So, my 14-year-old, Kate poised this question:
“Could we, using cloud seeding technique, change the color of clouds?”
Damn fine question, says I. I knows who to ask.
So could we hit clouds with some sort of particulates that would make them blue or green or whatever? Quote Kate, “If we could, why WOULDN’T we?”
Bonus round: Would it change the color of any precipitation, should such occur?
It is indeed a great question but I think the answer is no - something to do with the wavelength of light going through water molecules will always make clouds seem white/gray to us. I found this site which asks the same question and has an answer which sounds reasonable:
http://littleshop.physics.colostate.edu/tenthings/Why%20are%20clouds%20white.pdf
Let’s be 14 again and assume we could color clouds. What color schemes/patterns would you recommend?
I adore you all, even while soaking in disappointment.
So even if we scatter lightweight pigment the clouds stay white/gray. That bites because - let’s face it - it would be awesome to look up.
Ideas posited by Kate:
But there must be others. And I’m still open to ideas for how to overcome this pesky ‘physics’ thing.
Green sunglasses?
Maybe they’re already there. How would we know! 
It would take many tons of particulate to make a perceptible change in the color of clouds, and it will all eventually fall out on the ground. I think the really good pigments are made from compounds of heavy metals, which are not cool things to have raining down. (Due to toxicity, not the danger of being clunked on the head by them.)
The best things in life are rare, so just wait for a good sunset or sunrise.
A powerful searchlight aimed up at them might do it.
Or she could make her own: Technology | Engineering | Innovation - Commercial LED Lighting | Elemental LED
I love that kids ask questions like this:)
Lasers.
Which, arguable, are already used for this.
You know those trails jetliners leave behind them in the sky? That’s how the gummint will color the clouds. Right now they’re still experimenting with the right dyes to use. They tried food coloring, but that didn’t have enough saturation to make it visible from ground level. Easter egg dye worked better, but it had to be mixed with vinegar, which caused the nozzles to rot out.
The search continues.
During hailstorms and tornados, I’ve seen clouds take on a greenish hue.
Color is an interpretation made by the mind. An object absorbs light of various wavelengths (or all in the case of glass) and reflects light of other wavelengths based on how the chemicals in the particular matter react to the electromagnetic spectrum. We see light that isn’t absorbed, it is reflected in wavelengths that are not absorbed. Those wavelengths do not have “color” but do come to our eyes and engage in a similar process of going through our eye lens and hitting the retina and having a reaction when absorbed by the retina. No “color” involved. Our brain assigns color.
But we have pretty well mastered the technique of making people’s brains assign color. Like stop signs. Which convincingly pushes the idea of color into man-made territory.
You could “color” clouds, as noted, by illuminating them with colored light. This happens naturally at sunrise and sunset, when you can see yellowish, orange, or red clouds. As noted, you could use lasers, or spotlights with colored filters over them.
Another natural way clouds are colored is when cirrus clouds, which consist of ice crystals, refract that light. If the crystals asre large venough*, the light can be prismatically separated at certain angles. Parhelia, zenith arcs, Lowitz Arcs, and lower tangent arcs all produce such interesting “rainbow”-like color separation
https://search.yahoo.com/search;_ylt=AwrBTzkPt8JTIkYAOz1XNyoA;_ylc=X1MDMjc2NjY3OQRfcgMyBGJjawM5ZG84MmM5OXMwamM0JTI2YiUzRDMlMjZzJTNEbmsEZnIDeWZwLXQtMjU3BGdwcmlkA0VPYU91ZXd2VHZpZjM0aUNSTGNvaUEEbXRlc3RpZANBRE1SJTNEU01FNTg3JTI2QVNTVCUzREFTU1RDMSUyNkxPQ01MUiUzRFZJUDA0OCUyNlJBTVAlM0RSTVAwMiUyNlVJMDElM0RWSVA0NDQlMjZVTkklM0RSQ0YwNDMlMjZVTkkyJTNEU01FNTAwBG5fcnNsdAMxMARuX3N1Z2cDNARvcmlnaW4Dc2VhcmNoLnlhaG9vLmNvbQRwb3MDMARwcXN0cgMEcHFzdHJsAwRxc3RybAMxMwRxdWVyeQNzdW5kb2cgaW1hZ2VzBHRfc3RtcAMxNDA1MjczMzM0MjQ0BHZ0ZXN0aWQDVklQNDQ0?gprid=EOaOuewvTvif34iCRLcoiA&pvid=NwvWOjk4LjGW4QJiU8BNhADQMjQuMlPCtw__uzwo&p=sundog+images&fr2=sb-top&fr=yfp-t-257
As for putting coloring matter into the clouds to do the scattering, I don’t think you could get sufficient absorbtion to color the reflected light. I might be wrong, and would be happy to be proven wrong.
a sort of related issue is that if you get enough of the liquid suspended in the air, you can cause unusual ranges of wavelength scatter, producing blue or green moons and suns. This has sometimnes happened after forest fires leave suspended droplets of organic liquids in the air, and is (in part) the origin of the phrase “once in a blue moon”
Blue and green moons and suns HAVE been photographed, from time to time. But most photos you’ll find on the internet are photoshopped. I think this one’s got a real picture in it:
“Observation of a Blue Sun over New Mexico, USA on 19 April 1991” R. Horvath, G. Mitzig, O. Preining, and R.F. Pueschel Atmospheric Environment 28 (4) 621-630 (1994)
Silver lining.
If you’re talking 14 year olds it would probably break down by gender.
Girls: ponies and unicorns and flowers.
Boys: grossly exaggerated human body parts.
Or, if you were my fourteen year old, pictures of David Tennant in his Doctor Who outfit. That and a lot of black. LOTS of black.