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Old 03-24-2017, 07:48 AM
tiago.dagostini tiago.dagostini is offline
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Re: Newton Vs Seurat (long but please read to end)

The eye does not distinguish the points. The eye do not even SEE everythign that you think you are seeing in any situation. The eye just samples averages of wavelenghts and wave intensities trough time while scanning a region. The optic nerve is not even capable of sending date from ALL the receptor cells at same time to the brain.

The brain interprets that sampling data and deduces what must be in front of you to generate such samples. If your samples cannot be explained by the brain by anything other than an object of color X then your brain will see color X.

When you see lots of small colored dots (that is exactly what you are doing now, because computer monitors are just lots of very small colored dots), you are just creating an illusion. You are reproducing a statistical field of samples that lead your brain to be deceived into seeing a specific shape or color.
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Old 03-24-2017, 03:59 PM
theBongolian theBongolian is online now
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Re: Newton Vs Seurat (long but please read to end)

so perhaps the reason the yellow and blue dots on a Seurat painting appear green instead of cyan is because the dots are too big. If the dots were to gradually decrease in size they would appear to fade from green to cyan?
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Old 03-25-2017, 05:07 AM
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Gigalot Gigalot is offline
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Re: Newton Vs Seurat (long but please read to end)

Quote:
Originally Posted by theBongolian
so perhaps the reason the yellow and blue dots on a Seurat painting appear green instead of cyan is because the dots are too big. If the dots were to gradually decrease in size they would appear to fade from green to cyan?
Seurat paintings appear gray, not green. His paintings are very DULL and well demonstrate dull result of additive average mixing. In the other hand, another Pointillist Alfred Sisley was sure that Seurat method gives outstanding dull and boring colors. He tried to use a lot of bright Magenta color in his paintings and a lot of Cyan. Bright Magenta; Cyan and Yellow colors he applied in large rectangular strokes. In his paintings, CMY strategy gives much vivid colors while large paint strokes reduce optical mixing dullness. Matisse also started with large and very saturated dot painting but after a short time dropped this idea. He called Pointilism as "Old province aunt's dictatorship"! (My own opinion about Pointilism artistic style)

Last edited by Gigalot : 03-25-2017 at 05:14 AM.
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Old 03-25-2017, 07:16 AM
davidbriggs davidbriggs is offline
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Re: Newton Vs Seurat (long but please read to end)

Quote:
Originally Posted by theBongolian
BUT it would seem in the case of a Seurat painting - blue and yellow dots too small for the eye to separately distinguish at view distance should appear as grey - due to additivive average mixing. However they appear as green albeit a low chroma green but green never-the-less.

Can you show us one Seurat painting where he attempted to make green from blue and yellow dots (let alone suceeded!)?
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Old 03-25-2017, 09:09 AM
theBongolian theBongolian is online now
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Re: Newton Vs Seurat (long but please read to end)

--busted-- I was using Seurat as a hypothetical. But I took a look - online - at Seurat and it appears he used a lot of yellow, blue, and green dots in the same field. The yellow and blue dots ARE next to each other. So was his intent to create a second shade of green? Don't know. Did he succeed? No.

So let me see if I have this right. Tiny yellow and blue dots next to each other make gray. Tiny yellow and blue transparent dots placed on top of each other make green. A spinning newton's disc with painted rainbow colors, or r,g,b will only get to grey due additive average mixing.

Could a spinning newton's disc with transparent rainbow sectors achieve white - or clear?? Or would it just be a lighter shade of gray since there would be still be some additive average mixing?

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Old 03-26-2017, 04:23 PM
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Re: Newton Vs Seurat (long but please read to end)

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Could I be wrong? Sure. But someone please explain to me why Seurat's Dots produce one outcome, and Newton's Disc (supposedly) another. Both used PIGMENT colors not individually perceivable to the eye - yet they (supposedly) got different results. So what's going on??

Seurat's Dots were doomed to failure from the outset. The reason is that they are colors of pigments, rather than colors of light. Another reason is that in order for the painted result to appear as expected, resulting colors do in a spinning disc, they simply MUST be placed side-by-side, and NOT on top of one another.

However, even with pigments, a spinning disc of the 3 basic colors of light, Red, Green, and Blue can be made to function to create White, by the additive behavior of color, provided several conditions are met.

Those conditions are as follows:

First, the light source under which such a disc is viewed should be an intense, nearly full-spectrum light source, rather than just some incandescent lightbulb burning in the corner of your living room, or studio.

Second, the pigment colors that you select to be representative of "Red", "Green", and "Blue" as sections of the disc need to be as pure, and as "scientific" (realizing that some artists on this site dislike it when I use the term, "scientific") as possible. In other words, one cannot not merely grab some color that is labeled "Red" on its tube, and expect it to function as well as true, scientific Red, for this purpose. It must be true, RED, and as close to the Red spoke of the color wheel as possible, as well as being as near the outer ring as possible, as well.

The same criterion goes for the Green, and Blue colors on this wheel, as well.

This sort of selection of Red, Green, and Blue is not easy when dealing with pigments, but it is absolutely necessary if you wish your spinning disc to actually appear as "White", or "near-White" when viewed under a full-spectrum illumination.

I can guarantee that such a wheel, composed of pigments, will truly work to the extent that when spun, the Red, Green, and Blue sections of the spinning disc will actually appear White. And, when the Blue section is covered with Black, it will appear Yellow. When the Green section is covered with Black the color will appear to be Magenta, and when the Red section is covered with Black, the color will be Cyan.

I know this works, because I have seen such a spinning disc, made of Red, Green, and Blue pigments, and the results were as should be expected.

The problem with Seurat's approach is that he was not using pure Red, Green, and Blue pigments--instead, probably just grabbing any ol' paint labelled "Red", "Green", or "Blue" for his true, Red, Green, Blue primary colors of light, as well as piling some on top of each other rather than carefully placing them side-by-side. Such a sketchy approach surely won't function well, and will undoubtedly yield such grayed colors as were forthcoming in his paintings.

It is nice to experiment with the "basics of color" in a painting, but when you do, it is also imperative that you understand the true science of the behavior of color, and what real colors are required to achieve the expected results.

Using any ol' Red, any ol' Green, and any ol' Blue simply won't cut it, and Seurat seems to have done just that. He seems to have latched onto one, basic principle of color, but failed to have gained the knowledge of several other ones that may have led to a bit better results.

For what it may be worth, the RGB spinning disc that I witnessed that was so extraordinarily successful in creating White, as well as Cyan, Magenta, and Yellow was made up of colored poster board for which the demonstrator had shopped for an enormously long time. He had gone through lots of trial-and-error attempts with various colors, and finally had settled on some colors that were (if I recall correctly) in the form of what they called, "Day-Glo" colors--extremely pure, and bright. This spinning disc was a real jaw-dropper, and it turned many skeptics into believers of the true behavior of color, once viewed by them.

Oh, .....and just a a helpful bit of insight regarding this spinning disc of additive, Red, Green, and Blue colors, the true Red is a color that MOST artists would call "Orange".
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Last edited by WFMartin : 03-26-2017 at 04:42 PM.
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Old 03-26-2017, 08:12 PM
tiago.dagostini tiago.dagostini is offline
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Re: Newton Vs Seurat (long but please read to end)

Quote:
Originally Posted by theBongolian
so perhaps the reason the yellow and blue dots on a Seurat painting appear green instead of cyan is because the dots are too big. If the dots were to gradually decrease in size they would appear to fade from green to cyan?


if they emited light like monitor pixels do they would be able to deceive your eyes into seeing whatever color you want.

Whern you try to physically reflect them you find a barrier that there is not enogu energy reflected from each point to activate yourperception.
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Old 03-26-2017, 08:58 PM
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Re: Newton Vs Seurat (long but please read to end)

Quote:
so perhaps the reason the yellow and blue dots on a Seurat painting appear green instead of cyan is because the dots are too big. If the dots were to gradually decrease in size they would appear to fade from green to cyan?

In a perfect world, with colors of light, instead of pigments, the colors Blue, and Green would appear Cyan to the eye of the viewer of this mixture, not Yellow and Blue. Yellow and Blue should appear gray, because they are complements.
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Old 03-28-2017, 02:39 AM
SamL SamL is offline
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Newton Vs Seurat (long but please read to end)

Quote:
Originally Posted by theBongolian
So let me see if I have this right. Tiny yellow and blue dots next to each other make gray. [/IMG]
I think you are right.

I created a bitmap image file. It consists of repeated patterns of the following checkerboard of yellow and blue dots. I made the yellow dots and the blue dots have the same lightness, so when the dots become small, the image will look smooth. For any two adjacent dots, the sums of RGB are (255, 255, 255). For the yellow dot, RGB=(137, 137, 0). For the blue dot, RGB=(118, 118, 255).



When the dots become small, does the image appear to be gray?



Wetcanvas does not accept bitmap image files. So I had to convert them to JPG files and upload them to Wetcanvas. The JPG files are approximations of the original bitmap files.

Last edited by SamL : 03-28-2017 at 03:30 AM.
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Old 03-28-2017, 02:45 PM
theBongolian theBongolian is online now
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Re: Newton Vs Seurat (long but please read to end)

Thanks Sam! Nothing like hard evidence to make a point.
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Old 03-28-2017, 07:53 PM
davidbriggs davidbriggs is offline
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Re: Newton Vs Seurat (long but please read to end)

Quote:
Originally Posted by theBongolian
--busted-- I was using Seurat as a hypothetical. But I took a look - online - at Seurat and it appears he used a lot of yellow, blue, and green dots in the same field. The yellow and blue dots ARE next to each other. So was his intent to create a second shade of green? Don't know. Did he succeed? No.

There's no reason to think Seurat ever tried to create green from yellow and blue dots. Firstly, his rationale was to break colours down to their spectral components, and green is a spectral colour. Secondly, he would have known from his study of Ogden Rood that in additive and additive-averaging mixing yellow and blue are complementary.

There's a persistent myth that Seurat thought he could get brighter and/or more intense colours by pointillism than could be obtained by physical mixing. This idea is based on a careless misreading of experiments by Ogden Rood, who compared physical mixtures with spinning-disc mixtures and showed that the latter always had greater "luminosity", meaning only that they were lighter in greyscale value than physical mixtures of the same paints.

From a very early stage critics made the mistake of thinking Rood was saying that you could get more intense colours by optical mixing than by physical mixing, but it's highly unlikely that Seurat made this error. If you look at the brightest green things like grass in his paintings they are always painted very simply, mainly with dots of green paint. Seurat used pointillist colour mixing most extensively in the greyer areas of his paintings, in order to paint them with touches of bright colours, and thus to create an effect of what Rood called "lustre" when viewed at the intended distance.

The "yellow" dots in your detail appear to be the orange-yellow ("solar orange") that Seurat used in areas lit by direct or reflected sunlight to add a colour component in the direction of the colour bias of the sunlight.

Quote:
Originally Posted by theBongolian
Could a spinning newton's disc with transparent rainbow sectors achieve white - or clear?? Or would it just be a lighter shade of gray since there would be still be some additive average mixing?

The answer depends on how you view the spinning disc. Against a white background the transparent spinning disc would look grey, but light projected through it alone would look white.

Last edited by davidbriggs : 03-28-2017 at 08:00 PM.
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