Posterizations - Sandy

I was a Professional Photographer from around 1968 to 1975. This is the detailed discussion of How I Made Them in a darkroom over thirty-five years ago. (Maybe I'll do another page one day on how I do it digitally today.)

sandyA (CMY)

This is a scanned image of a dye transfer print made in 1974. It is the result of ten hours of work in the darkroom, although only about two hours was actually spent in the dark. The important thing to note is that there are eight colors present … progressing from the shadows to the highlights, they are Black, Red, Yellow, Green, Cyan, Blue, Magenta, and White.

Black & white original (256 shades)

Black & white posterization (8 shades)

This is the original image … a black & white 35mm negative transferred to a Kodak® PhotoCD at 2,048x3072x16.8M colors. <whew!> The model's name was Sandy, and we did this in a public park in Genesee Valley (Rochester, NY) before the rush hour traffic made public nudity a Risky Business. This early morning shoot, a bare half-hour after sunrise, explains the long shadows.

The image on the left has 256 shades of gray (even though the average human eye can only distinguish 64 shades), while the one on the right has been posterized to eight shades of gray … the trick is to replace each of the eight shades with a color.

Don't be alarmed, but the eight colors are derived from only three colors of dye … Cyan, Magenta, and Yellow. That means we only need three "images" to be printed.

The dye transfer process uses sheets of film called matrices that have a layer of gelatin whose thickness is proportional to its exposure to light. Developing matrices includes a tanning step, and the unexposed emulsion is washed off. Making the matrices is the middle step … it takes about two hours, but there's another four hours work required to reach that point.

Once the three matrices are made, there are six possible combinations of dying them in the three colors. That's why the image in the upper left corner is called the "A" variation. Clockwise from the upper right corner are matrix #1 (C), matrix #2 (M), and matrix #3 (Y)

Var. A (CMY)	Matrix #1 - Cyan	Matrix #2 - Magenta	Matrix #3 - Yellow
	Matrices #2 & #3 Magenta + Yellow = Red	Matrices #1 & #3 Cyan + Yellow = Green	Matrices #1 & #2 Cyan + Magenta = Blue

Deriving these matrices from the original continuous-tone (analog) image of Sandy required a half dozen exposure/development cycles, mostly performed in the dark.

2009-09-04: Well, I finally got a round TUIT, so here is How the Magic Works …

Step One: From the original black and white negative, make 7 different positive images on KODALITH high-contrast film. These images vary in exposure time, highlighting from the deepest shadows to the brightest highlights. The times varied with the contrast of the image, so I usually made 10-12 exposures and chose the 7 best.

This step is usually performed using an enlarger, but all of the subsequent steps require careful image registration and use contact printing.

Original negative image	Positive #1	Positive #2	Positive #3
Positive #4	Positive #5	Positive #6	Positive #7

Step Two: Make seven negative images by contact printing the positives on KODALITH. (From this point on, all high-contrast exposures are identical.) Note that N4 with be used to make Matrix #3 (default Yellow)

Positive image	Negative #1	Negative #2	Negative #3
Negative #4 (Mat#3 neg)	Negative #5	Negative #6	Negative #7

Step Three: Register P3 with N6 and contact print to make N8.

P3 + N6

N8 (P3 + N6)

Then Register P5 with N7 and contact print to make N9.

P5 + N7

N9 (P5 + N7)

Step Four: Register N8 with P1 and contact print to make N10. This will be used to make Matrix #1 (default Cyan) by contact printing.

N8 + P1

N10 (Mat#1 neg)

Then register N9 with P2 and contact print to make N11. This will be used to make Matrix #2 (default Magenta) by contact printing.

N9 + P2

N11 (Mat#2 neg)

Now that you have the three master negatives, you can make Matrix #1 from N10, Matrix #2 from N11, and Matrix #3 from N4 by contact printing. Then you can make the six Variations by using the six different matrix/dye combinations.

Matrix #1

Matrix #2

Matrix #3

From this point on, everything is done in normal room light. Because of the time required for the matrices to absorb dye, and for the dye to transfer from the matrices to the paper is a cycle of about 20 minutes for each print, and the registration/print system only allows for one print at a time. and the matrices have to be thoughroughly cleaned before being used with a diffrent color of dye, so figure a good three hours to make one set of six variations.

Matrix #1 - Cyan	Matrix #2 - Magenta	Matrix #3 - Yellow	Variation A - CMY
Matrix #1 - Magenta	Matrix #2 - Yellow	Matrix #3 - Cyan	Variation B - MYC
Matrix #1 - Yellow	Matrix #2 - Cyan	Matrix #3 - Magenta	Variation C - YCM
Matrix #1 - Yellow	Matrix #2 - Magenta	Matrix #3 - Cyan	Variation D - YMC
Matrix #1 - Magenta	Matrix #2 - Cyan	Matrix #3 - Yellow	Variation E - MCY
Matrix #1 - Cyan	Matrix #2 - Yellow	Matrix #3 - Magenta	Variation F - CYM

Yellow Brick Road: The path to the Mother of all Virtual Realities.

• Dennette's Homeboy Page: This is where it begins
  • Dream Walk: The Electronic Journal of DAHarrod
    • Dennette's Photography Career: Pictures of ecdysiasts
      • Gallery of Posterizations: The parent of this child.
        • Posterizations - sandy: index.htm: YOU ARE HERE.

Last update: 2009-09-06 by <Dennette@WiZ-WORX.com>
<Who is this Dennette person?>