House of Hacks

Saturday, November 26, 2016

How to use histograms in Photoshop


Description

Histograms can be found in Photoshop for use in post-processing, not only on the back of our cameras when making the exposure. In this final episode of the Histogram series, Harley shows the different places histograms show up and what they represent within the image.

Other Histogram videos

Other Photography videos

For a written transcript, go to How to use histograms in Photoshop

Music under Creative Commons License By Attribution 3.0.
Intro/Exit: "Hot Swing"
by Kevin MacLeod at Incompetech

Sound effect: living-room-light-switch by alienxxx at FreeSound

Transcript

Histograms are an important tool when making an image in-camera. They also have their use during post-processing. In this episode of House of Hacks, I talk about how they work in Adobe’s Photoshop.

Hi Makers, Builders and Photographers. Harley here.

This is one in a series of videos about understanding and using the histogram. The others can be found in this playlist. I also have a playlist of other topics related to photography.

Today, we'll look at histograms in Photoshop. In this application, histograms tell us the same information as they do on the back of the camera but instead of just one histogram, Photoshop has several because of the different ways to view the image.

First off, if the histogram isn't visible, go to the Windows menu and select Histogram or you can click this icon.

By default it shows a little view like this. Click on this option drop down and select "All channels view" to see multiple histograms, one for each channel.

In many images all the channels will be very similar. But in some instances they might be quite different.

The split channels can be useful in situations where one color is predominant in your image. They help you see how adjustments to the image impact each color to help you know when one channel might start clipping, losing detail in the final image.

There's also this combo box that controls what is displayed in the top histogram. Personally, I like to show luminosity.

These histograms show the information for the image with all the adjustment layers applied. It’s the final histogram for the processed image.

As you turn adjustments on and off, you can see the histograms change accordingly.

Histograms also show up in some adjustment layers such as levels and curves.

The histograms that show in adjustments are the histogram for the image as that layer sees it, taking into consideration the original image and any layers below the current layer. This means adjustment layers above and below the current layer may have different histograms than the current layer.

As an example, this levels adjustment layer has a histogram for the original image.

If we make some adjustments and then add a curves adjustment above it, the curves layer shows a histogram based on the changes made by the levels adjustments.

If we make some adjustments on the curves layer, we can see the main histogram shows the results.

Also, if we make adjustments in a particular color channel, we can see how those changes impact that channel in the global histogram view.

If our adjustments are too extreme, we can see in the channel’s histogram that we start to lose details in this particular channel without the typical clipping showing in the main histogram curve.

In conclusion, I’d love to hear in the comments below about your experiences with the histogram, particularly during post-processing.

If this is your first time here at House of Hacks: Welcome. I’m glad you’re here. We’d love to have you subscribe. Through this channel I hope to inspire, educate and inform makers in their creative endeavors. Usually this involves various physical media like wood, metal, electronics, photographs and other similar materials. Thanks for joining me on our creative journey. So subscribe and I’ll see you again in the next video.

Now, go make something. It doesn’t have to be perfect, just have fun!