Wednesday, April 11, 2012

The Curves for the Corrected Print

The curve at the bottom is a correction curve made in Photoshop. It compensates for the deviations from the "K" or blackness on the palladium print as compared to ideal stepwedge values.

Then next curve up shows the ink distributions in the printer program QTR after the correction. In fact, 8 inks are used, but most copy other curves. This is quite smooth and produces enough ink to provide a real spectrum of linearized tones via the ultra-violet exposure.

The corrections are made by using a scanner as a densinometer to determine the actual "K" readings in the palladium print.

These instructions are fed to the QTR program via a *.qdif file which is an ASCII file. This is the file which produced the corrected curve:

PRINTER=Quad4900
CURVE_NAME=NewSeries16wTwk1
GRAPH_CURVE=YES
N_OF_INKS=8
DEFAULT_INK_LIMIT=100
BOOST_K=28
LIMIT_K=20
LIMIT_C=20
LIMIT_M=20
LIMIT_Y=20
LIMIT_LC=24
LIMIT_LM=24
LIMIT_LK=24
LIMIT_LLK=0
N_OF_GRAY_PARTS=2
GRAY_INK_1=K
GRAY_VAL_1=100
GRAY_INK_2=LK
GRAY_VAL_2=30
GRAY_HIGHLIGHT=0
GRAY_SHADOW=0
GRAY_OVERLAP=
GRAY_GAMMA=1
GRAY_CURVE=D:\Photography\NewSeries1pt0Twk1.acv
N_OF_TONER_PARTS=0
TONER_HIGHLIGHT=10
TONER_SHADOW=10
TONER_GAMMA=1
TONER_CURVE=
N_OF_TONER_2_PARTS=0
TONER_2_HIGHLIGHT=10
TONER_2_SHADOW=10
TONER_2_GAMMA=1
TONER_2_CURVE=
N_OF_UNUSED=0
COPY_CURVE_C=K
COPY_CURVE_M=K
COPY_CURVE_Y=K
COPY_CURVE_LC=LK
COPY_CURVE_LM=LK
COPY_CURVE_LLK=LK

No comments:

Post a Comment