Sorry that I've been absent lately... but I’ve been attending to other things so that I can get this thing launched right, with my full attention. See you soon!

(By the way, knowing that I would be away for a while, I had suspended offerings of paid features- all content has been free thus far- and only offered free signups.)

Get ready!

Photo Credit

Air pressure at sea level is approximately 15 pounds per square inch, or PSI. This means that if you could weigh a square vertical column of air 1 inch by 1 inch wide at sea level, it would weigh 15 pounds!

Air gets thinner with altitude. If you are in Denver, Colorado, the “Mile-High City”, at an elevation of approximately 5,280 feet, that same column of air- your local air pressure- will weigh only about 12 pounds or 12 PSI.

Drive 90 minutes to Breckenridge, CO at 9,600 feet, and the pressure will be about 10 PSI, two-thirds that at sea level. Fifteen minutes south of Breckenridge, if you climb to the summit of Quandary Peak at 14,265 feet, your local air pressure will be about 8.5 PSI. The summit of Mount Everest at 29,035 ft? About 4.5 PSI.

The human body needs oxygen to survive. As the air gets thinner, so does its oxygen content. If you are at sea level and somehow manage to teleport yourself to sightsee at Everest's summit, you would not survive due to lack of oxygen.

Climbers ascending Everest typically spend weeks acclimatizing at increasing altitudes, including an extended period at Base Camp (~17,600 feet), plus several partial climbs up and down Everest before ever attempting a final assault- which is usually done with supplemental oxygen above a certain level. Some have done it without oxygen.

Acclimatization involves numerous bodily adaptations, including changes to your body’s oxygen-carrying red blood cells.

At a typical cruising altitude of 38,000 feet, the air pressure outside a jetliner is only 3 PSI, so we need pressurized cabins to survive. But just surviving isn’t enough, especially for the pilots, because we need lots of oxygen to be mentally alert and functional.

Mental alertness is definitely an issue above 12,500 feet.

When flying between 12,500 and 14,000 feet in unpressurized airplanes, flight crews must use supplemental oxygen masks if flying at those altitudes for more than 30 minutes.

At altitudes above 14,000 feet, a flight crew must use supplemental oxygen during the entire flight time at those altitudes.

Above 15,000 feet, each occupant of the aircraft must be provided with supplemental oxygen.

To enable us to breathe without oxygen masks, an airliner operates as a pressurized metal cylinder… just like a can of soda, or an aerosol can of deodorant or spray paint.

Pressuring that flying cylinder creates a lot of stress on the aircraft. In an airplane pressurized to sea level while flying at 38,000 feet, the pressure differential between the inside and outside of the plane would be 12 PSI (15 PSI inside vs 3 PSI outside).

That’s 12 pounds pushing out on every square inch of the aircraft, and means that the outward pressure on just a 12-inch by 12-inch window would be 1,728 pounds!

Due to this pressure differential, every time an aircraft ascends and descends, it also expands and contracts, leading to fatigue and stress fractures.

Thus, an aircraft's fuselage is limited to a specific lifetime, a maximum number of pressure cycles (flights) before being retired- a number typically between 35,000 and 85,000 cycles.

Let’s now come full circle to our original question. We’ve shown that pressurization stress can be tremendous across an entire aircraft. If a window just the size of a large iPad can have almost a TON of air pressure pushing against it… How do you mitigate this?

Airplane designers have long reached a happy medium by only partially pressurizing aircraft to a level that will be comfortable enough for almost all people.

Generally, when flying at 38,000 feet, the “altitude inside the cabin” - the pressure altitude- is set to 8,000 feet, instead of sea level.

This creates a pressure differential of only about 8 PSI, meaning that the outward pressure on that 12x12 inch window is now “only” 1,152 pounds- quite a difference, and quite a reduction in stress on the aircraft!

So, when you fly, you *do* feel the physical effects of climbing up to 8,000 feet above sea level. Hence, the popping ears!

PS- Newer designs, such as Boeing’s 787, are built mainly with lighter composite materials instead of aluminum alloys. This means they can accommodate higher pressures within the fuselage, typically cruising at cabin altitudes of just 6,000 feet.

Boeing states that “Altitude chamber tests show that because the body absorbs 8% more oxygen into the blood at this altitude, passengers experience fewer headaches and less dizziness and fatigue.”

And yes, they presumably pass gas and burp less, too- as these emissions are another side effect of being at altitude. Ever notice how quickly your soda goes flat when flying?

Article Archive

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Jet Photo Credit

Ancient Egyptians, Personal Branding, and Color Numbers

When it comes to defining colors, it’s all about primary colors, how colors are made, and a bit of math.

Primary Colors

In elementary school, I think we all learned that the primary colors were blue, red, and yellow, and that you could create any other color from combinations of these three. I certainly remember running my yellow crayon over my blue scribblings, to make green.

What they didn’t tell us is that there are two different sets of primary colors. The primaries you learn in elementary school are the subtractive primaries used for reflected-light items, like printed materials and crayon drawings. They also didn’t tell us that instead of blue, red, and yellow, the subtractive primary colors are truly cyan, magenta, and yellow!

In printing, you could make black by layering all three of these colors, but it is cleaner (as far as ink or toner thickness and alignment), and cheaper (one ink instead of three) to add black as a fourth ink color. (Black is also used to control the transparency of other colors, but I’m paraphrasing here).

These subtractive primary colors are denoted by the acronym CYMK (Cyan, Magenta, Yellow, blacK). These colors are also the reason for the term four-color printing!

The Additive Primaries

The other set of primary colors, the additive primaries, red, green, and blue, are used for items that generate their own light, such as computer screens, televisions, and stadium scoreboards. If you look at any of your screens with a magnifying glass, you’ll see the little red, green, and blue dots within each pixel. These primary colors are known by their own acronym, RGB. With this set of primaries, using transmitted light, adding all three colors together results in white, instead of black.

In the image below, you can see that adding any two primary colors together results in a primary color from the other set of primary colors, and that adding all three together indeed results in black (CMYK) and white (RGB)!

How Colors Are Made

Since we’re discussing number codes used in computer software, we’ll focus on the RGB color scheme, the additive primary colors. To make any particular color, you take specific percentages of red, green, and blue, and “mix” them together to achieve your desired color. Let’s look at an example.

Egyptian Blue is a rich blue color, used in artwork since ancient times, and considered the earliest known color derived from human-made pigments. Color-wise it is a combination of a 6.3% saturation of red, a 20.4% saturation of green, and a 65.1% saturation of blue.

These three numbers do not need to add to 100%, as the percentages only indicate the saturation/intensity of each primary. In other words, “How red the red in Egyptian Blue is, compared to a 100% saturation of red”.

Here’s a color swatch:

Other Examples

- 100% red, 100% green, and 100% blue would give us pure white, while
- 0% red, 0% green, and 0% blue would mix to pure black.
- 50% red, 50% green, and 50% blue mix to a 50% grey.

- Likewise, 0% red, 100% green, and 0% blue gives us pure green.
- But 0% red, 50% green, and 0% blue gives us a darker green,
because it’s not as green as 100% green!

Computer Numbers

Now, back to Egyptian Blue. This color’s identifying hex code (color number) is #1034A6.

In hex, or hexadecimal numbering, you still have the usual digits 0-9, but also A=10, B=11, C=12, D=13, E=14, F=15. You can ignore that for now, but that’s why you’ll often see letters in color numbers!

In the RGB scheme, inserting a space between each pair of digits in #1034A6 gives us,

10   34   A6

In other words, hex values of 10 Red, 34 Green, and A6 Blue.

But computers operate in binary, meaning in bits, which are other a “0” or a “1”. This is simply because an electrical signal is either off or on.

So, expressing the number #1034A6 in binary, the computer sees it as 000100000011010010100110.

A byte is a grouping of 8 bits. Let’s break up that long binary string into bytes by inserting spaces, as we did above with hex.

00010000 00110100 10100110 equals

00010000  Red, 00110100 Green, 10100110 Blue (Binary) which equals

10 Red, 34 Green, and A6 Blue (Hex)

Next, in binary, one byte can represent values from 0 to 255.
(Zero = 00000000 and 255 = 11111111)

To avoid pages of binary math lessons, let’s convert the values of the above three bytes to our regular human decimal numbers. Equating all three sets of numbers, we now have:

10 Red, 34 Green, and A6 Blue (Hex) =

00010000 Red, 00110100 Green, 10100110 Blue (Binary) =

16 Red,   52 Green,   166 Blue   (Human / Decimal)

We’re at the last step!
Since these numbers represent percentages of red, green, and blue, we have to remember that a byte has a maximum value of 255. For red, this means that the saturation of red is 16 out of 255, or 16 divided by 255.

So, for each primary color…

Red = 16/255 = 16 divided by 255 = 6.3%

Green = 52/255 = 52 divided by 255 = 20.4%

Blue = 166/255 = 166 divided by 255 = 65.1%

Sound familiar? These are the percentages we originally stated as defining Egyptian Blue! We’ve now gone full circle to show how a hex code color number represents the exact RGB percentages of that color. In our example, how the code #1034A6 equates to the percentages that define Egyptian Blue!

Now Try It! Build a Color! (Yes, please do it!)

The above is why when you use the “color sliders” in paint or photo editing software, the sliders allow a value from 0-255 for each RGB primary color! Go to your favorite software, and set the sliders to create a color of 16 Red, 52 Green, and 166 Blue. I’ll bet the hex code box will state color “#1034A6” and that you’ve just created Egyptian Blue!

How many colors can we define?

Recall that the binary color code resulted in a byte (8 bits) for each primary color, 24 bits in total. That’s where the term 24-bit color derives!

These 8 bits allow us to represent 256 levels (0-255) of saturation for each primary. Multiplying 256 x 256 x 256 means that there are a total of 16.7 million colors depicted by this scheme, from

#000000 (000000000000000000000000) for black,
to
#FFFFFF (111111111111111111111111) for white,
with
#1034A6 (000100000011010010100110) somewhere in the middle, for Egyptian Blue, just one of those 16,777,216 possible colors!

PS- The CMYK value for Egyptian Blue is 90, 69, 0, 35. Every editing tool (that I’ve ever seen) will resolve CMYK, RGB, and hex code numbers for colors. Hex codes seem to be the most portable and most straightforward to communicate, and anyone can extract CMYK, RGB, and many other color reference schemes out of that one number.

How is this useful?

Let’s look at a few ways that understanding how color numbers work and how colors are built can help you!

• You can now ensure that when you are branding yourself, perhaps inclusive of a website, social media presence, logo, and more, that you have the exact colors you want, and that your colors are exactly the same between all items.

  With the knowledge of color codes, you’ll know to specify the hex code color number of the colors that you love, and ensure their use everywhere! Egyptian Blue #1034A6 is the same color everywhere, after all.

  Check out this link to see your favorite university or pro sports team’s official colors, and you’ll get an idea of how the pros specify color codes!

• When seeking out colors, remember the relationship between colors and number values to find the exact colors that you want. For Egyptian Blue, you would enter #1034A6 into your paint or photo editing software, which would become 16 Red, 52 Green, and 166 Blue on your software’s color sliders. Realize that as you adjust these values up or down in value, that you can “mix” more or less red, green, and blue into the color.

• In your paint or photo editing software, this knowledge will also help you understand the application of a “color picker” tool to duplicate or borrow a color that you like! A color picker tool identifies the color code for the color it is pointing to. You can bring an image or swatch into your paint or image editing software, place the color picker tool over the color that you like, and grab that color code to duplicate that color.
  Note: There are considerable accuracy limitations within certain image formats. This might be the subject of another post, someday!

• Understanding color numbers, you can avoid the risk of your eyes being fooled when selecting colors off of color choosers or color wheels within varying sources. They all may look the same on the screen, but when comparing the finished items, they may not match due to differing hex codes.

Tips:
Note that colors may also vary across different display screens, depending on the brightness/contrast and the “warm vs. cool” color temperature settings of each display. It’s another reason for the use of color codes once you find the colors you like!

Printed items can vary depending on the medium. Think glossy vs. matte paper, cloth, metals, plastic, and more. But at least you’ll have a standard reference via the use of color codes! In a critical color matching situation, a printer will often be able to recommend how to tweak a hex code in their printing process to get that matte business card to match that glossy folder visually.

Just For Fun

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Color Spectrum: Main Photo Credit

If you search for (or click on) a location in Google Maps, the map coordinates of that location are provided as a Plus Code, instead of a latitude and longitude. Why?

Many of us take our street addresses for granted. In many areas of the world, including developed countries, there are locations that people, mail, and services need to reach without the benefit of named streets and roads. These locales range from remote areas to densely populated cities where street addresses are not assigned, whether the roads are named or not. In these areas, homes and businesses can be found only via directions relative to often impermanent landmarks.

These direction-based "addresses" are often literally, "the blue building, 100 meters east of the city bus terminal" or "the hotel located 150 meters north of Joe's Restaurant". You'll see a real-world example in a second.

In mapping, latitude and longitude have long been used to define locations that don't have addresses, but is there really anything less descriptive than "N9.938437 W84.109188"? In comparison, this is where Plus Codes can shine, pinpointing areas just as accurately but more expressively than latitudes/longitudes.

Plus Codes divide the Earth up into grids averaging just a few yards/meters in size, with each grid able to become a de facto street address, expressed as a grid number along with a few words identifying the neighborhood or district. Picture each Plus Code as similar to a U.S. Zip Code, but granular enough to be less than the size of a house.

I'm hoping that each of you hangs on through the short videos at the end, as it's truly amazing to see how Plus Codes are actually changing lives. But learning about Plus Codes is also vital if you use geo-coordinates for any mapping or navigation tools. Many online tools and apps do not yet support both Plus Codes and latitude/longitude, so understanding them, and even knowing how to convert them is very useful.

A Real-World Example

Let's look at an example in Costa Rica. This country doesn't necessarily assign street addresses, even within its busy metropolitan capital, San Jose.

This McDonald's restaurant listing on Google Maps has a street address listing of (translated from Spanish) "On the west side of National Stadium, diagonally across the street from Scotiabank, in the La Sabana district, San José province, Costa Rica." Sending them a postcard from your vacation? Remember that address. That's how you'll get it there.

Now, look at the bottom of the listing. You'll see a plus-sign-shaped graphic made of blue dots, with the following description, "WVQR+98 San José, San José Province, Costa Rica". This is the Plus Code location for this McDonald's. The code states it's on grid WVQR+98, in the city of San Jose, San Jose province, Costa Rica.

To illustrate the actual grid location and size, we can go to the website plus.codes and paste this code. It returns the following rendition of the same map, with the actual physical grid for that Plus Code shown in red. You'll see that the grid is indeed small.

If you look at the left-hand column, you'll see this tiny grid represented in 3 different ways:

1. WVQR+98 San José Province, San José, Costa Rica
   The Plus Code

2. 66XQWVQR+98
   An equivalent fully alphanumerical version of the Plus Code. The 66XQ equates to "San José Province, San José, Costa Rica." For remote locations not associated with a named place, this would be the code version on which to depend.

3. 9.938437,-84.109188
   Latitude/Longitude
   Pro Tip: This lat/long conversion is extremely useful if you want to program a Google Maps location that doesn't have a street address into a navigation tool that doesn't support Plus Codes!

Looking forward, it appears that the island nation of Cape Verde, portions of Kolkata (Calcutta) India, and the Navajo Nation are accepting Plus Codes as mailing addresses. And I haven't even touched on other essential uses… having a Plus Code as an address in an address-less locale also helps with registering as a voter, obtaining a bank account, directing emergency services, and medical/social services outreach. I'm sure there's more to come.

PS- I used the example of an address-less, yet quite visible fast food outlet on a capital city street corner. Now imagine densely populated unnamed streets and alleyways within global inner cities, and you compound the challenge even further- likewise for remote locations. The first few short videos are impressive in illustrating how Plus Codes are actively changing lives in places like these for the better.

The last video is for those interested in learning how to access Plus Code grids on Google Earth. Please enjoy!

Over my career(s) as an engineer, advertising/marketing guy, and researcher, I’ve written technical items for professionals and laypeople. I’ve also written hundreds of position and strategy papers on subjects for those usually unfamiliar with said subjects.

Here, I’ll be writing pieces on:

• Subjects that I know like the back of my hand, where I could write dozens of pages of details.

• Topics where I know just enough to be dangerous!

• I’ll also include subjects where I’ll be communicating almost all I know. Still, I thought it would be fun to pass it along to learn even more together.
  

Definition of “paraphrase”:
Noun- rewording for the purpose of clarification
Verb- express the same message in different words (Wordnet. Princeton Univ.)

I’m trying to write in a casual style here. As such, I will heavily employ paraphrasing in its most real sense- that endeavor to reduce complex ideas to something easy to understand…

Those as knowledgeable or more knowledgeable than myself in any subject may find that I have oversimplified, used an imperfect comparison, or glossed over some important detail, in their opinion. Please forgive me. I’ll be trying the best that I can.

As I’ve said, I’ve done this kind of thing before, but I’m far from perfect. The one thing I will do is try to provide concise, fun, educational pieces that get the concept across to anyone without specific knowledge on the subject.

I’ll always at least be genuine. After all, I’m just a gorilla with a keyboard.

Thank you for reading, and hopefully, subscribing! Enjoy!

Copyright © 2020 Richard Velez
The Why? Digest™, The Why Digest™, Why? Digest™, Why Digest™

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