Understanding 8-Bit vs 16-Bit Photos

8 bit vs 16 bit

You’ve probably heard about the difference between shooting RAW vs JPEG, right? But have you heard about the difference between an 8-bit image vs a 16-bit one?

These two things are highly related, yet many photographers don’t care about going deep into the math.

And that’s OK – I too chose to study arts in part to get away from numbers. Yet, they can be useful in photography.

Expressed very simply, a 16-bit image will let you do more extreme editing before losing quality and details. But that doesn’t mean it’s always the best option.

Now that I’ve hopefully piqued your interest, let me give you a deeper explanation so that you understand more about 8-bit vs 16-bit images, including the pros and cons of each and when to use them.

What is Bit Depth?

 

Digital information is stored as either 1s or 0s. Each one of those is called a bit. Now, a one-bit image can only be black and white because 1 bit can only be black if it’s a 1 or white if it’s a 0.

There aren’t any tonal values in between and there are no other colors. When you add more information to it, the color depth grows exponentially.

So, an 8-bit image doesn’t have 8 colors. Instead, it can hold 256 tonal values in three different channels (red, green, and blue). That equals 16.7 million colors.

A 16-bit image has 65,536 tonal values in the same three channels. That means 281 trillion colors.

A 32-bit image has 4294967296 tonal values, and let me tell you, I don’t even know how to read that. If you then multiply it by three channels… well, you get the idea.

So, what does that mean to you in real life photography?

graph showing the tonal range comparison of 8 bit image and 16 bit images

When you’re photographing, you can choose between shooting in JPEG, which generates 8-bit images, or RAW, which will give you images from 12 to 14 bits depending on the camera that you’re using.

So, that’s the first thing that’s influenced by bit depth. Then, you have to consider how you want to edit your images.

In Photoshop, you can choose to work in 8-bit, 16-bit, or 32-bit and this will determine how extreme you can make your edits before you lose quality or get artifacts like banding.

Let’s see what the difference is and when you should use each one.

What’s the Difference Between 8-Bit, 16-Bit and 32-Bit?

Difference between 8 bit color, 16 bit images and 32 bit depths in an image file format.

Bits Channel Representation

As I mentioned before, JPEG photos are 8-bit images. When you open them in Photoshop or any other editing software, they’ll stay in 8-bit mode.

Even if you change the workspace to 16 or 32-bit mode, there won’t be any extra information to work with.

This is OK in many cases as the human eye can’t actually see all the 16.7 million colors these types of images have.

The problem is in the editing process. If you need to make changes – for example, correcting a very under (or over) exposed image – then you’ll start to lose quality.

One of the most noticeable issues you encounter in this situation is the color banding that appears in grading areas that should look smooth.

On the plus side, you’ll have all the tools from Photoshop available, and the file size will be within a normal range.

16-bit mode is where you’d want to edit your RAW images. The images taken in RAW mode are 12 or 14 bits (this will depend on the camera). You can look for this information in your manual or by doing a simple Google search.

If you open them as 8-bit, you’ll be losing a lot of the potential because the extra information they collected is now compressed.

When you open them in 16-bit mode, then you’ll have enough ‘room’ to work with all the colors, tones, details and quality that comes in your RAW image.

This means that your files will be bigger, and unfortunately, some Photoshop tools aren’t available in this mode.

Still, if you can choose between 8-bit vs 16-bit depth, always choose 16 bits.

Finally, a 32-bit mode is available in Photoshop but your file will still be a 12 or 14-bit image.

So, this mode is very limited in its use and will put your computer to the test. That said, for some specific cases, it really is worth it.

If you’re doing an HDR image, it’s better to work with 32-bit color. This is because you have the information from three (or more) 14-bit images.

So the amount of detail that you can recover from the highlights and the shadows is amazing. Some special effects and extreme editing is also better in 32-bit color.

Is 16-Bit or 32-Bit Color Better?

For an image in Photoshop you can set 8 bit colors per channel, or a 16 bit image mode as the color space.

The logical answer to this question would be that 32-bit color is better because it has more information and therefore more detail and quality.

However, the practical answer is that 16-bit color is better to work with, except for a few specific situations.

In most cases it’s better to work with 16-bit color because you’ll have more options available in Photoshop, your computer will be faster, and the files will be smaller.

If you have to make some extreme editing to your photo, you can do it in 32-bit and then return to 16-bit to continue with the rest of the postprocessing.

In fact, once you’re done editing, you can convert it all the way to an 8-bit image for printing and, of course, for online sharing.

Ana Mireles is a Mexican researcher that specializes in photography and communications for the arts and culture sector.

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