Transfer Curves and Calibration

[ec_deville]

We are a commercial shop ... we get all sorts of crap... Are most of you using rip level transfer curves to compensate press gain? If so are you entering different values for cmyk or general like say 25% for all colors.
In my mind the gain is not equal across the board. I think a general approach cause color shifts. Any thoughts

[Lammy]

NOPE

When we output film a 30% dot on the file is a 30% dot on the film.

On our proofer we apply a press gain curve for each color.

[Cory]

same as Lammy...not dot gain curve is applied to the film

[pspdfppd]

We DO use transfer curves....

We created them in Agfaset, i'm not sure if that is something you know about.

We found that when using 175 line screening and above..that the 2% to 5% dot was either dissapearing or reducing significantly. Basically, for example, the 3 percent dot is bumped up to 4, the five percent dot up to 6, etc, etc, and then it sort of linearizes with a dot gain at 50% of about 10%. In the high end...like 95 percent or so....the curve goes the other way. The 95 might come out as 93 or so. This is all due to the smaller dot and how it fills in on OUR presses.

Anyway, it's called on a job by job basis.

If you have an apogee rip and would like a copy of our transfer curve, let me know and I can email it to you.

PS

[ubergeek]

We use halftone linked transfer curves with series 3.
AppX has a calibration function that works with the output press TP

the best way to do this is start with a known dot gain curve, and then tweak the individual colour curves to match your press.

Not all inks lay down the same way on the same paper.

If you really wanna get funky, then you need to make a separate curve for every ink/paper combo that your running.

That is what we did.....Damn, it worked.

BTW we're running Cristal Raster on a cold-set newsprint press from film burned onto plates.....someting dat all said couldn't be done...


HA HA

[technoserf]

We're a service provider for a real broad range of printers. It's unrealistic to store accurate curves for all the press/paper/ink combinations. We use standard curves applied in the application for the mid-quality stuff. For people who want accurate compensation we do all the compensation on the front end image editing stage.