A Quick Guide to Tackling the Challenges of Color Banding
Color banding (lines of various colors) can be a creative touch if you paint a canvas. However, if you're a photographer about to hit save, it can be a nightmare.
We've put together everything you need to know - well, the most important things you need to know - about color banding in photography, including how to avoid it.
What is Color Banding?
Color banding is a common issue photographers face. It can show up as distortions that can appear as lines or circles of color in a sky or background of an image. It will only be visible in areas of a large swath of color rather than a section of colored details. Color banding is preventable and can usually be fixed, so don't panic. We're here to guide you.
What Causes Color Banding?
An image needs adequate bit depth to sustain various and sufficient shades of color for a smooth transition between colors. If there isn't enough tonal range to represent, from brightest to darkest, the different colors (your bit depth is too low), it can cause color distortions rather than a smooth gradation between color shades.
The number of bits gives you the tonal range. For example, an 8-bit photograph will have 256 tonal values per color, while a 16-bit one has 65,536. Sometimes fewer bits are enough, while you'll need more bits and tonal range at other times.
Keep in mind that today's technology (your digital camera and monitor) works with three color channels: red, green, and blue.
Multiply 256 tones per 3 colors, and you get 16.7 million colors. While that is sufficient for a detailed image area, it might not be adequate for a seamless area with too many variations of one color. To obtain a smooth transition in that area and avoid color banding, you need a larger tonal range.
This means shooting in uncompressed RAW, which holds far more information than shooting in JPG.
If an image has a good balance of tone values, you can adjust the curves or brightness to reach its maximum and create a greater range within the gradient. However, the quality of an image matters as well. If the resolution is too low or compression has caused tonal values to be diminished, you'll likely see some degree of color banding.
How to Test for Color Banding
You might not notice color banding until you hit save and print. However, you can check for it beforehand by doing a color banding test.
In Photoshop, open the Channel panel from the Windows menu.
It should pop up on the right side of your screen, and four channels will appear.
The first channel is RGB, which puts together the other three, allowing you to see the image in full color.
The three other channels form the picture, one for each color: red, green, and blue.
You can check for banding by activating each color individually by clicking on the eye icon next to each one.
If you're working with a JPG, you can sometimes see color bands appear while you're saving the file.
Try zooming into any area with a broad swath of one color, like the sky.
Save the file.
In the Preview option, begin lowering the quality of the file while watching to see if any banding shows up.
How to Avoid Color Banding
You don't have to wait for color banding to appear to deal with it. There are things you can do to avoid it while you're shooting and in post-processing. (Ideally, you should avoid doing anything during a shoot that could cause color banding. Avoidance is better than fixing later on.) Read on for some tips.
1. Photoshoots
Camera settings: Using the correct settings during a photoshoot can help keep your edits later subtle. Use the histogram to help guide you. (Remember that when it comes to color banding, over-editing can cause more problems rather than fixing them.)
RAW: As we said at the outset, the best way to avoid color bands is to shoot in uncompressed RAW. It holds the most information, offering enough color values to give the image a smooth transition.
Exposure: It is crucial to be as accurate as possible with exposure. Getting this right during the photo shoot will be more helpful than correcting it later to adjust for color banding.
Scene/background: Consider the scene's environment when you're positioning a subject or shooting without. For example, move your subject/model to where the sky is the most, even when shooting outdoors. This helps avoid the type of grading that could create banding problems.
2. Post-processing
There are some things you can do at the outset of post-processing to help you avoid color banding.
Bits: If at all possible, be sure to open your images in 16-bit.
RAW: Do most of your edits in uncompressed RAW to avoid loss of information.
Additional changes: If needed, make further changes that could cause loss of info, like reducing image size or saving it as a JPEG, do them after you're done making the significant edits in RAW.
How to Fix Color Banding
So, let's say you'd like to fix images you've already taken that show color banding.
8-bit files: To properly correct color banding, it should be done as a 16-bit file. If you have an 8-bit, you'll need to convert it into a 16-bit:
In Photoshop, open the Image menu.
Click on Mode, select 16 bit.
In the Fixing 16-bit file, you can choose options.
When you're done, retain the 16-bit option if possible or revert to 8-bit. The color banding should be gone.
16-bit files: If your image is 16-bit, you can proceed to make some adjustments or enhancements.
Blur: You can use the blurring tool to reduce or make banding less visible. However, we suggest you use the Smart Filter/Object. (This allows you to come back later to make any further adjustments.) To do this, follow these steps:
Duplicate your original Layer first by dragging it into the Create New Layer button. (You could also go to the menu Layer, then Duplicate Layer.)
Next, go to the Filters menu.
Select Convert for Smart Filters. Your duplicated Layer turns into a Smart Object, so you can work on it without changing the original.
Next, go to Blur in the Filters menu.
Select the Blur you want. This opens a pop-up window for Radius control.
Lastly, keep in mind that you are working on a second layer. This allows you to create a Layer Mask so that the Blur is only visible in the image area where banding is present.
Noise: Adding noise to an image is another way to address banding. You'll need to add a new layer from the Layer panel or the Layer menu.
Select Duplicate Layer and change the blending mode to Overlay. We suggest turning it into a Smart Object so you can come back to make later edits.
Add and adjust the noise. If you would like to make the noise layer even smoother, we suggest adding some Gaussian blur.
Lastly, add a Layer Mask if you want to save the subject from the Noise-Blur layer.
Texture: Another way to address color banding is to add texture. You can get a bit creative here by creating your own or using a download.
Start at the menu File.
Select Place, which takes you to a browser. Select a file from the browser. This adds the texture as a new Smart Object layer. You can make changes accordingly.
Conclusion
Don't be intimidated if you see color banding in an image - or you want to set your camera to avoid it. While the tips we have offered here may sound complicated, they're relatively straightforward.
Take your time and follow them closely. With some practice, you'll be able to tackle any color banding you find in an image. You might even get to the point where you can avoid color banding altogether.
The beauty of digital photography is the advanced technology behind it. It can work both for us and against us. The key is to learn the processes that allow us to manipulate that technology to create great images! And, yes, it is indeed possible - with some practice!
