High density ink-jet printing on a transparency

A method of printing a high density image on a transparent medium, comprising:

• using a first function that calculates an expected optical density as a function of pixel value, calculating a plurality of expected optical densities over a plurality of pixel values, the first function representing a substantially linear relationship between pixel value and optical density as substantially perceived by a human eye, the calculations performed using one or more computer processors;
• measuring a plurality of optical densities of a test image printed on an inkjet printer, each optical density being associated with a pixel value;
• interpolating a second function that describes the relationship between pixel value and optical density based on the measured plurality of optical densities;
• and
• based on the first and second functions, calculating a transfer function that maps input pixels to output pixels such that the maximum input pixel value produces an optical density on the transparent medium of at least 2.5.

A machine readable medium that stores instructions which when performed by a machine, causes the machine to perform operations, comprising:

• converting input pixel values into output ink values using a lookup table, wherein the lookup table comprises:
• input pixel value 255, black output value about 251, cyan magenta and yellow output value about 102;
• input pixel value 242, black output value about 234, cyan magenta and yellow output value about 84;
• input pixel value 230, black output value about 220, cyan magenta and yellow output value about 72;
• input pixel value 217, black output value about 206, cyan magenta and yellow output value about 64;
• input pixel value 204, black output value about 193, cyan magenta and yellow output value about 57;
• input pixel value 191, black output value about 181, cyan magenta and yellow output value about 51;
• input pixel value 179, black output value about 170, cyan magenta and yellow output value about 45;
• input pixel value 166, black output value about 159, cyan magenta and yellow output value about 41;
• input pixel value 153, black output value about 148, cyan magenta and yellow output value about 36;
• input pixel value 140, black output value about 137, cyan magenta and yellow output value about 32;
• input pixel value 128, black output value about 127, cyan magenta and yellow output value about 29;
• input pixel value 115, black output value about 117, cyan magenta and yellow output value about 25;
• input pixel value 102, black output value about 106, cyan magenta and yellow output value about 22;
• input pixel value 89, black output value about 96, cyan magenta and yellow output value about 19;
• input pixel value 77, black output value about 85, cyan magenta and yellow output value about 16;
• input pixel value 64, black output value about 74, cyan magenta and yellow output value about 13;
• input pixel value 51, black output value about 62, cyan magenta and yellow output value about 10;
• input pixel value 38, black output value about 50, cyan magenta and yellow output value about 7;
• input pixel value 26, black output value about 36, cyan magenta and yellow output value about 5;
• input pixel value 13, black output value about 20, cyan magenta and yellow output value about 3;
• and
• input pixel value 0, black output value about 0, cyan magenta and yellow output value about 0.

A method for printing an image, comprising:

• converting input pixel values of an input image into output ink values using a lookup table, wherein the lookup table comprises:
• input pixel value 255, black output value about 251, cyan magenta and yellow output value about 102;
• input pixel value 242, black output value about 234, cyan magenta and yellow output value about 84;
• input pixel value 230, black output value about 220, cyan magenta and yellow output value about 72;
• input pixel value 217, black output value about 206, cyan magenta and yellow output value about 64;
• input pixel value 204, black output value about 193, cyan magenta and yellow output value about 57;
• input pixel value 191, black output value about 181, cyan magenta and yellow output value about 51;
• input pixel value 179, black output value about 170, cyan magenta and yellow output value about 45;
• input pixel value 166, black output value about 159, cyan magenta and yellow output value about 41;
• input pixel value 153, black output value about 148, cyan magenta and yellow output value about 36;
• input pixel value 140, black output value about 137, cyan magenta and yellow output value about 32;
• input pixel value 128, black output value about 127, cyan magenta and yellow output value about 29;
• input pixel value 115, black output value about 117, cyan magenta and yellow output value about 25;
• input pixel value 102, black output value about 106, cyan magenta and yellow output value about 22;
• input pixel value 89, black output value about 96, cyan magenta and yellow output value about 19;
• input pixel value 77, black output value about 85, cyan magenta and yellow output value about 16;
• input pixel value 64, black output value about 74, cyan magenta and yellow output value about 13;
• input pixel value 51, black output value about 62, cyan magenta and yellow output value about 10;
• input pixel value 38, black output value about 50, cyan magenta and yellow output value about 7;
• input pixel value 26, black output value about 36, cyan magenta and yellow output value about 5;
• input pixel value 13, black output value about 20, cyan magenta and yellow output value about 3;
• and
• input pixel value 0, black output value about 0, cyan magenta and yellow output value about 0.