Create curve in Rampage

Greg08

Active member
Running Rampage 10.5 and would like to know the steps on setting up
curves. We added a new press and our standard linear profile is not
working. Thanks for the help.
 

TerryWyse

Well-known member
In the Rampage Client, open the Calibration Editor. Use "Media Linearization" curves to calibrate/linearize the plate...use "Dot Gain Compensation" curves to adjust the dot gain/TVI of the press.

For Dot Gain Compensation, if you have a target TVI curve in mind, that would be used as your "Desired" curve. To complete the curve setup, you have to run a press test at standard densities using LINEAR plates and then measure several press sheets to obtain the "Actual" curve. When you then select both the Actual and Desired curve when imaging plates, you should end up with very close to the target TVI on press.

There are other curve scenarios such as G7 calibration where you may or may not use both the actual and desired curves. Generally for a G7 calibration, you leave the Actual curve at "None" or linear and create a Desired curve using G7 calibration values from either the CHROMiX Curve/Curve2 software or use the manual "fan graph" paper method.

There is a lot of nuance (and knowledge) on how to approach all of this...but this is the basics.

Terry
 

Greg08

Active member
What I did was ran a linear plate and recorded what the press was printing.
I took those measurements and created a profile (Actual Ryobi) then created
a profile called Desired Ryobi (true screen percents).
When ploted to plate I chose no media lin., Actual Ryobi (press A) and
Desired Ryobi (press D)
Hope this makes sense.
Is there a better way?
 

buckeye

Well-known member
Did you select a media linearization when you ran your linear plate? I would think that you would want to choose a media linearization when plotting to plate along with your Actual and Desired Profile, if that's what you did for your linearized plate.

I have heard of some people though, preferring to run their test plate WITHOUT it being linearized and then letting Rampage adjust accordingly from there.

Thanks,

Erik
 

Raymond Ramirez

Well-known member
Did you select a media linearization when you ran your linear plate? I would think that you would want to choose a media linearization when plotting to plate along with your Actual and Desired Profile, if that's what you did for your linearized plate.

I have heard of some people though, preferring to run their test plate WITHOUT it being linearized and then letting Rampage adjust accordingly from there.

Thanks,

Erik
I have seen people do it 2 ways.. Just like you did or linerize the plate.
Then apply the press curve on top of the linerized plate. This is done this way
Because if you have a major shift in color you can check your linerization on plate instead of going through the process of fingerprinting the press.
This will also establish if there is a problem on press or the plate. The way you did it is ok if you have a consistant plate. If you think your plate manufacture drifts then the linerization with a press compensafion is bettter desired.
 

buckeye

Well-known member
Makes perfect sense to me gordo. Less is better. We currently run the two curve set-up but I would like to change it to one. The next time we do a footprint of our press, it will be without plate linearization.

Erik
 

danremaley

Well-known member
Makes perfect sense to me gordo. Less is better. We currently run the two curve set-up but I would like to change it to one. The next time we do a footprint of our press, it will be without plate linearization.

Erik
I have read a lot of posts regarding linear or non-linear plates. Here's what my 40+ years of experience has taught me. Linearize the plate FIRST, no, you don't have to, BUT, if you do, then #1-we are sure that the plate is printing a 1-2-3-4% dot and #2-we "know" what a 1-2-3-4% dot area should be on press. #3-when management changes plates cause they got a 'better deal' - all you need to do is linearize the "new" plate, all your curves still work!
Also- Creo, and later Kodak use to 'over expose' their positive plates, to make sure the background came off easily to prevent tinting, on press. Many shops I visited a 50% measured 44-46%.
Dan Remaley (former GATF)
 

gordo

Well-known member
I have read a lot of posts regarding linear or non-linear plates. Here's what my 40+ years of experience has taught me. Linearize the plate FIRST, no, you don't have to, BUT, if you do, then #1-we are sure that the plate is printing a 1-2-3-4% dot and #2-we "know" what a 1-2-3-4% dot area should be on press.
Well a 1% etc. dot size changes according to the dpi of the recording device and the lpi of the requested halftone screen. So, in that sense, even with a curve, you really don't know that the plate is imaging a so-called 1-2-3-4% dot. That's why the installation engineers use single and multi-pixel targets instead when they calibrate a CtP device.

#3-when management changes plates cause they got a 'better deal' - all you need to do is linearize the "new" plate, all your curves still work!
True if you have mass quantities of curves. However, in my experience shops rarely have more than one and if they do they seldom have more than three. If the shop switches to a different plate there are usually other more important issues that arise.

Also- Creo, and later Kodak use to 'over expose' their positive plates, to make sure the background came off easily to prevent tinting, on press. Many shops I visited a 50% measured 44-46%.
I don't think that's correct. They would set exposure to create single pixel checkerboards with clear backgrounds. each plate/processor combination would result in a plate with a different tonal response curve. That would be its natural calibrated state and a curve would then be applied so that the plate delivered the required tone response on press.

Best, gordo
 

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