Science

[Blackheart]

Color filters are used for most printers. Scanners have them also, but they take more tweaking to get right.

[Mercutio]

Originally Posted by Nurvingiel

*hijacks thread*

I just learned something cool about colour. When you look at traditional art like a painting, you are looking at reflected light. The primary colours are red, blue, and yellow.

When you look at a computer screen, the colours you see are projected light. All colours are made up of red, blue, and green. Pretty rad huh? That's why when you scan a colour image, the colours are slightly different.

We just studied this in physics class. They aren't quite the same red and blue:

I illustrate with smileys.

Primary light colors/secondary pigment colors = red ( ), green (, sort of), and blue (, sort of)

Primary pigment colors/secondary light colors = magenta (), yellow (), and cyan ( )

[Earniel]

Originally Posted by Nurvingiel

*hijacks thread*

I just learned something cool about colour. When you look at traditional art like a painting, you are looking at reflected light. The primary colours are red, blue, and yellow.

When you look at a computer screen, the colours you see are projected light. All colours are made up of red, blue, and green. Pretty rad huh? That's why when you scan a colour image, the colours are slightly different.

And yet, when you have your digital photos printed, they look the same. The photo lab must have some genius software.

Interesting.

Do you reckon that this explains why my scanner can't handle certain tints of violet and why green is often the last colour in my ink cartridge?

[Lizra]

Here is a bit (from "Painter's Keys" Robert Genn newsletter) about the cyan, magenta, and yellow....

Maxfield Parrish



About a hundred years ago when three-colour "process" printing was being perfected, some artists, particularly illustrators, wondered if they might paint like that too. One of them was the American Maxfield Parrish. Marveling at the richness derived from a small range of printer's inks, Parrish invented a painting system that used only cyan, magenta, yellow and black. Instead of photographically separating the four as in the printing process, he methodically assembled them on a bright white (generally stretched paper) ground. Transparent oil glazes were alternately isolated with varnish. The result was luminosity--and a unique style.

Fortunately, there are a few of Parrish's half-finished paintings around. In Dreaming (1928), there was originally a nude woman seated by a large tree. After publication, Parrish decided to remove the girl and change various elements. He never completed the job. This painting clearly demonstrates his technique.

Using a small group of models, including himself, Parrish, together with photographic aids, contrived his subjects into idealized, often flattened compositions. Faces in profile or facing the viewer come out better than three-quarter views. Monochromatic and analogous colour schemes intersperse with magnificent gradations--often in the legendary "Parrish Blue." The overly golden aspect of some paintings, however, is the outcome of maturing varnish. His backgrounds are the stuff that dreams are made of. When you let your eyes cruise the originals (they also show well on the Internet) you can't help but think of some of the digital art that is being done these days. Parrish also noted a benefit of his slow-drying oil glaze process--simultaneity. Racks of paintings were on the go at once.

Maxfield Parrish (1870-1966) lived most of his life in an ivory-tower fantasy in Cornish, New Hampshire. A 'prop shop' nearby was used to build his complex reference. Apart from doing book and magazine illustration, he made a comfortable living from paintings that were often made into prints and posters. Yesterday, while cruising the local flea market, I met up with a miraculous, androgynous girl, naked in a fairytale world.

Best regards,

Robert

PS: "The hard part is how to plan a picture so as to give to others what has happened to you. To render in paint an experience, to suggest the sense of light and color, of air and space." (Maxfield Parrish)

Esoterica: Parrish was a creative inventor who took pains to get things right. I get the impression he was a self-effacing, practical, workaday person, very much in touch and struggling with his shortcomings. Industrious to the end--he painted until age 90--"fine art" was a bit of a mystery to him. "There are countless artists whose shoes I am not worthy to polish--whose prints would not pay the printer," he said, "the question of judgment is a puzzling one."

[brownjenkins]

I always liked Maxfield Parrish's work and use to have a few of his posters in in my old apartments. A very unique style. Or at least to my untrained eye.

[Lizra]

Now you know part of the style! Ah........Luminosity!

[trolls' bane]

Interesting! CMYK?

Originally Posted by Blackheart

Isn't it more like interstellar dust?

One would assume that samples that far away from a star would have been affected by the environment at least to some degree....

What environment?

[trolls' bane]

Odd. I KNOW I've posted here since March... Oh well...

I just read an article on a theory by an Isreali physicist, who was studying the galactic rotation curves that have so baffled astronomers* for decades. Though dark matter seems to be an appropriate theory that fits the results, MOND (which stand for Modified Newtonian Dynamics) also fits the results without requiring something that, to date, has failed all attempts to observe.

I'm not sure how it applies to the rest of the universe, since many people base the evoloution of the early universe on dark matter, and it would have to encompass all of the areas dark matter does. I'm going to look into the theory and see what comes up.


*In case your not familiar with what this is, think of a spiral galaxy. The core of the galaxy, a central "bulge" in an otherwise flat disc of stars, is the densest part of the galaxy, containing older stars, and contains the most mass. Therefore, from simple Newtonian mechanics, this means that the further from the core you get, the slower everything rotates because of the significantly decreasing gravitational attraction fron the core. So therefore, the line on a graph of speed compared to the distance from the core should begin to go down the further from the core you get. However, the curve doesn't go down: it flattens out. And the way it does allows astronomers (still using mainly Newtonian mechanics) to predict the amount of mass that would be required to cause such results. In answer, they proposed dark matter, a type of matter that does not emit or reflect light, making up over eighty percent of the universe's total mass.

[Jonathan]

That is interesting stuff. I've never heard of Modified Newtonian Dynamics. If you dig into the theory, you should post about it here.

[Blackheart]

Originally Posted by trolls' bane

Interesting! CMYK?

What environment?

*raps the lectern*

Where does interstellar dust come from?

Dust, not hydrogen. Hydrogen coalesced from subatomic particles when the initial firestorm cooled off...

It's interesting to think that there are still actual hydrogen molecues out there that haven't collided with any other bit of matter since the begining of matter in the universe...

Any other heavier element had to have been compacted in a gravity field... i.e dust...

Gravity field means that it had to have been in proximity to stellar phenomena at some point...

[Lizra]

There! Got that TB?

[Blackheart]

Originally Posted by trolls' bane

MOND (which stand for Modified Newtonian Dynamics) also fits the results without requiring something that, to date, has failed all attempts to observe.

I'm familar with MOND, the central tennant being that gravity has a "long range" effect on acceleration that differes from it's short range effects.

While interesting, there is no mechanism to explain this long range effect...

Dark matter has it's problems, and it's not my favorite solution either, but without a real mechanism to explain the difference in gravitic attraction, MOND is likely to remain a stepchild theory...

[Jonathan]

Originally Posted by Blackheart

While interesting, there is no mechanism to explain this long range effect...

There's no well-substantiated explanation for how "normal" gravity (the short range gravity that we experience) works either though. Gravity is a mystery.

[Blackheart]

There is a mechanism for explaining gravity over short range ( say a couple of light-years or so) ....

If I recall it's called "curvature of space-time" ...

But the issue with the idea of gravity having a DIFFERENT effect at long range (hundreds or thousands of light years) is that the curve in space would have to be different at long ranges.

No one has suggested a mechanism for this.

It could be as simple as providing a mathmatical explination for why spacetime is a "firm" material, meaning that gravatic effects on the fabric of space time in one area have a corresponding "ripple" effect at larger distances.. Like a bowling ball in the middle of a bowl of pudding causes a valley... but it also displaces material to cause hills elsewhere...

but no one has even provided a model, that I am aware of....

No we don't know the underlying mechanism for gravatic attraction; i.e. WHY it causes space to curve (if that is indeed what it does) but space curvature is a mechanism to explain observed gravitic effects.

My personal favorite is the idea of the massive charge contained within matter (a much stronger force than gravity or magnitism) exherts such an effect on virtual particles, that it causes them to align their "possibilities" along the same lines of forces as the strong attractive forces in the matter, creating a curve in space time.

Though I freely admit that no one has a sensible mechanism as to why changing the alignment of virtual particles would change the curvature of space unless you buy into the model that empty space itself is composed of virtual particles...

In essence the only thing that keeps space from collapsing is the energy contained within the virtual particles.. the possibility that something might be there... Which is a really interesting idea of "empty" space...

[Jonathan]

Originally Posted by Blackheart

There is a mechanism for explaining gravity over short range ( say a couple of light-years or so) ....

What I meant was that the mechanisms behind gravity is not as well understood as electromagnetism, the strong nuclear or the weak force.

[edit] which is kinda funny since Newton "discovered" gravity long before the other forces were described.

[Blackheart]

WHen it comes to the fundamentals, magnetism and EM aren't well understood either. But there are models for how they work. i.e. nuclear force and attraction/repulsion

With MOND, there is no model for how or why gravity changes at long range, just an observation that it does...

Well yes, it does. That's one of the reasons that dark matter was proposed in the first place. But just changing the formula to factor in the long range forces doesn't propose a mechanism for WHY gravity acts that way at extreme distances....

UNTIL someone proposes a mechanism that can be tested, MOND will remain a curiousity. The formulas work, and work well, but it doesn't explain anything. It does pose interesting questions, so it is of value, but it's still a curiousity in search of a mechanism...

[Earniel]

Lucy's baby found in Ethiopia

A whole skull! The archaeologists must be having a field day. Quite an exciting find.

[Gwaimir Windgem]

Now, how could they know it's Lucy's baby? Tha'z jes' silly.

[Earniel]

Possible oldest human ritual found

And a good 30.000 years earlier than originally thought. Sounds very interesting.

[brownjenkins]

Cool story!