hi all i have an problem always reading the histogram of an image
sometimes i dont at all, but now that i more focus in color adjustment
i wonder if someone can explain how to read it , i know when is clipping
to the right that means to much exposure, to left to much darkness
in the middle grey, know my question is sometimes i see other color also in the tones like blue, red and greens in the histogram what that mean if it is blue to much blue? example here(histogram has green ,yellow ,pink and red what that means




here another one when i set my levels to read histogram but the channels
red,blue, and green and i set it up so i see my chanels is colours how u read that here example

thanks in front
see were i circle an yellow border around histogram whit a lot of spikes what that mean?

Spikes, loss of information data.

I am by no means an expert on Histograms, but my understanding is that the colours just show how much of that colour is in the picture, for example Red over to the left means lots of Dark Reds, Blue mainly on the right lots of light blues.

You are right by saying that if the histogram is all bunched over to the left it is under exposed and to the right it is over exposed, but this may also be the case if you have a picture with a dark background and little light on the subject, the histogram will automatically bunch left because the picture is mainly built up with dark colours!

As for the spikes, these occur when you edit the picture in photoshop for example, when you open the picture in RAW it will have no spikes as soon as you make a curves adjustment or levels adjustment the spikes will show, as CHRIS says loss of information.

Like I said i'm no expert but alot of little bits of knowledge help build the bigger picture.

spikes can be a loss of information, but not necessarily. Gaps are a loss of
information.

From the bottom pic the spiked histogram does not represent the pic.
Not sure how the op managed to it.

Histogram is of huge importance to the way I work. Bit like Neo seeing through the Matrix.

thks guys

The histogram means alot to me...both as a photographer and as a retoucher

As a photographer:  I look at the histogram on my shoots...so that I dont have a lot of pixels hitting the left side.  The minute pixels hit the left side and start "climbing up the wall"...it means that that some number of pixels have lost all detail in the blacks... and I will never be able to see detail in that darkness again.  When I see pixels climbing the left wall as a photographer... it means...get out a fill light, or bring out a reflector, or change the ambient environmental lighting, so I get some new fill light in the shadows...to open them up...so I can see details in the dark area of my images again. 

When the pixels begin hitting the right hand side...those are the white pixels...then they become 255 in color...pure white!  If these pixels start climbing up the side of the wall...then it means that those pixels will be "Over Pure White" and will never be able to show me any more details in the whites.  If I purposefully want a blown out, clipped, over highlighted,  image or background...then maybe thats OK...because its my intention.  BUT, If I havent pushed the pixels to the right on creative purpose...then it means that I will have highlights or backgrounds that can NEVER recover any detail but pure flat white. YUCK! 

As a photographer, pixels climbing the right wall means I may have my F stop open`too much and must close down the lens.  I would rather close down the lens...keep detail in the whites...and then recover any detailed in the whites back in photoshop later...which I can do to absolute perfection!  SO...I try to hardly ever let my histogram get pixels climbing up either on the left or right walls.  As a quality photographer I know I want an image that has full range and tonality... and details in both the blacks and whites.  Having a histogram that falls short of the left and right walls is no problem for me...because I know I can make up for any deficiency I want in Photoshop when I get home.  By looking at the histogram as a photographer on location...I can be sure my images will not have closed up blacks... or burned out highlights in the final image...thats nice to know!

As a retoucher: When the histogram is hitting the left edge...then I know I may have dark areas in the image that may not have much detail...so I go to the middle gamma adjustment on the levels adjustment layer...and i pull it to the left...till I can see details in the blacks that were invisible before the adjustment...then I will selectively paint those in for the customer. I like the option of having visible detail in the blacks if I need it...if not...I can artificially create a dark mood in Photoshop on purpose.  Using the Levels Adjustment Layer is a great non-destructive way to recover details in the blacks without loosing detail and integrity in the image. 

If the histogram is to the right I know I may need to do a curves adjustment layer to bring down the overall white levels...because whites above 245 sometimes do not print well on paper...all you see is paper white...and no details.  I also know if the pixels on the right wall are occurring on the face ( Forehead, Nose or Cheeks) then I will have blown out white spots that need artificial skin and skin pores inserted.  These areas will be absolutely pure white...with no skin tone or detail visible or recoverable in them!  Because these areas are only pure white...I know I may have to clone in some skin color... and also some skin pore detail... from other areas in the image.  If there is not any skin texture in the fix...then just adding skin color alone will look too smooth and too artificial. The patch up job will look out of place.  You may need a skin pore library to add in some skin texture to make it look real again.  You need skin color, it needs to be matched in color to the surrounding skin by using a curve layer...and it will need underlying texture so it also matches the texture of the surrounding area too.  So when I see a histogram that has white climbing up the right wall...I immediately know I will have areas of white clipping that has no detail in it.  This may be OK...or it may mean I will have a tricky patch job ahead.

Sorry for all the detail...for me histograms tell me a lot of valuable information.

Cheers,

Ray

From the standpoint of retouching, the histogram is (for me) less useful than other tools. With curves, I can tell not only whether there are clipped highlights or blocked shadows, but I can also tell exactly where in the image they occur -- by holding the Alt key and clicking on the highlight and shadow sliders. And of course I can see the composite histogram in the curves dialog.

I have the histogram on a function key so I can pop it up when I want to see all three channels separately. But in practice, I rarely have any need to check it.

My sense is that you're relying too heavily on the histogram, but maybe that's just because of my particular habits and techniques.

I use Photoshop. You're using LR. That's another difference.

so from what i understanding  no image has an perfect histogram

Forget about histogram because your client will NEVER buy it from you.

thks all