Øyvind Kolås    pippin@gimp·org twitter liberapay bitcoin patreon  

Spectral ink simulator

Spectral ordered ink/paint soft proofing and separation engine. In the upper left corner we see the substrate, followed by subsequent layers of colorant in the configuration.

Most of the colors references by name are internal presets for spectral measurements - wheras entries with 'rgb ? ? ?' entries indicate synthesized spectrums.

original
black.png
# virtual printer configured with one ink, black
illuminant=D65
substrate=white
ink1=black
 
bw-on-green.png
illuminant=D65

substrate=green   # green background

ink1=black
ink2=white
ink2.black=white

chalkandcoal.png
# simulating charchoal and chalk

illuminant=D65
substrate=rgb 1 0.6 0.6
ink1=black
ink2=white
ink2.black=white
cmyk1.png
# simulation using reasonable data;
# gives a quite small color gamut

illuminant=D65
substrate=white
ink1=cyan
ink2=magenta
ink3=yellow
ink4=black
inklimit=2.5
cmyk2.png
# same as previous ink configuration
# allowing only 150% ink on an pixel.

illuminant=D65
substrate=white
ink1=cyan
ink2=magenta
ink3=yellow
ink4=black
inklimit=2.2
cmyk3.png
# white paint + CMY print on black
# 

illuminant=D65
substrate=black
ink1=white
ink1.black=white
ink2=cyan
ink2.black=cyan
ink3=magenta
ink3.black=magenta
ink4=yellow
ink4.black=yellow
inklimit=3.0
cmyk4.png
# using simulated "ideal" inks - giving unnatural
# gamut for CMYK

illuminant=D65
substrate=white
ink1=rgb 0 1 1
ink2=rgb 1 0 1
ink3=rgb 1 1 0 
ink4=rgb 0 0 0

cmyk5.png

# CMYK printing on yellow paper

illuminant=D65
substrate=rgb 1 0.6 0.6
ink1=cyan
ink2=magenta
ink3=yellow
ink4=black
greenblack.png
# duo-tone printing of green + black on white

illuminant=D65
substrate=white
ink1=black
ink2=green

redblue.png
# duo tone printing with red / blue

illuminant=D65
substrate=white
ink1=red  
ink2=blue 

redgreen.png
# duo tone printing with red and green

illuminant=D65
substrate=white
ink1=red  
ink2=green

rgb.png
# printing with red/green/blue inks -
# works quite well for colors in this photo

illuminant=D65
substrate=white
ink1=red
ink2=green
ink3=blue

whiteandgreenonblack.png
# duotone print on top of black

illuminant=D65
substrate=black
ink1=white
ink1.black=white
ink2=green

debugwidth=48
whiteandredonblack.png
illuminant=D65
substrate=black
ink1=white
ink1.black=white
ink2=red

debugwidth=48

These images represents recent advances in these experiments - the current working incarnation of the software is currently not publicly available. /pippin.