Reddit reviews 1M/3.3FT U-Shape Aluminum Channel for Surface and recessed LED Strip Installation, Slim Compact Design Aluminum Profile with Oyster White Cover, End Caps and Mounting Clips - U02

If you could find some way to diffuse the lighting a bit I think itd take it to the next level. Because how bright the picture makes it seem, I can't tell if its just a standard adhesive LED strip or what

But something like this would soften the lighting and give you clean straight lines

The area looks very cool though

Not tape, but usually if you want to diffuse an LED strip and have the installation look pretty you would use a plastic or aluminum channel with a diffusion cover. Something like this. On-the-cheap you could put the strip in acrylic square tube and then sand or sandblast the outside to frost it.

You can also use white fabric or vellum - remember that the farther you put the diffusion the better blending you'll get.

I used these when I did LED strips under my cabinets. Theres corner ones too https://www.amazon.com/gp/product/B00F9Q602M/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

First, leds strips are made the cheapest way possible so there is a good chance that some of them will be damaged right out of the package. With that said, measure the length you need and buy double that just to be sure.

Length doesn't dictate the brightness of the leds, (which are wired in series) the power source will. Typically the 12v ac adapter that gets provided for these led strip packs just isn't enough to keep the leds at 12v due to voltage droop. To fix this, just get a better quality power supply. Even trying for a slightly higher voltage, and adding a resistor between the source and the lights.

For light diffusion, try this:https://www.amazon.com/U-Shape-Aluminum-recessed-installation-Mounting/dp/B00F9Q602M

Although, if the light will be viewed indirectly, you probably wont need it.

Correct. The Arduino can only output a few mA (see its specification), so you need to use transistors (eg MOSFETs) - probably one for every channel (R/G/B).

I recommend you work in stages:

• Decide what topology you want. Do you want to have one controller controlling all your strips at once? Should they all be the same colour? What inputs should it respond to (button presses, timers...)?
  
• Build a prototype of your MOSFET transistor stage - use a breadboard and wire it up so you can connect the Arduino and your power supply at one end and the LED strip at the other.
  
• Connect a short length of LED strip to your Arduino through your transistor stage, and start writing some basic Arduino programs to gain experience. There are a ton of tutorial and code samples, just use your favourite search engine.
  
• As for power supply, determine what input voltage and current your strips need, and buy an appropriate-sized power supply.
  
  If you give us more details about what exactly you're planning to do we may be able to give you more concrete answers, but your post is very vague.
  
  Also, consider how you want to install the LED strips. Usually indirect lighting works best, but this means you can't just stick them on the wall/ceiling, but have to recess them behind something (e.g. a TV, on top of cupboards) so that you're never looking at the strip directly, but it's illuminating a wall/ceiling instead. Keep in mind that the strips can produce a moderate amount of heat - I recommend you look into metal U-shaped channels (example) to act as heat sinks.

I think it's a combination of different photography and possibly different LED spacing and diffusion.

If you want a nice smooth light, get the highest-density strip you can, and put some sort of diffuser on it. These are purpose-made but anything that makes the light go through some kind of frosted effect will do the same thing. You could even put them inside clear tube and spray it with glass frosting paint.