Is the histogram optional?
Good day, hey hey, happy #TravelTuesday one and all! Today this post goes live as I sit at 35,000 ft high, at a steady cruise of around 560 MPH, heading from London to Orlando in preparation for Photoshop World! It’s the creative event of the year and everyone who’s anyone will be there. You’ll see more on that elsewhere though so, for now, let’s hit a subject we can maybe learn a little something from, which today is the basics of a histogram.
So, my intention here is to explain what exactly a histogram is showing you and how to make use of it to improve your photography both in-camera and in post. It’s no masterclass, but I reckon it’ll be useful.
Why have I chosen to write about such an exciting subject? Well, it has come to my attention that there are a lot of people out there who just ignore the histogram. Sometimes it’s ignored out of ignorance and sometimes out of a lack of understanding, but its very prevalence should be sending a message that perhaps it’s quite an important tool.
A histogram is telling you all about the quantity of light in your shot, and here’s how: –
The x-axis of the histogram is showing the frequency—on the left, the darker areas and on the right, the lighter areas. The y-axis shows the quantity of these frequencies. If there are more shadows, there will be more spikes on the left. If there are more highlights, there will be more spikes on the right.
Here are the key points: –
– If you have a single floor-to-ceiling bar at the left, your shadows are clipped. Similarly, if you have one on the right, it’s your highlights that are clipped. This is causing a loss of detail in each of those respective areas.
– If your histogram is split into channels of red, green, and blue, you’ll be shown gray to indicate that all three channels are overlapping. If it’s two channels, you’ll get a different colour: yellow, cyan, or magenta. This helps to show us which channels are behaving in which way.
– A correctly exposed image gives us a histogram which is a central peak, whereas something underexposed peaks on the left and something overexposed peaks to the right.
– A histogram can help us understand the overall exposure state of an image. A histogram is, however, scientific. Science and creativity sometimes work together, but not always. This considered, remember that as well as reading a “good” or a “bad” histogram to determine correct exposure, it’s still good practice to use the histogram as a tool to help rather than as the ultimate decider.
So, what lesson is there to take from this today? Well, perhaps make it a habit to keep an eye on the histogram both in camera and in post. Learn the basics and once you have, there’s nothing wrong with staying right there. Having that base knowledge to help keep details in images and expose correctly can be a lifesaver, and although learning all the fine details of a histogram may or may not make you more of a pro, it’s certainly a good foundation in either case to grasp the fundamentals. The histogram is not optional. ;)
So for now, until next week….