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screen printing => Separations => Topic started by: JBLUE on July 19, 2011, 10:49:58 PM

Title: Scaling down a DCS
Post by: JBLUE on July 19, 2011, 10:49:58 PM
Heres one for you guys. I have really never had the need to scale down a DCS file that significantly. Once brought over to Illustrator if I shrink it down to say 60% of the original sepped file.  Will it still hold a 1 or 2 pixel choke for the base? I have always just sepped two files instead of scaling it so that would be a timesaver if it still held the choke information as its scaled down. Thanks
Title: Re: Scaling down a DCS
Post by: ebscreen on July 19, 2011, 11:16:36 PM
I would recommend against it. Scaling does weird things to raster files, and if it's already sepped it might blur your edges etc. I always sep raster at the size it will print.
Title: Re: Scaling down a DCS
Post by: ZooCity on July 19, 2011, 11:53:27 PM
I figure the whole purpose of .dcs is so that, once saved nobody can screw with it.  Scaling significantly (or at all) might well be considered trying to screw with it.   Whoever got the file to you shouldn't have a problem scaling the original and re-saving. 

Then again, I haven't mastered the file type yet.  I get real damn close every time but there's always something wrong with one of the plates- usually some b.s. like a solid or 98% fill area getting a 40% looking fill out of the rip -and I have to go back and rehab that color.  So I could be dead wrong and maybe it's kool and gang to scale .dcs files in Illy....but, pretty much what eb said. 
Title: Re: Scaling down a DCS
Post by: Denis Kolar on July 20, 2011, 08:36:34 AM
If you save the file with certain settings like LPI, scaling would change the size of the dot.
If you save the sep with 55lpi, when you scale it 60%, would that make the LPI to be somewhere in the range of 90?

Title: Re: Scaling down a DCS
Post by: Sbrem on July 20, 2011, 08:51:35 AM
If you reduce the file dimensions, you also reduce the choke. Illustrator controls the halftones, unless you converted each channel to bitmap/halftone mode first, but I don't see why one would do that for a DCS. The 2 pixel choke is a "physical", so to speak, thing, so if you reduce the file to 60%, that just goes along with it, down to a 1.2 pixel choke. Set your line count (LPI) in the Illustrator and print it out.

Steve

Title: Re: Scaling down a DCS
Post by: JBLUE on July 20, 2011, 10:52:05 AM
This ones just a simple spot color so no halftones involved.  Besides my RIP overwrites anything that PS or Illy does. It ignores both of them and prints the LPI that I have set in the RIP itself. So for a halftone base I would think that shrinking it down, it would still hold the information that the white base since it is smaller than the top colors. I never thought of trying so I may have to print out a film and try it.
Title: Re: Scaling down a DCS
Post by: Sbrem on July 20, 2011, 02:05:53 PM
We over ride our RIP and use Illy's, but that's pretty much 6 of one and a half dozen of the other. If you want to maintain the choke, maybe it'd be best to reduce in PS first, reset the choke to the desired 2 points, and go back to Illy.
Title: Re: Scaling down a DCS
Post by: JBLUE on July 20, 2011, 02:50:23 PM
I burned a few films and the choke held just fine. By eye and a loop comparing the two films it held its two pixels. So it looks like it worked in this case. I just never thought about it because like most I just sep the two different sized files and printed them out.
Title: Re: Scaling down a DCS
Post by: Dottonedan on July 20, 2011, 08:08:23 PM
We over ride our RIP and use Illy's, but that's pretty much 6 of one and a half dozen of the other. If you want to maintain the choke, maybe it'd be best to reduce in PS first, reset the choke to the desired 2 points, and go back to Illy.


DING DING DING!
   ;D  Follow each post here by Sbrem and you have the most accurate answer. All have merit but his is dead on.

This story reminds me of my early days.  WOW, what I sued to do to get a good sheet of film.  Back in the day, we had 300dpi laserprinters. We were BIG TIME where we went to 600. Any who, I worked at a glass factory in the  art department. we were unionsized and art department and make %7.65 across the board. Young and old, experienced and not.

Anywho, I was usually very happy when I got jobs that were one sided. This meant quality. Reason being, I would be able to take a one sided imprint on a glass or coffee mug and double the size in the file. Then print it out on our 300dpi paper laserprinter at 35 line screen, send it to the camera room for a film reduction at 50% thus providing a actual size print at 70lpi halftone. That made it a little crisper like as if we were already using a 600dpi printer.  Then came the 600dpi printer. WOW, imagine the quality we were putting out now for a 1 sided print.  Full wraps were less desirable.

It's amazing what one comes up with when you need to or when you have nothing and need to make something.
Title: Re: Scaling down a DCS
Post by: Sbrem on July 21, 2011, 09:30:14 AM
Aw shucks, thanks Dan. Your story reminds me of something we used to do with the camera and halftone screens. We couldn't get a halftone screen below 65 line, so we would shoot/halftone at 75% onto paper instead of film, then enlarge those to 133% (to bring it back to the original size) and end up with a 40ish line halftone... necessity is a mother

Steve
Title: Re: Scaling down a DCS
Post by: Artelf2xs on July 29, 2011, 06:23:47 PM
houze on first Dan :-)

reminds me of when we used to use the Dinosaur poop as block out.... :o

I reduce my DCS files in Illy all the time however I don't do solid graphics in bit map.....