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## Tag: D65

### D65 n°5 half-way

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### second slice

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still 2 small triangles left, this “slice” contains a neutral almost at the middle of it, it’s a pity that the paper doesn’t remains flat…

### D65 n°4, four solutions, 2013

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A study for new graphic solutions.

### 3rd part of D65 n°4 (again)

working…..

Note: the orange color in particular isn’t really rendered by digital photo/computer screen

### another D65 n°4

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The previous post about D65 n°4 starting was false alert.

A lot of being human is about being stupid, and what happens then is failed works.

This is the ‘new’ or ‘real’ D65 n°4

### Stencils

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### D65 n°4, ‘primary-colors space,’ starts… :)

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First series of ‘primary colors:’

- Kremer Cadmium Red 2 + PR122 Sennelier

- Kremer Cadmium Red 2

- Kremer Cadmium Red 1

- Kremer Cadmium Red 1 + Kremer Zinc White  (various amounts)

Bottom right: Kremer Lamp Black + Kremer PB 15  (my new ‘super black’)

The square-grids are made using stencils & K. Lamp Black only, binder is Fish Glue.

Come back later…

### a messy update about ‘primary colors’

It’s been weeks since I started to ‘expand’ my collection of ‘primary colors.’ I have around 50 of them now, and it’s not finished.

If you wonder what I call a ‘primary color’ here’s a definition: in my system, it is a color that cannot be made from others. For example, If I superimpose opaque blue and white lines, I get a light blue that is less saturated than a blue made from the actual mixture of the 2 pigments. So that mixture becomes a ‘primary color. From this perspective, there’s an infinity of primaries, but still much much less than non-primaries.

A guy called Joshua Horowitz, (see:
http://web.mit.edu/joshuah/www/
) helped me solving the problem of defining primaries by programming a code that automatically ‘excludes’ non-primaries, among other things …

‘Primary’ colors: mixtures of organic/inorganic color pigments

a list of primaries

The little proto-software also allows a 3-D visualization of my ‘colorspace’ in CIE XYZ mode:

3D XYZ colorspace, every line intersection is a primary color

More important, the software automatically ‘solves’ a list of colors by giving max. 4 primaries for each target color, a great gain of time & simplicity…

I am now ready to explore the entire colorspace…

(temporary) gamut of my pigment-colorspace, and below:

‘genetic code’ of the picture above (Yxy colorimetric coordinates, sets of 4 primaries, necessary amounts for color matching)

### D65 n°1, details, 2011

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Very near “neutral grey”

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Equivalent optical average color samples

### D65 n°3, transparences / lampe / spectres, 2012

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Below, detail: desaturated daylight spectrum

### D65 #3 about to be finished

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View from the mezzanine in my studio.

### a new step: color with colors

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Average colors of the Blackbody radiation colors (from 3500°K to 9500°K) and the color of the background. 50% of the paper is covered by paint. (This actually equals a desaturated picture of these colors, i.e. the mixture of blackbody colors and white D65 light at equal power)

Doing optical greys with colors might become history in my work, I start doing colors with colors – let me say something about my color system here:

I use colors following “Grassmann laws,” that means that I measure the lights coming from my pigments to your eyes, and by varying the proportions of these pigments I change the average color of the light that comes to you.

That works exactly in the same way as you computer’s screen except that I have more primary colors and usually less light.

Here, I used 7 “primaries”: Ultramarine Blue greenish extra, Cobalt Turkish light, a Green mixture of the former and of the next, Cadmium Yellow light, Cadmium Red “Cinnaber” shade and Titanium White (see below)

The “primaries” of my system (didn’t use the Cobalt Pink here yet!)

To create a color, I will make the average of 4 of these primaries, so a “possible” color will always be located in a “pyramidal space” with a primary color at each peak.

If I add the Black  primary, the main pyramids will be:

ReGrBlu-White and ReGrBlu-Black. Around them you’ll have ReGrYe-Whi/Bk ;  GrBluTu-W/Bk ;  ReBluPink-W/Bk

Which makes a total of 8 pyramids that touch each other and define the gamut of my system! (see below)

8 pyramids = gamut of 8 colors

The best solution to get the amounts a, b, c, d of the colors A,B,C,D  required to get a given color M is to use matrix calculus:

with: a+b+c+d=1,

$\vec{M} = a.\vec{A} + b.\vec{B} + c.\vec{C} + d.\vec{D}$

the colors coordinates are in the CIE 1931 XYZ color space, so we create a square matrix with the color coordinates for each color, multiply by the solution, and equal it with the color we want:

$\begin{pmatrix} M_x \\ M_y \\ M_z \\ 1 \end{pmatrix} =
\begin{pmatrix} A_x & B_x & C_x & D_x \\ A_y & B_y & C_y & D_y \\ A_z & B_z & C_z & D_z \\ 1 & 1 & 1 & 1\end{pmatrix}
\times \begin{pmatrix} a \\ b \\ c \\ d \end{pmatrix}$

Then we solve this:

$\begin{pmatrix} a \\ b \\ c \\ d \end{pmatrix} = P \times \begin{pmatrix} M_x \\ M_y \\ M_z \\ 1 \end{pmatrix}$

with P being the inversion of our matrix:

$P = \begin{pmatrix} A_x & B_x & C_x & D_x \\ A_y & B_y & C_y & D_y \\ A_z & B_z & C_z & D_z \\ 1 & 1 & 1 & 1\end{pmatrix}^{-1}$

That’s it!

Thank you very much PA5CAL from this forum to have helped out!

http://forums.futura-sciences.com/physique/555235-aide-cherche-equation-proportions-de-couleurs-moyennees.html

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Today could be a great day for painting: Georges Seurat’s dream-project of a “scientific painting” advanced a little. I’m sure he would be (very) happy to see this. I wish I had the email of the painter’s paradise, I would send this to him and all his friends…

### D65 n°3 part II starts

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I’m gonna do a “lamp simulation” (a circular gradient with constant tint and varying brightness, based on the abstract model of a “perfect lamp,”) based on 11 colors: 3 times RGB with 3 levels of brightness (I dont enter into the detail of how I choosed them) and Black/White.