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screen printing => 4 Color and Simulated Process Printing => Topic started by: Rocfrog on August 28, 2013, 01:40:51 PM

Title: CMYK Process.....??? Help
Post by: Rocfrog on August 28, 2013, 01:40:51 PM
Ok so the new shop I'm at now has printed CMYK in the past with little to no problem but we just tried one (first one since I've been here) and it is printing no where near close to correct....

So normally they out put the image via Photoshop using the Channel mixer to "knock back the color some"...settings are C=85% M=75% Y=85% K=85% and then print the channels via a RIP software at 50LPI 22.5 angle and then burn on a 305 screen. But with this process our image is printing more purple than blue....

Here is some screen shots/pics....

Here is the original image
(http://img.photobucket.com/albums/v620/Rocfrog/Screen%20Print/Origonal_zpsf213e24f.jpg)

Here it is in RGB in Photoshop...
(http://img.photobucket.com/albums/v620/Rocfrog/Screen%20Print/RGB_zps7870c411.jpg)

And here it is converted to CMYK
(http://img.photobucket.com/albums/v620/Rocfrog/Screen%20Print/CMYK_zps66303270.jpg)

I also ran it thru our "spot separations" action/plug-in
(http://img.photobucket.com/albums/v620/Rocfrog/Screen%20Print/Spotprocess_zpsc2dc557f.jpg)

Now these all look blue with the excetion of the last one which went kind of purple....

Now here is the actual prints which went WAY purple!!
(http://img.photobucket.com/albums/v620/Rocfrog/Screen%20Print/image_zpsb5bd7bc7.jpeg)

(http://img.photobucket.com/albums/v620/Rocfrog/Screen%20Print/image2_zps51a85d31.jpeg)

And print order is YCMK....

Please help me understand what is going wrong here, I am completely new to this type of printing but the owner is not and he is confused as well....

Nick
Title: Re: CMYK Process.....??? Help
Post by: dirkdiggler on August 28, 2013, 01:44:45 PM
cmyk is a gamble.  You can get great results, but NEVER try to match someones logo that is color specific!  Live and learn.
Title: Re: CMYK Process.....??? Help
Post by: ScreenFoo on August 28, 2013, 02:55:08 PM
Either there is too much magenta in your original sep, or your magenta is gaining too much on press.  BTW, even the pellon is going to be pretty inaccurate, your gain is likely to change on a shirt.

Doesn't really look like a good candidate for 4cp. 
Why not just do black, yellow, and blue?  Better color rendition and way easier on press...
Title: Re: CMYK Process.....??? Help
Post by: shellyky on August 28, 2013, 03:12:39 PM

Doesn't really look like a good candidate for 4cp. 
Why not just do black, yellow, and blue?  Better color rendition and way easier on press...

ditto.  print that out on your ink jet printer and i bet it comes out purple looking too...true blues are hard to hit in CMYK...
Title: Re: CMYK Process.....??? Help
Post by: Sbrem on August 28, 2013, 03:15:32 PM
 I have to agree; I can't see a reason to do this with CMYK...

Steve
Title: Re: CMYK Process.....??? Help
Post by: Homer on August 28, 2013, 03:24:43 PM
if this is still set up, switch your print order YMCK, on press you can base down your magenta, strengthen your blue by adding a wee bit of standard plastisol...don't tell anyone I said that though. I worked at a shop many many years ago that would print everything and I mean every. single. order in cmyk....the smell of union process inks sends me into the deep end..

and I agree, this isn't really a process print....sup with that?
Title: Re: CMYK Process.....??? Help
Post by: blue moon on August 28, 2013, 03:25:52 PM
as mentioned, you have too much magenta, either on press (are all of your screens EXACTLY the same (mesh and tension), same duro squeegee, same angle, pressure . . .)? Any on of those will create imbalance or in seps. If the spes look pretty close, it's in the screens/press.
Rested the settings on the squeegees and reburn that screen, you'll probably get back to normal.

pierre


Title: Re: CMYK Process.....??? Help
Post by: 3Deep on August 28, 2013, 03:51:14 PM
People forget sometimes, a big part of printing is learning which printing process to use, and this one is a spot color job for sure, but good luck keep working you'll get it done.

Darryl
Title: Re: CMYK Process.....??? Help
Post by: Rocfrog on August 28, 2013, 05:35:06 PM
Thanks for all the great responses.

We did take this off press for now so we could move onto other jobs, but we did discuss printing this spot process (which is all I know, this whole process/CMYK printing is completely new to me but this shop has been doing it for some time now) and I think we might go that way vs messing around with this, I think the owner was just trying to find the easiest way to output this which is how he came to the CMYK process.

Nick
Title: Re: CMYK Process.....??? Help
Post by: Inkworks on August 29, 2013, 12:37:52 AM
if this is still set up, switch your print order YMCK, on press you can base down your magenta, strengthen your blue by adding a wee bit of standard plastisol...don't tell anyone I said that though.

These were my two first thoughts too, particularly changing print order to YMCK or YMKC. You could also try cutting back on the magenta by cutting it 1:1, 1:2 or even 1:3 with a untinted process base, soft hand clear or the like.

Since you already have the screens burnt I'd chase down the right print order and cyan and magenta strengths, but that job really screams spot colour.
Title: Re: CMYK Process.....??? Help
Post by: Sbrem on August 29, 2013, 09:55:05 AM
I think you'll spend too much valuable time trying to get it right. It's probably much faster to tear it down and get printing something else while the job is re-output as a spot color job... my 2 cents anyway

Steve
Title: Re: CMYK Process.....??? Help
Post by: mk162 on August 29, 2013, 10:00:39 AM
and this is why I hate 4CP.  we used to run it all the time, until the GT-541(and the prototype before that).  Once we got that it was so much easier to print them on there and not worry about seps, films and so on.  it also freed up the press for other jobs.

yeah, i'd go spot color on that one.  heck, it looks like 4, maybe 5 colors anyway.
Title: Re: CMYK Process.....??? Help
Post by: Sbrem on August 29, 2013, 10:16:49 AM
Funny you should say that Brad. We're just discussing whether or not to DTG a 4cp job we usually print; it's only 24 pieces. So we have to remake screens, set up, you know the drill. Or get the file tweaked so it looks right and just go DTG. To me it seems to be a no brainer. I don't mind 4CP, as we've printed it for a lot of years, but the short run no longer makes any sense since we got the GT-541. Sorry to derail the thread Rockers...

Steve
Title: Re: CMYK Process.....??? Help
Post by: Rocfrog on August 29, 2013, 08:10:03 PM
Well after he had me re output the films after dropping the magenta back another 25% and then isolating the "navy's" and output them as a spot channel. Then he disappeared in back for a most of the day and at one point had it closer and so he went as fiddled some more and then came back with another test print that was a tad closer, and he thought it looked good enough to run....


After going thru all this I agree 110% I agree with you guys, I could have easily made this a spot print with halftones and it would have been off the press in no time. I'm still new here so I can't go pushing my opinions around yet, but this was a good learning experience for me.

Nick
Title: Re: CMYK Process.....??? Help
Post by: mimosatexas on December 09, 2013, 04:46:29 PM
I'm not sure why this would be printed with cmyk.  That requires more screens and more precise registration and more testing that just doing it as spot colors.  There are no gradients and it is so few colors, it just doesn't make sense.  Even done properly with CMYK it won't be as vibrant and clean looking as a spot color print.
Title: Re: CMYK Process.....??? Help
Post by: 1964GN on December 31, 2013, 07:09:42 AM
I spend my days trying to match RGB colors in CMYK... it's not easy and some colors you'll never hit. While I think this should be a spot job if you want to try CMYK you may need to dumb it down a bit. On the yellow go 100%. On the blues... go 100% Cyan then gradually add Magenta to your other blues. On the next darker blue add 5-7%M, next 10-13%, etc.

You can also choke the magenta a pixel to make registration a bit easier on the press. I would also rip out all of the black.

We have been doing it for years and have custom color profiles and values for all of colors. This for heat transfers not directly on garments but the concept is the same.