I have been trying for the past 5 months to put together a process of producing digital negatives for P&P printing. I live in rural France, so no chance of a workshop for the moment.
I bought Ron's pdf book and started to use his method of using the epson Driver and PS curves to produce a negative, but just could not produce a linearized curve and after 3 months decided to change to the quad RIP system. THis system I find a little confusing as I am never sure (apart from the Limits) what exactly each function does as the smallest amount of change in the txt files appears to have a global affect.
I have eventually got a txt file which gets a little close, but I am not able to separate the 5 to 15% highlights and the shadows do not go beyond 95%. I would be grateful for all suggestions.....
System mac OSX10.11.6
printer epson 3880
paper Arches platin
Coating, normal mixture (bostick)
Home made lightbox, with exposure time of 15 min verified.
Text file that gets close
PRINTER=Quad3880
CURVE_NAME=RON READer colour
GRAPH_CURVE=YES
N_OF_INKS=8
DEFAULT_INK_LIMIT=36
BOOST_K=0
LIMIT_K=
LIMIT_C=32
LIMIT_M=32
LIMIT_Y=24
LIMIT_LC=24
LIMIT_LM=32
LIMIT_LK=50
LIMIT_LLK=100
N_OF_GRAY_PARTS=3
GRAY_INK_1=K
GRAY_VAL_1=100
GRAY_INK_2=LK
GRAY_VAL_2=35
GRAY_INK_3=LLK
GRAY_VAL_3=15
GRAY_HIGHLIGHT=0
GRAY_SHADOW=6
GRAY_OVERLAP=
GRAY_GAMMA=1
GRAY_CURVE=/Users/BABAK/Desktop/test/Ron reader/redcolour2.acv
COPY_CURVE_C=K
COPY_CURVE_M=K
COPY_CURVE_Y=K
COPY_CURVE_LC=LK
COPY_CURVE_LM=LK
I have worked on one of Ron's text files which uses all colours as this makes sense to me. but with his printer there was no LLK ink and I have added this myself.
Input Output
0 1
5 1
10 9
20 27
30 33
40 39
50 47
60 59
70 70
80 81
90 88
95 90
100 95
reating curve redcolour-2-3
## QuadToneRIP K,C,M,Y,LC,LM,LK,LLK
# QuadProfile Version 2.7.7.0
# K curve
0 0% |
11 4% |mk g
21 8% | mk g
32 13% | cmk g
43 17% | cm k g
53 21% | c m k g
64 25% | c m k g
74 29% | c m k g
85 33% | c m kg
96 38% | c m g k
106 42% |Y g m k
117 46% |Y g c m k
128 50% |Y g c m k
138 54% |YM g c m k
149 58% | Y g c m k
159 62% | Y g c m k
170 67% | Y g c m k
181 71% | Y g c m k
191 75% | Y g c m k
202 79% | Yg c m k
213 84% | Yg c m k
223 87% | YM c m k
234 92% | YK c m k
244 96% | Y cKm k
255 100% | Y M K
I did try incrasing grey highlights from 0 to 1 , but to the detriment of all the values.
I am sure I am making many rooky mistakes and would appreciate some help on this.