Proper use of noise in textures?

[NerdKoopa]

When is it appropriate to use picture noise in your textures to add detail? For example, here are my custom wall and door textures with and without noise.
http://imageshack.us/photo/my-images/717/screenshotdoom201208181.png/
http://imageshack.us/photo/my-images/825/screenshotdoom201208181.png/
The orange parts represent metal, the black parts represent plastic, and the white parts that are noised in both pics are representing fiberglass wallpaper. I'm not sure if adding noise to the metal and plastic parts was a good idea....

[printz]

Generally I add noise when the texture of the real material is noisy. Metal and plastic are smooth; wood's texture follows the fibres' directions.

[NerdKoopa]

But when I've studied Doom's textures, there are rarely fully smooth metallic surfaces. Is it because they are supposed to look worn and dirty? I want these particular textures to look new.
EDIT: fixed some typos. That's what you get for writing in a hurry :/

[schwerpunk]

I'd say at lower resolutions, you pretty much have to add noise to give your textures depth (either that, or chop up the shading a bit). Unless you don't mind them looking like Mega Man sprites.

About your textures looking 'new,' they still look clean, but more like fibreglass than than an impossibly flat, plastic panel.

[NerdKoopa]

I'm still not sure which one of these pics is better. The noiseless orange looks like something out of an NES game, but the one with noise looks like a freaking Dorito chip. Maybe I should add the noise by hand and use more vertical strokes?

[RestlessRodent]

NerdKoopa said:

I'm still not sure which one of these pics is better. The noiseless orange looks like something out of an NES game, but the one with noise looks like a freaking Dorito chip. Maybe I should add the noise by hand and use more vertical strokes?

What is the texture of the metal you are recreating?

It is obviously painted orange so, in this case:

Is the orange paint really thick or really thin? is it glossy or matte? Is it smoothly applied to the surface or is it messy? Is it brushed on, spray painted, or electromagnetically applied?

These questions should help what to do in these cases.

[NerdKoopa]

Well, the material I'm looking for should look like something that woudn't look out of place in an old UNIVAC III computer mainframe.
http://www.bitsavers.org/pdf/univac/univac3/photos/UNIVAC_III_2.jpg
My map will eventually look like a neo-retro version of that. Here's a pic of the testmap where I mess around with the textures.
http://img99.imageshack.us/img99/2405/screenshotdoom201208181.png

The visual style will not be your usual Doom stuff, that I can tell.
EDIT: Forgot to mention, the computers seen in the pic are animated.

[EarthQuake]

The textures in the last shot don't look terribly bad, but the hard lines (especially the diagonal ones) stick out a bit too much. Try to anti-alias those a bit, and for the rest, use different shades that are still close, but give more definition to the texture.

Take a look at TANROCK2, TEKGREN, STONE2, or even the panels in STARGR1 for how you might want your "noise" to look. I mean like really zoom in and examine how color variation is used. For a smooth plastic-like material, I would advise against using the type of noise found in METAL or STUCCO or MODWALL.

[NerdKoopa]

Thanks a bunch! I'll look into it. :) When I eventually get to making the actual map, I hope people will not rage over the unusual art style.

[NerdKoopa]

I did some further improvements on the textures.
http://imageshack.us/photo/my-images/89/screenshotdoom201208191zt.png/
http://imageshack.us/photo/my-images/844/screenshotdoom201208191.png/
Are they starting to look any better?

[schwerpunk]

Much better, in my opinion. Though perhaps a little too uniform? I'm unsure, because I'm not a [texture] artist.