anyone know how to find what angle the Default Spot Angle is? XMF
We have a job we have printed for 15 years different presses different line screens
and no problems, this went out to an outside printer and an image moire'd
we have had these printed at other printers without problems also
the image is a scanned 1200 dpi, 1 color
I see that they did use a different screen angle in the printed piece
I'm sure you smart guys can give me some insight on why this happened!
If the image is only 1/c, there should be no possibility of a moiré at any angle...
unless the scan was a re-screen and the moiré is in the image.
If the image was more than 1/c, the usual suspect is that the default non-process color angle is the black angle and it needs to be changed for that job.
If it's a 1-color job, I doubt very much that the angle matters other than some angles will give you jagged sawtooth edges along screened areas (we use 45 degrees to make edges clean.) What may have happened is the plate was imaged at a res that is not evenly divisible by 1200, or perhaps the 1200ppi image got re-sampled somewhere in the workflow.
(Dammit, born beat me to the punch as I was typing!)
"What may have happened is the plate was imaged at a res that is not evenly divisible by 1200"
Whoa, like a machine-pixel moiré... that sounds so crazy it just may be true!
what about 2540?
that used to be the default res... in the olden days
:old:
That's what I was thinking. I also worked at a book publisher a few years ago and they still ran film, and on big jobs would image the film at lower res to make it image faster.
Quote from: david on March 10, 2021, 01:45:00 PM
what about 2540?
that used to be the default res... in the olden days
Yep. 2540 / 1200 = 2.116666666666667 = FAIL.
2400 / 1200 = 2 = SUCCESS.
Since we're throwing out crazy theories...
does the paper have a textured pattern?
:banana:
I don't think the math is a crazy theory. Back in the day when we were switching from shooting paper on a camera to instead scanning a screened print we would scan it as line art at a value that was half (1270) of our filmsetter resolution (2540) and it worked great. If we scanned it at 1200 or any value that wouldn't go into 2540 evenly we would get a moire. Of course that was for screened images. With screened images the filmsetter would not re-screen it if it was a value that was evenly divisible into 2540 and it would use the existing screening in the image. But if it wasn't a value that was evenly divisible into 2540 it would try to re-screen the screen which produced a moire.
You're right, I guess I meant "crazy" as in brilliant / less obvious... like "wow - that's crazy!"
My paper idea on the other hand, that's just crazy.
Quote from: born2print on March 10, 2021, 03:04:39 PM
You're right, I guess I meant "crazy" as in brilliant / less obvious... like "wow - that's crazy!"
My paper idea on the other hand, that's just crazy.
I've seen crazier things in this business. :rotf:
I mean hey - that's how lenticular works, right David? :sarcasm:
yes, the altering the output res is how you adjust/scale the lenticular file to fit the plastic.
thank you Kodak
it's been a while since I did any of that.
:old:
oh, lenticular sucks...
:drunk3:
Sorry to bring it back up! :puke:
:laugh:I knew that would bring you guys out!
I will gather my image and a pic of the printed image.
I thought the same thing about the 1 color and the image being rescreened
or maybe the resolution lowered somehow, It is a 1200 dpi scan of a previous printing I do believe
so it was a copy dot scan not rescreened and being 1 color the screening shouldn't change
It never has for us, but being as we are not the ones who printed it, who knows how they output it.
Who output the plates and at what resolution were they output? I think that is the key to your question.
Is this your image? If so, it will always show a moray. Or, if the moon hits your eye (like a big pizza pie), that will also produce amoré.
Thanks Joe! I think that is the question I need to ask, I cannot replicate the problem
I will try and find the answers to the questions.
Attached is the pdf of the image
I will take a pic of the moire when I can, not a big phone person and got some work to do :laugh:
I'm betting somehow, somewhere they re-screened your screen. I'll also wager that there was no moiré in the 15% tinted box.
correct only on the globe, how would somebody rescreen at the workflow?
The platesetter will re-screen if it is a resolution that won't be evenly divided into the output resolution. The image is 1200 dpi so it either needs output at 1,200, 2,400 or 3,600 dpi. Anything else will cause it to re-screen the screen. Or at least that was how it was when years ago we had to input a bunch of screened images.
Huh! I had no idea!
I will report back when I know more
are most image setters 2400?
the 1200, 2400, 3600, totally makes sense to me
If I remember correctly, "most" imagesetters can output at 1200, 2400 and 3600 as options?
So maybe they pick 2400 for everything. Or maybe they do 85 line at 1200, 133 and 150 line at 2400 and 175 and up at 3600?
:laugh:
Just thinking of you, you were the one that taught me Lpi, Dpi, Ppi, it's all coming back!
:hello: Raster them pixels!
Quote from: born2print on March 11, 2021, 11:07:03 AM
:hello: Raster them pixels!
new band name:
Rasterd Pixels
:lmao:
Ok their image setter is at 2500, thanks guys
I would not have known to ask this.
Their prepress is telling me if you open up the image in photoshop at 89% you will see the moire :laugh:
Wait, so they are implying that your image has the moiré before their RIP.
Maybe so if a rescreen...
but a monitor has a pixel resolution that can mesh (or mis-mesh) with the copydot scan and have a moiré - ok fine...
but that is an entirely different thing than an imagesetter resolution mis-mesh.
I am skeptical, if your image had the moiré already, it might view at more than just 1 specific scale on the screen...
and wasn't it a copydot? IMO, a copydot can't have a moiré in it - that's the point of it... so that would imply the image got ruined in their RIP.
Furthermore, I got the impression that you do this often and without issues until it went to a vendor?
:homer:
Quote from: Tracy on March 11, 2021, 12:10:40 PM
Ok their image setter is at 2500, thanks guys
I would not have known to ask this.
Their prepress is telling me if you open up the image in photoshop at 89% you will see the moire :laugh:
1st off they should have their a$$ kicked for opening a perfectly good PDF in Photoshop.
Quote from: Tracy on March 11, 2021, 12:10:40 PM
Ok their image setter is at 2500, thanks guys
I would not have known to ask this.
Their prepress is telling me if you open up the image in photoshop at 89% you will see the moire :laugh:
And also...2500 / 1200 = 2.083333333333333 - moire.
Quote from: Joe on March 11, 2021, 12:48:07 PM
2500 / 1200 = 2.083333333333333 - moire.
BOOM! :drop the mic:
Quote from: born2print on March 11, 2021, 12:36:25 PM
Wait, so they are implying that your image has the moiré before their RIP.
Maybe so if a rescreen...
but a monitor has a pixel resolution that can mesh (or mis-mesh) with the copydot scan and have a moiré - ok fine...
but that is an entirely different thing than an imagesetter resolution mis-mesh.
I am skeptical, if your image had the moiré already, it might view at more than just 1 specific scale on the screen...
and wasn't it a copydot? IMO, a copydot can't have a moiré in it - that's the point of it... so that would imply the image got ruined in their RIP.
Furthermore, I got the impression that you do this often and without issues until it went to a vendor?
:homer:
You can see a moire in any screened image in photoshop if you view at a certain size which has nothing to do with outputting the file. It's just a weird pattern on the monitor at that point.
Scale it to 1,250 dpi and it would output perfectly at 2500. And 2500 is weird resolution. Most high end output devices are 2400 or 2540. I think the 2540 is what most filmsetters were at back in the day.
Our old Luscher platesetters wouldn't allow us to change resolutions. Everything had to be at 2400 dpi or would scale the image. We have two new ones now, a Fuji Javelin and a Screen Ultima so I'm not sure if we could change the resolution now or not. We just run everything at 2400.
And it may actually be the workflow that rescreens the screen when it is screening the one bit tiff. It's been awhile ago since I had to deal with stuff like this.
If you take that image and upscale it to 2500 in Photoshop you will see moire at several different magnification values. But at 100% you never see the moire.
where did they get a setter that has a 2500 res output?
never seen one of those.
:drunk3:
Quote from: david on March 11, 2021, 01:04:39 PM
where did they get a setter that has a 2500 res output?
never seen one of those.
:drunk3:
Somebody probably got a deal...
:facepalm:
You guys are priceless! seriously, I got to go into the meeting knowing what I was talking about
and yes we have printed this for 15 years various presses and vendors, I made a plate this morning
to take to the meeting with me, it was good to have all my ducks in a row.
I know I was asking the guy, "why are you opening it in photoshop"
he was trying to prove his moire point
It's an AGFA, curious if they just got it or something, they would not hear about the resolution until
I got to speak to the prepress manager, he said he would look into it.
so we cannot have them print this job there anymore, It's a pretty big job too
12 different forms, usually pretty big runs
Customer hasn't seen it yet, run was kind of large so it may take awhile for them to catch it.
Change resolution to 1250 with Pitstop on the globe image. Have them test a new plate at 2500 dpi. My money, though I have none, says that it will look fine.
ok I will let them know! not sure if they are interested but I will try
I learned so much from this too!