From Leica Photography Magazine some time in the 1980`s. Article by Rudolth Seck. I only have the chart in my darkroom and it crumbled when i took it down for this. The mags are in storage.
Grade - Yellow - Magenta - Exposure factor
0 ----- 120 ---- ------------ 3.0
.5 90 2.5
1 60 2.0
1.5 45 1.7
2 30 1.6
2.5 15 1.2
3 normal 0
3.5 15 1.3
4.0 30 1.5
4.5 90 2.0
5 200 2.5
The advantage of using the color mod is so normal or near normal grades have faster printing speed. You could start adding extra neutral density to middle grades to even out the eposure factor. 30 each YMC is one stop. 60 is two. This is how the VC module is calibrated so you lose a bunch of speed to maintain the same exposure factor. When I look at mine it is just a yellow to magenta graduated filter controled by a single dial.
I don`t use it much.
0= extra soft
1=soft
2=special
3=normal
4=hard
5=extra hard
Like all VC exposure compensation, it is for middle grey. Whites and blacks are different. Add some extra if you want the blacks to be the same. Subtract some if you want the whites the same. The VC module works the same way as do VC filters
Upon entry, the program ran all the colums together. I can`t fix it. Less than grade 3, Use only yellow. Greater than 3, use only magenta. Sorry
