200 line washed out

[Dali555]

We are looking to print more 200 line screen and when we first attempted it, the photos looked "cleaner" but also very washed out and lacking any highlight or midtone.... Are we doing something wrong? We calibrated like normal.....

Marc

[gordo]

We are looking to print more 200 line screen and when we first attempted it, the photos looked "cleaner" but also very washed out and lacking any highlight or midtone.... Are we doing something wrong? We calibrated like normal.....

Marc

Are you printing offset or flexo or?

CtP or film?

What do you mean by "We calibrated like normal.."

best, gordon p

[Dali555]

Oh sorry,
offset, CTP using a Fuji Luxel Vx6000 and by normal I mean, like we did to set up all the other profiles for the press.

[gordo]

and by normal I mean, like we did to set up all the other profiles for the press.

Well, you know what you did to set up all the other profiles for the press means but I don't think anyone else would. Could you briefly explain what you are doing and how?

best, gordon p

[Dali555]

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?

[gordo]

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

[Stiv]

So you linearized the plate.

I would verify that your plate is able to hold a fine dot.

[Dali555]

Yeah that is what we do, figured it was what everyone does on a RAMpage system to target their presses.

[TerryWyse]

Yeah that is what we do, figured it was what everyone does on a RAMpage system to target their presses.

Doesn't sound like you've targeted the *press* so much as you've targeted the *plate* by linearizing the plate.

On the other hand, you say...

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?

This sounds more like you printed some test targets, measured the dot area, and possibly entered that in as you "Actual" values in RAMpage. If that's the case, what did you target for the "Desired" curves? I can tell you this, if you left the Desired curves set to "linear" or "NONE", then you're attempting to print linear which would result in the what you described at the beginning (too clean and possible loss of highlight dot).

While plates may or may-not be linear (50%=50%), a press should NEVER print linear where a 50% dot on plate measures as 50% using dot area on a densitometer. There should ALWAYS be some gain associated with the printed result. Depending on what printing condition you're targeting, this dot gain (or non-linear print condition) should be in the range of perhaps 15%-25%...point is, there should never be a measured dot gain of 0%.

Regards,
Terry