8-Bit vs. 16-Bit | Bit Depth | What is Tonal Range?

Once you have watched the tutorial, I am sure you will be convinced. Then what should you do to properly make an 8-bit to 16-bit conversion? Well, thats easy. just go up to the pull down menu and select Image – Mode – 16-Bits/channel. Suddenly, you are whisked away to the wonders of color perfection. But, wait, you ask… what about that part, just below, that says 32-Bits/channel? Why talk about 16-bit when we can clearly select 32-bit and bask in all its glory? Well, settle down there, sparky. One thing at a time. I mean, if 16-bit is already trillions of colors, and can save the example in the video tutorial, isnt 32-bit just complete overkill? I sure think it is. But then again, who am I?

Once we have turned the 8-bit image into a 16-bit image, then we can make all of our Adjustment Layers and save our layered PSD or TIF file. When we want to send the file off to the prepress house, or magazine printer, simply go back to Image – Mode – 8-Bits/channel and save the flattened file for them. At this point, all the color changes are done, so no need to have all that extra data. It was only needed to avoid banding or other color corruption before the CMYK conversion.

So then, why do cameras still work in 8-bit bit depth? This is because 8-bit bit depth is old school, and the only one supported by JPGs. If a camera takes a picture, and saves as a jpg, it is good with 8-bit. It does not need to (or can not) make the extra jump to 16-bit. Don’t forget, we can only see a fraction of the 8-bit bit depth anyway. The issue comes in when we, the retouchers, start messing with things, and accidentally cause the banding. The camera did a good job, the first time around. Cameras that save in RAW format save that data with either 12-bit, or sometimes 14-bit.

 

What is 8-Bit Depth in Photoshop?

Each Color of an image in RGB (Red, Green, Blue) is created from a gradient from black to white. There are 256 shades of grey between Absolute Black and Absolute White. This means that Red has 256, Green has 256 and Blue has 256. The math is 256x256x256=16.7 Million Colors possible. However, it is actually possible to see the 256 shades (steps). If you can see them, it is refrerred to as banding.

The 8-Bit Depth is characterized by its limitation to 256 shades of grey in each color channel, potentially leading to visible banding in images, especially in areas with gradual color transitions. The term “8-bit” signifies the number of bits used to represent each channel, and this bit depth is suitable for many applications, including web graphics and standard photo editing.

While 8-bit allows for a vast range of colors, the potential for banding can be a concern, particularly in situations where smoother gradients are crucial. It’s essential to consider the nature of the image and the desired output when choosing between 8-bit and higher bit depths in Photoshop.

 

What is 16-Bit Depth in Photoshop?

In Photoshop, 16-Bit Depth refers to the color depth of an image in the RGB (Red, Green, Blue) color mode. Unlike 8-bit depth, which provides 256 shades for each color channel, 16-bit depth offers a significantly larger color palette. With 16 bits per channel, there are 65,536 possible shades for Red, Green, and Blue. The total number of colors becomes immense at 65,536 x 65,536 x 65,536, resulting in approximately 281 trillion colors.

The primary advantage of working in 16-bit depth is the substantial reduction of visible banding in images. Banding occurs when there aren’t enough steps between colors, leading to noticeable transitions between shades. With 16-bit depth, the increased number of possible shades allows for smoother gradients and more accurate representation of subtle color variations.

While 16-bit depth offers a vast color range, it may not be necessary for all types of images or projects. It is often preferred when working on high-quality and detailed images, such as those used in professional photography or graphic design, where preserving the integrity of color information is crucial. It provides a more significant color depth than 8-bit, resulting in improved tonal transitions and greater flexibility during editing.

 

Why use 16-Bit in Photoshop?

The short answer is to Avoid Banding.

The longer answer is that working in 16-bit depth in Photoshop offers substantial benefits, particularly in terms of color precision and image quality. With 65,536 possible tonal levels for each channel (Red, Green, and Blue), 16-bit depth provides a significantly larger color range compared to 8-bit. This extended depth helps eliminate banding issues, ensuring smoother color transitions and preserving more information during edits. It’s especially crucial for professional tasks like retouching, HDR imaging, and projects involving multiple adjustments where lossless editing is essential. Additionally, when preparing images for professional printing, the use of 16-bit depth contributes to color accuracy and high-quality output. However, it’s important to consider larger file sizes associated with 16-bit depth and weigh these advantages against the specific requirements of your project.

For tasks that don’t demand extended color depth, such as web graphics or certain digital displays, 8-bit depth may suffice and prove more practical due to smaller file sizes. The choice between 8-bit and 16-bit ultimately depends on the nature of your project and the desired outcome, balancing the advantages of color precision and image quality against considerations like file size and compatibility with specific tools and applications.

 

Which is better, 16-Bit or 32-Bit Depth?

Obviously, 32-Bit will hold many more colors. However, it is this author’s professional opinion that 32-Bit Depth is overkill, and leave you with huge files with little benefit. If you add a few adjustment layers, it can bring your computer to a severe slow down. Also, 32-bit removes options for just about every filter, and adjustment layer.

Overall, 32-bit depth may sound impressive with its capability to hold an extensive color spectrum, but in practical terms for Photoshop usage, it might be deemed excessive. My professional stance favors the more balanced 16-bit depth, which still provides a vast color range (281 trillion colors) without the potential downsides associated with 32-bit. Opting for 32-bit depth can result in significantly larger file sizes, potentially causing performance issues, especially when dealing with adjustment layers and filters. Moreover, the extensive color range in 32-bit may not yield substantial benefits in typical editing scenarios and imposes limitations on the functionality of certain filters and adjustment layers. Hence, for most retouching and editing tasks, the practicality and color precision of 16-bit depth often make it the preferred choice.

Just to be clear with my stance from the video, I still prefer 8-Bit because everything else is 98% overkill.

 

Should CMYK be 8-Bit, 16-Bit or 32-Bit Depth?

You can work in 16-Bit RGB, but since CMYK is the last step before sending the image to a printing press, it may as well be 8-Bit. Banding will need to be addressed then.

When working with CMYK images, it’s generally recommended to stick with an 8-bit depth. While 16-bit depth offers a broader color spectrum, CMYK is often the final step before sending an image to a printing press. In this stage, the file may as well be in 8-bit depth since banding issues, if any, will need to be addressed during the printing process. The constraints of certain filters and third-party plug-ins that operate exclusively in 8-bit mode also contribute to the practicality of using 8-bit depth for CMYK images. Although 16-bit RGB is a viable working space for editing, the conversion to 8-bit for CMYK ensures compatibility with the printing process and addresses specific tool limitations.

 

Why does Photoshop default to 8-Bit Depth, when 16-Bit is better?

The best reason is that several of the Filters, and 3rd Party Plug-Ins only work in 8-Bit. You see, Photoshop defaults to 8-bit depth due to historical reasons and practical considerations. Several filters and third-party plug-ins originally only supported 8-bit depth, limiting the software’s functionality in higher bit depths. The default setting ensures compatibility with these older features and external tools.

While 16-bit depth offers a broader color range and is beneficial for certain editing tasks, it comes with larger file sizes and potential compatibility issues with some tools. Adobe has maintained the default to 8-bit to ensure widespread applicability and smooth integration with various filters and plugins. Users can manually switch to 16-bit depth based on their specific needs, but the default setting caters to a broader user base and maintains compatibility with legacy features.

 

When should I use 8-Bit Depth Images?

There are a few times when 8-Bit is needed; JPGs can only be 8-Bit, when you need to deliver samples to your client, several Filters are only 8-bit, and when you need to convert a file to CMYK for a printing press. These are just examples off the top of my head, I am sure there would be some more.

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The choice between 8-bit and 16-bit depth in Photoshop significantly impacts the quality and precision of your image editing. While 8-bit offers practicality for certain scenarios like JPGs and client samples, the expansive color possibilities of 16-bit depth provide unparalleled flexibility for detailed and nuanced adjustments.

The “8-bit vs 16-bit” dilemma is not just a technical consideration but a pivotal decision that shapes the visual integrity of your work. By grasping the distinctions between these two depths, you empower yourself to navigate the complexities of digital editing, ensuring your creations achieve the utmost clarity and richness in color.

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This Digital Fundamentals Tutorial answers the question: What is the difference between 8-bit vs 16-bit, bit depth? If you would like to learn more about Photo Enhancement from a Professional Retoucher, I offer Adobe Photoshop Classes. Please contact me today, and I will be able to add you to the schedule too. If you would just like to watch online videos, The Art of Retouching Studio offers many Photoshop Tutorials for Beginners and Advanced users.