Ghost White and White smoke are NOT the same colour
Note that I personally can't spot the difference... since all shades of one colour look pretty identical to me, but still, there is a difference.
One thing you're (probably) familiar with is a "colour picker", or a "colour dropper".
Many of the editing tools you might have used (from image editors to PDF editors) include these features. The ability to either pick a colour from a huge pool of them; mix and match using hex codes, RGB settings or other tools; or even using that little dropper that lets you select a colour on your screen (in case you don't know the colour's name/number/code).
I'm almost positive that some of you might not know about the dropper, so here's a quick GIF to demonstrate that.
Using the dropper tool, I'm able to hover over any pixel on my screen and let the dropper figure out what colour I'm hovering on. Again, this is very useful when you don't know the name of a colour. In the case above, I hovered over my desktop wallpaper, and got the colour #6A7573, which is apparently a shade of the colour "Rolling Stone" (who knew?).
Now, there are many colour-picker apps for your computers, so this tech-letter won't focus on that specifically. What I will talk about is a colour-picker app for your iPhone (yes, iPhone-only).
As the image above states, Cone is a colour-picker for the real world.
Instead of you being limited to your computer screens, Cone allows you to point your iPhone (or iPad)'s camera at... well, anything, and figure out what colour it is you're seeing. This is one app I've been meaning to try for a couple years now and once I finally did, it was revolutionary (I might be exaggerating a bit, but you get the point).
If this 1-paragraph explanation wasn't enough, there are several noteworthy features I could (and will) mention.
What you're seeing above is what the app looks like once you open it (in the case above, on an iPad). I'm going to quickly run through the options you see on screen.
For starters, I'm pointing at some hand sanitiser (ignore that terrible brand name). That small white circle-outline on the right side of the bottle is the actual colour picker. I can either move my camera around, or move that circle around with my finger. When I do, the colour (in this case, "Persian Green", updates automatically), it even gives you the hex code (#01B5A3).
Since the camera is constantly moving, you're able to freeze the screen (check out the snowflake icon on the bottom). This lets you freeze the screen, and therefore the colour, wherever the colour-picker currently is.
You can save each colour you pick in a "colour library", for future use. You can enable your phone's flashlight (lightening icon) for night-time use. You can even enable colour-blind mode (so in the example above, instead of "Persian Green", it would just say green).
Lastly, like in the image above, you're also able to upload a picture from your camera roll and identify the colours on it. In this case, the colour picker identified that part of the aeroplane wing to be "Kilamanjaro", or #3A352E.
All in all, Cone is a great app if you're an artist of any kind or simply have the need to identify colours in the real world (specially if you plan on painting walls any time soon!). This app also comes with an Apple Watch companion that syncs colours in real time. You can add colours manually, organise them, and even share results with others.
Cone is an iOS-only app, and costs $4.99 for lifetime access.