Adding two bits

Accurate color. That’s an important thing. Herein lies the tale of adding just two bits.

Color as represented in a computer is typically made up of a 24-bit composite value arranged as 8 bits each of Red, Green and Blue (RGB). 24 bits allows for 16,777,216 combinations – and that’s enough for anything, right?

Let’s see about that. Human perception is believed to encompass 12 – 15 ‘stops’ of dynamic range from light to dark; thus at least some among us may be able to detect a full 16 bits just of light to dark. 24-bit color allows for 256 values (light to dark) of each of the three colors… hmm… 256 values is only 8 bits… only a fraction of what we can actually perceive.

Before looking to increase the range, the question is, is it really necessary for most computer applications? No. Historically website builders worked within a limited “web-safe” color palette of just 216 colors. The first two iterations of the iPhone supported 18-bit color (262,144 colors); this is still true of most feature phones on the market today – and of many older model desktop displays (including the 20-inch iMac).

Today pretty much everything outside of a few budget notebooks are using 24-bit displays, even if much of the content we view doesn’t need so many colors. But what about the applications where the extra color depth is important?

One solution might be to go for the maximum — make all the paths 16 bits; but this becomes a sizable nightmare rather quickly. 48 bit color is certainly doable – but you’ll need a very fast machine and loads of memory and Adobe Photoshop to pull this off… and you’ll have to do your work partly blind, because no [affordable] display hardware is capable of showing you the full 48 bits.

But we can quadruple the number of available colors by merely adding two bits to each of our three colors! And 30-bit is much easier for our hardware to handle.

Still, the entire workflow has to support 30-bit operations. Source – my cameras support either 12 bits/channel or more; 36 bits input. Processor is rated to handle 64-bit operations. Video card supports 24-bit, 30-bit or 48-bit output… and the newest monitor also operates in 30-bit mode. Software support – Adobe Photoshop CS5.5 handles it (admittedly a bit awkwardly), as does certain industry-specific* modeling software.

I’m doing this in Windows 7, which supports a 30-bit color path if you turn off “Aero.” If you’re on a Mac, complain to Cupertino because your O/S doesn’t support 30-bit colors, even if [some of] your hardware does.


* NDAs are “fun.”

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On changing displays

One evening a few weeks ago I was busily working away on the computer and without any warning at all, there  was a sharp buzzing sound, a soft “pop” – and a blank display. I spent a good twenty seconds in the first portions of the “utility power is out let’s start shutting down the non-essentials” routine before it hit me: only the display had gone out.

As usual, the timing was impeccable. December 24th, the sales were over, ok, hook up the [garbage but it works] monitor from the server and start seeing what’s in stock where and for what price. Before long the choice is down to just a handful of items… and by 2:15 that afternoon the order is placed and the waiting game begins.


The display which died was a Dell 2407FPW – in service in July of 2006, so I got about 8 1/2 years out of it. In the summer of 2006 it was considered a high-end monitor; one of the few LCD displays with color accuracy comparable to the monster (27-inch Eizo) CRTs I’d been using. The Dell was a “pivot” monitor – which can operate in landscape (widescreen) or turn to portrait orientation (very useful for page layout work).

The video card on this box is a FirePro v5700 – nice mid-range workstation graphics, can output to DVI or Display Port with adapters for just about everything.

The choice boiled down to… Dell U2413 or Asus PA249Q.

Both are 24-inch 1920×1200 IPS 10-bit LED-lit displays. Prices are within a few dollars of each other. Reviews… the major sites are a draw; minor differences noted between the displays – mostly concentrated on preset “movie” modes – but the user reviews tell a different tale.


December 29 came and UPS brought the monitor right up to the door, and after getting it out of all the packing materials, and reading the calibration report, and re-routing the cables and getting the soundbar attached… it works!

And all is good, and now I’m running with a 30-bit color pipeline (with three programs only but this is for another post), calibrations are good, I can see clearly now…

I chose the Dell.

Removing IPv6 (aka Microsoft Teredo Tunnel Adapter)

I can hear the shrieks already (“Why would you do this?”) from the purists.

The reality is, for the foreseeable future (say through 2018), IPv6 is going to be an item for the professional fringe. For the home user, and small office/home office user, IPv6 has little if any utility. In fact, even if you have it, all it’s doing is slowing down your connections – as time is wasted attempting to establish IPv6 connections.

Instructions are based on Windows 7… usual disclaimers apply (your mileage may vary; no animal testing performed; not responsible for damage; etc).

Here are the steps, illustrated. (Click on any image to get a larger version)

1) ipv6-01

2) ipv6-02

3) ipv6-03

4) ipv6-04

5) ipv6-05

I removed IPv6 from this machine years ago; my ISP doesn’t support it… and it’s just more “noise” on the line.