Tone Reproduction
Background
Tone Reproduction curves show the relationship between reflectance
and the ink density. The reflectance is measured by a Colorimeter calibrated
with a D65 light source. The values of the reflectance are between 0 and
1. Adjusting the values as such will later prove to be useful. The ink
density is determined by an error_diffusion halftoning scheme. The density
is represented by values between 0 and 1. Density is the percentage of
ink (cyan, magenta, or yellow) applied to the printer paper.
By representing ink density and reflectance by numbers between 0 and
1, we are able to determine the relationship between the halftoning scheme
and the printer output. In the tone reproduction curves shown below, we
have fitted curves to data that relates measured reflectance and density.
By taking the inverse of these fitted curves, we create a function that
adequately relates the amount of ink applied to the
paper to the respective halftoning scheme.
Cyan
Tone Reproduction Curve
Magenta
Tone Reproduction Curve
Yellow
Tone Reproduction Curve
Results
To see the effects of the tone_reproduction_curve on the data, click
here.
To see the original data, click here.
The picture of the figure shown after altering the printer calibrated
data is significantly different from that of the original file. The halftone_specific
image result is unlike the original printer calibrated image because it's
values are dependent upon the halftone scheme applied. For a demo of the
printout of the image, please see Angela Hodge and Joy Ku.
When the image is printed out on the ise755cm printer through the Error
Diffusion halftoning filter, the majority of the colors: blue, black, green,
red, cyan, and white, are far superior to the equivalent colors produced
by the image printed without having a halftoning scheme applied.
