Tints in solids?

NJservice

Well-known member
I was working on an ECRM imagesetter last week.
I was there for the RIP mainly, as I don't work on that imagesetter.
(If anyone has directions for cleaning the optics, I'd love to know how!)
I did an exposure test, as the initial jobs looked overexposed, and the first calibration curve was way off.
It's been a while since anyone looked at this machine, so out of habit, I trashed all the cached screen patterns. I also had to get rid of some page setups they were never using, and make spool folders, as they are using OS 10.6, and Apple talk is done.
When I looked at a laser test, I saw Dmax from 4.1 @ light of 50 to about 5.1 @ 90.
I picked the setting just over the "shoulder" of the DMax curve, where it was stable.
I set the laser to 90, where it had been at 100. So I set it down, just a bit.
I didn't like the film though, as it looked very plugged up.
When I took numbers for a curve, the first 3 steps or so were solid, pretty much, and 50 was at least 10 points off. I put my readings in, and the calibrated curve looked perfect.
I explained, though, that this is throwing many values away, and they could get bad vignettes, etc. I was thinking, if the optics were dirty, the light could be fringing, and making the exposure blotchy. Perhaps a cleaning would make a uncalibrated 50 close to a 50%?
Well, that didn't seem to matter. The problem I have is that film, and even preview, is showing a slight tint in solid areas. So a solid black envelope, with text, has a tint in the solid.
I sort of went right to the problem, over the phone today, and had her set calibration to "none". She ran a job, roamed it, and it looked good. When we picked the 2540 calibration, the dots came back.
I also had her check , in Calibration Manager, that "Force solids" was checked, it was.
So, I'm going back in tomorrow.
I was reading about these kind of problems and "rich blacks" or settings in the job that could cause this, but this seems, from my test over the phone, to be related to the Calibration function. She also said that the calibration strips looked good from last week, the solids were solid, except for the last few calibrated curves, which she said have the dot pattern.
Anyone have any ideas?
 

davec

Active member
Tint in solid

Tint in solid

Hmm. Can't be anything to do with the imagesetters laser if you see it in the preview

Sounds like conflicting settings. Does this happen when you are ripping a single colour job?

I would go back to default settings for everything and see what happens!
Good luck!
 

NJservice

Well-known member
Thanks Davec,
I went there today, just got home.
When we turned Calibration off (select none for 'calibration') the images were fine, solida were solid. With it on, the solids had tiny dot screens. This happened even on the Calibration strip, so I knew it couldn't be settings in the jobs, etc.
I turned off Calibrations in all page setups, threw out all cached screens, deleted the calibration curve and made a new on.
I imaged the cal strip, read the numbers, edited the curve (so the Status of the curve became "U" for "Use") and throughout, the solids stayed solid.
We ran some jobs, and all the screening in solids was gone.

I only mentioned the cleaning of optics because at a good density, the 50% uncalibrated dot was about 30%, and the first 3 steps were almost completely solid. The RIP did calibrate this to 'perfect' results +-1% for all steps, but I explained how this could lead to crummy results on vignettes, or even smooth gradations on faces, etc.
I can't help but think a film of dust on some mirror could be making these plugged up dots. I don't work on ECRM machines much though.
Oh, and people suck too.
I went there last Thursday, spent the afternoon, simplified many of their RIP settings, switched their inputs to Spool Folders from Appletalk, etc, etc.
The problem only showed up after I left. It must have happened on the last 'fine tuning' of the curve (sending the curve status to "C"), and the film was never exposed as a last check (it was getting late, etc). So they ran film Friday and Monday, and didn't notice these dots until Monday afternoon. They called me yesterday at 4:30, and I even offered to go then, and be there by 6:30, but we decided first thing today. (1.5 hr away)
So, I threw out the corrupted curves, recalibrated, and this also fixed a moire issue they were having.
At the end of the call, I decided to just charge them $200 for the 3 hours or so I was there.
They were surprised, "I didn't think we'd get charged".
Well, it wasn't my fault the RIP had a corrupted cal curve either, so I'm only charging $200 considering anything. They also added how much money in the 40 feet of film they ran was wasted and after all "there wasn't a problem before you were here, but there was after"
uh huh... if there wasn't a problem before I was there, WHY was I there?
Anyway, rather than talk to her brother about it, I figured life is too short to worry about $200.
They also did this a year or two ago to cut their bill in half, and I told myself I wouldn't go back!
Oh well, next time they call, I'll tell them I could come in Saturday afternoon. When they say they're not working Saturday, I'll tell them "neither am I! but this is a hobby, right?"
 

davec

Active member
Haha. Good follow up post. V amusing!

I don't know ECRM Imagesetters, and have only worked with 1 Herkukes (v1!)

If the dot is seen in the preview. Then it has nothin to do with the imagesetter.
By settings, I didnt mean job settings, I was meaning screen and or page set up.
What happens when you create a flat calibration 10=10
20=20 etc?

I'll look tomorrow as I can't remember the exact terms used!
We are now using a Compose RIP, which is based on harlequin. So should be v similar
 

RGPW17100

Well-known member
This was a long time ago and I am not the expert but we had an ECRM MAKO2 and we were trying to create a manual curve. By doing this we would read the dot and then increase the value into the calibration curve to try and create a simple dot gain curve to put the 20 percent in the middle and make it so there was no gain on either end. By doing this we encountered what you were experiencing. When we changed the values of the screens 90 percent and above we started getting a 98 percent dot on all of our solids.
 

NJservice

Well-known member
interesting RGP,

interesting RGP,

I seem to remember seeing this in solids too, but it was so long ago!
It must be a bug in the software, because making a new curve solved the problem.
Also, it seems like having "Force Solids" checked would solve this, but it didn't.

Again, I don't like the curve having to do so much work, as it wastes a lot of gray levels dragging 30% up to 50%, and the first 3 steps (2,4,8?) being nearly solid. But I also wanted the exposure curve to be above the "shoulder" of the curve for DMax.
That's why I would love to be able to clean the optics, to make sure that wasn't the reason our uncalibrated 50% was so plugged up and reading 30%
 

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