Where is histogram in photoshop cs5

That's because most digital cameras these days are capable of taking photos that are 10 to 20 megapixels millions of pixels or more in size. To fit them all into the histogram, you would need multiple screens to view it! So instead, the histogram simply gives us an overall, birds eye view of how the tonal range of the image is being distributed across the highlights, midtones and shadows, and if any areas are being clipped to pure black or white.

Generally speaking, a well-exposed image will display a histogram showing a full, continuous range of brightness levels from black to white, and we see an example of that with this image. The left side of my histogram begins right up against that left "wall" of the histogram box, directly over pure black in the gradient below it. This means that some of the pixels in the image are already black the darkest they can possibly be.

I'll zoom in closer so we can get a better view:. Over on the other side of the histogram, we see that it extends pretty much as far to the right as it can go, with a tiny sliver of it appearing directly over pure white in the gradient below it. This tells us that some of the pixels in the image are already white the lightest they can be. So, already we know that our black and white points are looking good:.

What does the rest of the histogram tell us? Well, typically, we read a histogram from left to right darkest to lightest. If we start on the left and begin moving towards the right, we see that the histogram immediately begins to rise over the dark shadow tones, but then drops off as we get closer to the midtones in the center.

It then rises again and reaches its peak over the lighter highlight tones before rapidly dropping off as we get close to white:. Since the highest part of the histogram is over the lighter tones the highlights , this tells us that most of the pixels in the image fall within that lighter tone range. We have a lesser but still considerable amount of very dark tones in the image, indicated by the rise in the histogram over the shadows.

And finally, the slope over the midtones in the center tells us that while we do have detail in that midtone range, there isn't as much of it as there is in both the highlights and shadows. Let's look at the photo again, where we see that sure enough, most of it is made up of those lighter tones the woman's skin, the whites of her eyes, her sweater, and much of the background.

We also have a considerable amount of very dark tones her hair, eyebrows, eyes, and a smaller section of the background. There really isn't much in the way of midtones, at least not when compared with the amount of highlight and shadow detail, and this is typical of a high contrast black and white image.

So, the histogram did a great job of showing us the tonal range of this photo:. Let's look at a second image, this time a full color photo bride and groom photo from Fotolia :.

I'll once again open the Levels dialog box so we can view the image histogram. Either way works; the keyboard shortcut is just faster:. Let's zoom in closer and see what this histogram is telling us. Here again, we're seeing an example of an image that's well-exposed. The left side of the histogram starts at pure black and the right side ends at pure white, so we know that our tonal range extends to both extremes:.

Reading the histogram from left to right darkest to lightest , we see that it rises quickly over the shadow tones. But, unlike the previous image where the histogram dropped off in the midtones, this one stays relatively constant all the way up into the highlights where it takes a sudden, sharp turn upwards before dropping off at pure white:. What does this tell us? It tells us that we have plenty of image detail in all three areas shadows, midtones and highlights , but that we have more detail in the lighter tones than anywhere else.

Again, we can see this when looking at the image. The man's shirt and the woman's dress, both of which are white or close to it make up a large part of the photo, so that explains why the histogram is at its tallest over the highlights:. So far, we've looked at histograms for images that were properly exposed, but a histogram can just as easily reveal problems. For example, what if the histogram was showing a tall spike right up against that right wall of the histogram box:.

This is usually a sign that the image is overexposed. The tall spike pushed up against that right edge means we have lots of pixels in the image that are pure white, and that means we're most likely missing detail in the highlights. To show the effect is has on the image, here's a comparison of the man's shirt.

The image on the left is properly exposed, revealing lots of detail. The image on the right is overexposed with highlights clipped to pure white. Notice how much detail in the shirt is lost:. This usually means the image is underexposed with lots of pixels clipped to pure black, which means we've lost detail in the shadows.

Again to show the effect this has on the image, here's another comparison. In the well-exposed version on the left, we see lots of detail in the man's hair. In the version on the right which suffers from shadow clipping, much of the detail in his hair has been lost to pure black:. If you noticed these clipping problems when viewing the histogram on your camera's LCD screen right after taking the photos, you'd most likely adjust your exposure settings and re-shoot them.

In Photoshop, you may be able to correct these issues using Levels, Curves or Camera Raw, and we'll learn how to do that in other tutorials. For now, all we're concerned with is learning about the histogram itself. At this point, we know that the histogram displays the range of tones in the image from pure black to pure white. But how many tones are there, exactly, in a histogram? Is there a specific number of brightness levels that the histogram displays? Why yes, there is! A histogram displays exactly brightness levels , with one vertical black bar for each of those levels, although depending on the tonal range of your image, you may not actually see a black bar at every level.

If you get in close, though, and look along the top of a histogram, you'll notice that it's not smooth. Rather, it's made up of tiny little spikes and ridges, each one being the top of a thin vertical bar.

If you count them, assuming you have a continuous histogram from black to white and nothing better to do , you'll find exactly bars:. Why ? There's a couple of reasons for it. First, most of us need roughly brightness levels from black to white in order for our eyes to see what looks like a continuous tone image; that is, an image that flows seamlessly from one tone to the next without any visible gaps or breaks between them.

If we drop much below that, we start seeing banding and posterization, where jumps from one tone to the next become obvious. So that explains why the number is at least But why ? Why not , or , or ? That's because of how computers work. We need our images to contain at least brightness levels, but computers need to be able to process and store the images as bits and bytes. Long story short, the best way to meet both of these needs is to store images as 8-bit files a standard JPEG image is an example of an 8-bit file.

An 8-bit image file contains exactly possible brightness levels, which gives us the or so we need for continuous tone, plus a little extra left over for editing purposes. Still wondering where the the number comes from? If you think of 1 bit as being equal to 2, then 8 bits is 2 8 , or 2x2x2x2x2x2x2x2, which equals If you didn't quite follow that, don't worry. You can get all the benefits of histograms without knowing a thing about bits and bytes.

All we really need to know is that a histogram displays a range of possible brightness levels from black to white. In fact, we can actually see this if we look at the numbers below the left and right sides of the histogram in the Levels dialog box.

On the left side, we see the number 0 which represents pure black. On the right, we see the number which represents pure white. All Channels View. Displays individual histograms of the channels in addition to all the options of the Expanded View. The individual histograms do not include alpha channels, spot channels, or masks. In the All Channels View, choosing from the Channels menu affects only the topmost histogram in the panel.

If you switch to Compact View, the channel continues to be shown in color. If you switch to Compact View, the composite histogram continues to be shown in color. Std Dev Standard deviation. Displays the cumulative number of pixels at or below the level underneath the pointer. Shows the current image cache used to create the histogram.

When the cache level is higher than 1, the histogram is displayed faster. In this case, the histogram is derived from a representative sampling of pixels in the image based on the magnification. The original image is cache level 1. At each level above level 1, four adjacent pixels are averaged to arrive at a single pixel value.

When Photoshop makes a quick approximation, it can use one of the upper levels. Click the Uncached Refresh button to redraw the histogram using the actual image layer.

Entire Image. Selected Layer. Adjustment Composite. Displays a histogram of an adjustment layer selected in the Layers panel, including all the layers below the adjustment layer. When making adjustments using the Adjustments panel, changes are automatically reflected in the Histogram panel.

Original histogram B. Adjusted histogram C. Shadows D. Midtones E. When a histogram is read from a cache instead of the current state of the document, the Cached Data Warning icon appears in the Histogram panel. Histograms based on the image cache are displayed faster and are based on a representative sampling of pixels in the image. You can set the maximum cache level from 2 to 8 in the Performance preference. A higher cache level setting will increase the redraw speed for large, multi-layer files, but requires additional usage of system RAM.

If RAM is limited or you work mainly with smaller images, use lower cache level settings. Click the Cached Data Warning icon. Click the Uncached Refresh button. For information about cache level, see Histogram panel overview. You can use the Info panel to see the color value of pixels as you make color corrections. When you work with the Properties panel, the Info panel displays two sets of color values for the pixels under the pointer.

The value in the left column is the original color value. The value in the right column is the color value after the adjustment is made. You can view the color of a single location using the Eyedropper tool. You can also use up to four Color Samplers to display color information for one or more locations in the image. These samplers are saved in the image, so you can refer to them repeatedly as you work, even if you close and reopen the image.

You can view color information for specific pixels in the image while adjusting color in the Properties panel. Make adjustments in the Properties panel. As you make adjustments, view the before and after color values in the Info panel.

Move the pointer over the image to view color values at the pointer location. You still have access to the scroll controls and to the Hand and Zoom tools using keyboard shortcuts. To delete a color sampler, drag the sampler out of the document window. Legal Notices Online Privacy Policy. Buy now. View histograms and pixel values Search. Make it. About histograms.

Histogram panel overview. By default, the Histogram panel opens in Compact View with no controls or statistics, but you can adjust the view. Adjust the view of the Histogram panel. Choose a view from the Histogram panel menu. Displays a histogram with no controls or statistics. The histogram represents the entire image. View a specific channel in the histogram.

Choose an individual channel to display a histogram of the channel, including color channels, alpha channels, and spot channels. View channel histograms in color. From the Histogram panel, do one of the following:. View histogram statistics. Choose Show Statistics from the Histogram panel menu. Do one of the following:.

To view information about a specific pixel value, place the pointer in the histogram.