Monday, December 28, 2009

Luminescence

When hot or flaming objects give off light it’s called incandescence. But some things give off a glow at cool temperatures through a process called luminescence. There are many causes—and many artistic effects—you can create.

In Dinotopia: The World Beneath, (1995), large caverns beneath the island are lit by glowing algae, "sunstone" crystals, and ferns. Although higher plants in our world aren’t known to give off their own light, many things objects are luminescent.

Bioluminescence

Organisms that can produce light live mostly in the ocean. They include fish, squid, jellyfish, bacteria, and algae. In the deep sea beyond the reach of light, the light patches function to lure prey, confuse predators, or locate a mate.

Land animals that emit light include fireflies, millipedes, and centipedes. Some light-producers are activated by mechanical agitation, creating the milky light in the ocean alongside ships’ wakes. Some kinds of mushrooms that grow on rotting wood emit a dim light called foxfire.


Fluorescence
Fluorescence is light that an object converts from one kind of electromagnetic energy of a different wavelenth. Some minerals, such as amber and calcite, will give off colorful visible light when they’re lit by ultraviolet light. Other minerals fluoresce during crystal formation.

Tips and Techniques

1. Set up a dim ambient lighting first, then add the luminescent effects.
2. Luminescent colors often gradate from one color to another along the spectrum.
3. Blue-green colors are most common in the ocean because they travel the farthest through water.
4. Luminescence is very dim and diffuse--it doesn't cast shadows.

8 comments:

Will said...

Mr. Gurney, I received Imaginative Realism for Christmas this year, and I am thrilled. I have nearly read all of it, and I am soaking in every bit of the amazing art education I am receiving through your powerhouse of a book. Thank you so much for the effort you have put into this, it really is a unique work. It has given me a 200% boost to think creatively, and given me a fresh mindset about illustration. Wishing you a blessed and creative 2010,
-Will Kelly

P.S. and thanks for signing it as well!

Markus B├╝hler said...

There is a highly spectacular cave in New Zealand, the Waitomo Cave, which is populated by the larvae of a a special fungus gnat (Arachnocampa luminosa). This larvae produce some kind of nest from silk on the ceiling of the cave, and also several dozen dropping threads which are covered with sticky drops. The larvae produce light with special organs of the abdomen to attract prey. When other insects come close to the light, they get entangled on the sticky threads. There are several species of Arachnocampa which also occur at some regions of Australia and Tasmania. Some of the species produce even sticky drops which are poisonous. I have never seen this insects in life, I know them only from TV and photos, but it looks really highly spectacular how this cretures simulate something like a starlight sky on the ceiling of a cave. I find this especially interesting, because there are very few animals in caves which are able to produce bioluminescence. The painting with the ferns and crystals looks really wonderful, it reminds me a bit to some descriptions of Jules Vernes novel "A Journey to the Center of the Earth". Sadly this novel is much too short, and it would have had much more potential, especially shortly before the end when the protagonists discover the prehistoric forest with the giant.

James Gurney said...

Hey, Will, thanks. I'm glad you're getting a lot out of it, and all my best wishes with your work.

Markus, I really appreciate your insightful comments about this topic and also about the Maiacetus a while back.

woos said...

Hey James!
Have you seen 'Avatar' yet? The visual effects are BEAUTIFUL. The forest plants glow at night with a luminescence much like your ferns. Such a pleasure to look at...

James Gurney said...

Woos, yes saw it. Mr. Cameron shows good taste in his borrowing. A lot of people have remarked on the influences, but I think the creative team broke a lot of new ground, too.

GooGoo Supreme said...

haha, so you did see avatar, he didnt borrow as blatently as lucas, but i think its clear to see he did borrow.

dinotopia's strength countinues to influence even now, thats very impressive, you must be very happy!

Roberto said...

I have done several ‘underwater’ murals that use fluorescent paints that glow under UV Lights (Black lights). The UV paints I used are called ‘WildFire’ and the tips you give are right-on as to their application. With the UV paints you need to fully render the image under normal ambient lights and then add the fluorescent paints under an Ultra-Violet light. You have to be careful because the UV paints can be quite garish under normal lighting, and a little goes a long way under ‘Black light’.
Markus’s post is very interesting. I’ve been told that most spiders’ eyes also fluoresce, that it’s easier to catch them at night. -RQ

MaureenHume said...

Wow! Really enjoying the post and the comments. I love words so it's interesting to learn the difference between 'glow words'.
By the way, I live in Tasmania and we do have heaps of caves filled with the amazing glowie things Markus Buhler mentions. We call them glow worms but I suspect that's a local term. In future I'll have to remember to call them bioluminescence glow worms. :o)
Maureen. www.thepizzagang.com