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