Many photographers have been buying expensive wide gamut monitors in order to take a full advantage of their ability to display over a billion of colors. What many do not realize, is that their actual workflow is most likely limited to just 16.7 million colors due to software and hardware limitations. How does one achieve a true 10 bit per channel, or 30 bit workflow? What are the advantages and is it worth the effort? To answer these questions, I decided to dig into the 30 bit photography workflow in detail and explain its advantages, disadvantages and also discuss its future.
With computer monitors advancing year after year, we are now seeing excellent wide gamut options for even those of us that are on tighter budgets. The next step in resolution is 4K monitors and we will start seeing solid, true 4K panels on the market fairly soon. With all this new technology making its way into our homes and businesses, it is crucial to understand how these new technologies can improve the results and help us get the best out of our equipment choices.
1) What is a 30 Bit Photography Workflow?
If you are not a geek who understands things like bit depth, ICC profiles and other related jargon, you probably have no idea what a 30 bit photography workflow stands for. Well, don’t worry – for a while, I had no idea either! Most of us take pictures and don’t even have a clue what the “14-bit RAW” option in our camera really means! When a monitor displays an image, each displayed pixel is represented by a certain number of colors. Since the basic unit of information in computing is bits, this number is often represented as “bits”, or “bit depth” (sometimes also referred to as “color depth”). Bit depth is represented as number 2 with an exponent. For example, 2-bit color is 2² = 4 total colors. In the early days of computing, monitors used to be monochrome, which is basically 1-bit (21 = 2 colors for black and white). If you are old enough to remember EGA monitors, those used to be 4-bits with only 16 total colors. Nowadays, most screens feature 24-bit “true color” panels that are capable of producing a total of 16,777,216 colors. Because colors are made from three main colors (Red, Green and Blue), the 24-bits I am referring to represent the total number of colors, which translates to 8 bits, or 256 colors per color channel (28). So if you do the math, that’s equates to 28 x 28 x 28, or 256 x 256 x 256 = 16,777,216. So if you hear someone mention “8-bit display” today, keep in mind that they are referring to 8 bits per channel, which is a 24-bit screen with 16.7 million colors.
In comparison, a 30 bit monitor means 10 bits per channel, which is 210 = 1024. That’s 1024 colors per channel, so if we do the math 1024 x 1024 x 1024, that’s a total of 1,073,741,824 colors, which is 64 times more colors than a true color display! It would seem that a slight increase from 8 bits to 10 bits would only slightly increase the total number of colors, but as you can see, that’s certainly not the case. So if you ever wonder what you would gain by shooting a 14-bit RAW file instead of a 12-bit, we are talking about 4.4 trillion colors vs 68.7 billion, again 64 times difference in comparison! Hence, a true 30 bit monitor is significantly better in displaying more colors than a typical 24 bit monitor.
In short, a 30 bit workflow is aimed at displaying that many colors on the screen for you to see and work with. And that’s where the problem lies, because it is not as simple as it may sound!
3) 30 Bit Workflow Components
In order for you to be able to see over a billion colors in true 30 bit depth, you not only need a wide gamut monitor, but you also need other hardware and components that actually send the proper color information to the screen. First, it starts with the operating system of your computer that must be able to support outputting 30 bits. If you are a Mac user, you can stop right here, because Mac OS still has no support for 30 bit color output. As of July 2014, the latest version of Mavericks 10.9.4 is only capable of outputting 24 bits. This means that you can only attain 30 bit workflow if you are a PC user (both Windows 7 and 8 have built-in support for 30 bit output, but if you use Windows 7, you will have to turn off the Aero theme).
Second, you will need a professional graphics card such as “NVIDIA QUADRO” that has software support for 30 bit output. Although both NVIDIA and ATI video card hardware can be used for 30 bit output, NVIDIA drivers seem to be more stable for this purpose. Personally, I use an NVIDIA QUADRO K2000 video card to output to two Dell U2413 monitors (dual screen setup). Special video card drivers specifically designed for these cards will have to be installed, since 30 bit support has to be supported by both hardware and software.
Third, you will need a special cable type that can actually handle that much data output. An old DVI cable won’t work – you will either need the latest generation HDMI cable (HDMI 1.3 standard), or DisplayPort / Mini DisplayPort cables. Personally, I use DisplayPort cables – you can even daisy chain those between multiple monitors!
Fourth, you will need imaging software that can support 30 bit output. Unfortunately, this is where the biggest issue is today – aside from a small number of software packages like Adobe Photoshop CS6 / CC / CC 2014 and Zoner Photo Studio, there is no other software on the market with 30 bit support. As far as I know, Lightroom 5 still does not have 10 bit support right now and just applies dithering to make images appear smoother.
Lastly, if you will obviously need a good wide gamut monitor that can handle more than 8 bits of data. And this is where things can get tricky as well – the Dell U2413 monitor that I referenced above and personally own, for example, is not a true 10 bit monitor – it achieves 10 bits by using an 8 bit panel + FRC / dithering. True 10 bit monitors are very expensive in comparison and only a small number of companies like Eizo offer them. Sadly, this “cheating” by using dithering does not just apply to 10 bit screens – many cheaper 8 bit monitors are not true 8 bit panels either, utilizing a 6 bit panel + dithering. So don’t be too frustrated if you own an 8 bit wide gamut display, since 8 bits of native colors is still way better than 6 bits plus “emulated” colors! Also, don’t forget that your monitor must have proper digital inputs for DisplayPort, Mini DisplayPort or HDMI 1.3.
4) Adobe Photoshop 30 Bit Display Option
Once you have all of the above components and you are ready for the 30 bit workflow, you will need to make sure that your version of Photoshop is going to work. If you are not a Creative Cloud subscriber, keep in mind that CS5 had limited support for 30 bit workflow and only CS6 and above have full support for it. The initial versions of Adobe Photoshop CC had some issues with 30 bit output, but those were resolved with patches. The latest Photoshop CC 2014 has full support and works quite well.
By default, Photoshop does not automatically detect and output 30 bits to your screen – you must turn that option on first! Navigate to Edit -> Preferences -> Performance, then click the “Advanced Settings” button under “Graphics Processor Settings”. You will be presented with the below window:
Make sure to put a check mark in front of “30 Bit Display” and you will be good to go!
5) How to Identify 30 Bit Output?
You might be wondering how to check if your monitor is actually outputting 10 bits of colors. There are two methods to find out. The first method involves creating a black and white gradient in Photoshop. First, create a new image with the below settings in Photoshop:
Once the image is open, select the Gradient Tool (G), then left-click drag your mouse from left to right (or vice versa), starting from one side of the image all the way to the other side. If you want to keep the gradient straight, hold the shift key as you do this.
With the gradient going from black to white from one side of the screen to the other, you should be able to see very smooth transitions. Take a look at the below image (make sure to open the image fully, or open it in a new window):
If you have a wide gamut display, the above image should appear smooth in your browser. And if you have a low quality display, here is what it can potentially look like:
If you see vertical lines that separate different color shades as above (also known as “banding” or “posterization”), then your screen is most likely limited to 8 bits. If you see a lot of posterization, it might not even be 8 bits…
The second test is a bit better, since it does not span so much black and white – it is mostly gray. Download this file, unzip the PSD and then open it up in Photoshop. If the whole image looks smooth, you are in 30 bit workflow. If you see those lines / posterization, then you are working in 8 bits or less.
On my properly calibrated Dell U2413 using X-Rite i1Display Pro (custom Dell drivers and hardware calibration), the file appears quite smooth with no posterization visible, which means I am getting 30 bits. Unfortunately, I cannot show you my screen as it won’t show the image properly on your monitor, but hopefully you get the idea.
6) Is it worth it?
Seeing all of the above, you might be wondering if a 30 bit workflow is worth the headache. There is definitely quite a bit of work involved in making this all work and it is not a cheap proposition by any means. If you were to ask me a year or two ago, I would definitely recommend to stay away from it. Back then, Photoshop support was quite bad and good panels were extremely expensive. However, things have changed since then for PC users for the better and now I am starting to see more people adopt a 30 bit workflow to get the best out of their images. For me, given the fact that I already own a decent IPS wide gamut monitor and the cost of getting a professional graphics card was fairly reasonable, I decided to go for it and enable the 30 bit support. While it did not make a drastic change in my workflow, I can now see more colors and I have more options for post-processing images, especially when I need to recover shadow or highlight details. Skies do not appear posterized anymore due to 8 bit limitations, which is pretty noticeable when working with landscape shots.
What about the future? Well, 30 bit workflow is far from being mainstream at the moment, but I believe that we are heading there, albeit slowly. With more people adopting high quality wide gamut monitors and increased interest in seeing more colors, I believe that more software companies will soon start offering 10 bit support. Apple has been dragging its 30 bit support for a while now and considering how widespread the use of Apple products is among the photography community, it is another big reason why adoption is very slow.
Let me know if you have any questions! We will be writing more about colors, calibration and bit depth in the next few weeks.