4 Replies Latest reply on Oct 19, 2010 1:44 AM by Yammer

    Basic Histogram question

    StanWelks Level 1

      Do you read the histogram in ACR the same way you read the histogram for Levels in Photoshop?

       

      Thanks.

        • 1. Re: Basic Histogram question
          MadManChan2000 Adobe Employee

          Similar. Shadow information is on the left; highlight information is on the right. The exact appearance of the histogram in ACR will depend on your chosen output color space (e.g., sRGB, Adobe RGB, ProPhoto RGB).

          1 person found this helpful
          • 2. Re: Basic Histogram question
            StanWelks Level 1

            1. are the shadows always on the left for every image and the highlights on the right?

             

            2. Other than that, the colors in the histogram show you the concentrations of colors in any given part of the image. How do you use this?

            I see that the histogram changes as I make adjustments, though I am looking at the actual image to make adjustments, not the histogram. Is there a way to make changes based on just looking at the histogram?

             

            Thanks.

            • 3. Re: Basic Histogram question
              Yammer Level 4

              The histogram you see is a representation of the converted image using the current settings and selected colour space. So, if you choose a bigger colour space, you will often get more headroom in the histogram.

               

              The dynamic range of the raw data can be wider than the histogram too - don't forget the histogram represents your converted image - so manipulation of the basic sliders (like exposure) will show you how well it fits into the target space.

              • 4. Re: Basic Histogram question
                Yammer Level 4

                StanWelks wrote:

                 

                1. are the shadows always on the left for every image and the highlights on the right?

                 

                2. Other than that, the colors in the histogram show you the concentrations of colors in any given part of the image. How do you use this?

                I see that the histogram changes as I make adjustments, though I am looking at the actual image to make adjustments, not the histogram. Is there a way to make changes based on just looking at the histogram?

                 

                Thanks.

                Yes, the shadows are on the left, and the highlights on the right. I think you'll find this is almost universal in photo software. If you press U and O you will turn on under- and over-exposure warnings, these indicators are positioned over their respective ends of the histogram.

                 

                Being able to see separate colours in the histogram has some uses, like seeing which colours are responsible for blown highlights or shadow casts, and sometimes checking balance between R G and B in neutral peaks.

                 

                You should adjust your image visually on a calibrated/profiled monitor, and not worry too much about your histogram. It's there to assist rather than dictate.