Sorry, figured with it being in a RAMpage forum that people knew what I meant. I mean that we run a test pattern on the press to baseline... take a press sheet and get the values for all the tints.... put them into RAMpage and get a set of curves and then run to that.... makes sense?
You're not providing clear information as to what you are doing. E.g. What do you mean by "baseline".
I'll try to briefly explain the process of building dot gain compensation curves in a workflow neutral way because the process itself is for the most part workflow neutral. I.e. See if it aligns with what you are doing. You can get a more detailed explanation (with images) here:
Quality In Print: The principle of dot gain compensation plate curves
The steps:
1) You must have an existing tone reproduction target. That is usually your existing presswork but it could also be an industry specification. (You do not say what your target is nor what your current lpi is)
2) Your current presswork must be consistent and repeatable. You can't build curves for an unstable process.
3) The plates and CtP must be qualified for the new lpi (You do not state that they are)
4) You image tone step wedges (preferably no pictures) onto unlinearized plates at the new lpi (Unlinearized means that no curve is applied to the plate) (You do not state how your plates are imaged)
5) You run the plates on press at your standard solid ink densities - do not have a proof at the press. (Is that what you mean by baseline?)
6) You run enough sheets at density to ensure that the press is stable.
7) You check the integrity of the presswork (i.e. no slur, doubling, etc.)
8) You measure the tone response of the presswork (dot gain or final tones - this part is workflow specific) and enter into your system.
9) the system uses those two pieces of information - target tone desired and current tone response - to build a tone reproduction compensation curve for the press.
10) You image a new set of plates with tone step wedges (with pictures if you like) and with the curve applied at your desired lpi.
11) You run the plates on press at the same SIDs as your first test plates. Again - no proof at the press.
12) You run enough paper so that the press is stable.
13) You measure the tone response to ensure that the applied curve is aligning the tones to your target.
Does that basically describe what you did? If not where does it differ.
best, gordon p
