Author Topic: HELP! Four colour process Photoshop Color Settings  (Read 3230 times)

Offline j20nyh

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HELP! Four colour process Photoshop Color Settings
« on: August 22, 2016, 09:55:35 AM »
Hi all, new member here!

I've been working in the t-shirt printing industry for around 6 years as an artworker mainly and currently 95% of all the printing my shop do is using waterbased ink, in particular the Texcharge ink system by Sericol.

On the whole we produce some pretty good results with 10 colour simulated process prints on light and dark shirts, I can post some examples if anyone's interested but one thing we can't seem to crack is four-colour process prints using the Texcharge Trichromatic inks, no matter what we do they always end up very dark and very muddy so i've gone right back to the art room to try to tweak each variable one at a time and believe that it could be down to the CYMK conversion made in Photoshop, as well as other variables in the screen dept. and on press.

See attached for my current colour settings, can anyone tell me if these can be tweaked to help get a better CMYK separation and help with final printed image?

TIA




Offline Colin

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Re: HELP! Four colour process Photoshop Color Settings
« Reply #1 on: August 22, 2016, 10:32:37 AM »
Does Texcharge offer you a cmyk download?  Its a little file that has the l.a.b. coordinates already loaded up. 

At the very least you will want to do a swatch test for each color and color overlap - then try your best to simulate/Sherlock your way into figuring out what that color space is by comparing the print to the visual that photoshop is giving you.  Then you enter those values into your custom cmyk space.

What are your dot gain settings?  I would start at 40% and adjust from there.  You may need only 25%-30%....

Try medium black generation.  This will make some of your grays a blend of cmy.

Other than that, what is you screen/mesh/squeegee/print set up?
Been in the industry since 1996.  5+ years with QCM Inks.  Been a part of shops of all sizes and abilities both as a printer and as an Artist/separator.  I am now the Ink and Chemical Product Manager at Ryonet.

Offline j20nyh

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Re: HELP! Four colour process Photoshop Color Settings
« Reply #2 on: August 22, 2016, 10:49:02 AM »
Does Texcharge offer you a cmyk download?  Its a little file that has the l.a.b. coordinates already loaded up. 

At the very least you will want to do a swatch test for each color and color overlap - then try your best to simulate/Sherlock your way into figuring out what that color space is by comparing the print to the visual that photoshop is giving you.  Then you enter those values into your custom cmyk space.

What are your dot gain settings?  I would start at 40% and adjust from there.  You may need only 25%-30%....

Try medium black generation.  This will make some of your grays a blend of cmy.

Other than that, what is you screen/mesh/squeegee/print set up?

Thanks for the reply Colin, as far as i'm aware there are no LAB values for the Texcharge Trichromatic inks, I did contact Sericol about this but they seemed completely oblivious as to what I was asking. My dot gain settings in CMYK are 38% for Magenta and Yellow and 40% for Cyan and Black - in the spot channel settings I have the dot gain set to 88% at 50%.

We are using 120 mesh (Threads Per CM) yellow mesh, separations are done in Photoshop for four-colour process prints and sent to our I-Image direct to screen machine at 65 lpi with a round dot at 22.5 - this seems to be working pretty well for our simulated process prints but would you recommend changing for four-colour process printing?

On press the Trichromatic inks are used straight out of the tub in Y, C, M, K order as recommended by Sericol with hard squeegees and at a minimum pressure but enough to clear the screen.

Offline Prince Art

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Re: HELP! Four colour process Photoshop Color Settings
« Reply #3 on: August 22, 2016, 11:55:23 AM »
Check out this tutorial: https://printwearmag.com/features/separations-four-color-process-printing

I don't know if it will help you or not. But after separating CMYK with no help and only so-so prints, I found this & walked through it on a couple of jobs - made a world of difference. And the most obvious improvement was in the black/darker areas - no longer "muddy".

FWIW, we're using plastisol from a different mfr. But we were able to download the color profile for their process ink from their website, and import that into Photoshop. Combined with the rest of the tutorial, this made things a lot easier.
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Offline blue moon

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Re: HELP! Four colour process Photoshop Color Settings
« Reply #4 on: August 22, 2016, 12:09:51 PM »
Does Texcharge offer you a cmyk download?  Its a little file that has the l.a.b. coordinates already loaded up. 

At the very least you will want to do a swatch test for each color and color overlap - then try your best to simulate/Sherlock your way into figuring out what that color space is by comparing the print to the visual that photoshop is giving you.  Then you enter those values into your custom cmyk space.

What are your dot gain settings?  I would start at 40% and adjust from there.  You may need only 25%-30%....

Try medium black generation.  This will make some of your grays a blend of cmy.

Other than that, what is you screen/mesh/squeegee/print set up?

Thanks for the reply Colin, as far as i'm aware there are no LAB values for the Texcharge Trichromatic inks, I did contact Sericol about this but they seemed completely oblivious as to what I was asking. My dot gain settings in CMYK are 38% for Magenta and Yellow and 40% for Cyan and Black - in the spot channel settings I have the dot gain set to 88% at 50%.

We are using 120 mesh (Threads Per CM) yellow mesh, separations are done in Photoshop for four-colour process prints and sent to our I-Image direct to screen machine at 65 lpi with a round dot at 22.5 - this seems to be working pretty well for our simulated process prints but would you recommend changing for four-colour process printing?

On press the Trichromatic inks are used straight out of the tub in Y, C, M, K order as recommended by Sericol with hard squeegees and at a minimum pressure but enough to clear the screen.

how did you pick those numbers?

pierre
Yes, we've won our share of awards, and yes, I've tested stuff and read the scientific papers, but ultimately take everything I say with more than just a grain of salt! So if you are looking for trouble, just do as I say or even better, do something I said years ago!

Offline UltraSeps

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Re: HELP! Four colour process Photoshop Color Settings
« Reply #5 on: August 22, 2016, 01:31:53 PM »
Just loading color settings data intended for process printing on fabric won't help that much.  The seps will still be muddy.  A ton of black data (but not all) also needs to be removed from the c-m-y channels or you'll have a mess on your hands.  The cyan and especially the magenta channels will need further adjustment.  The yellow isn't super critical (usually).

The loading of a proper color settings file assists in making accurate adjustments within Photoshop as it will compensate for dot gain on the screen.  With process, even with the proper color settings loaded, its always a good idea to go with slightly less density, resulting in a somewhat muted rendering on the monitor.

Pulling off a decent CMYK separation without very good separation software to get you started isn't that hard.  Just takes some trial and error.  The best way to learn is to do some CMYK separations with a product known for generating good process seps and compare your efforts to those.
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Offline j20nyh

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Re: HELP! Four colour process Photoshop Color Settings
« Reply #6 on: August 23, 2016, 03:15:32 AM »
Does Texcharge offer you a cmyk download?  Its a little file that has the l.a.b. coordinates already loaded up. 

At the very least you will want to do a swatch test for each color and color overlap - then try your best to simulate/Sherlock your way into figuring out what that color space is by comparing the print to the visual that photoshop is giving you.  Then you enter those values into your custom cmyk space.

What are your dot gain settings?  I would start at 40% and adjust from there.  You may need only 25%-30%....

Try medium black generation.  This will make some of your grays a blend of cmy.

Other than that, what is you screen/mesh/squeegee/print set up?

Thanks for the reply Colin, as far as i'm aware there are no LAB values for the Texcharge Trichromatic inks, I did contact Sericol about this but they seemed completely oblivious as to what I was asking. My dot gain settings in CMYK are 38% for Magenta and Yellow and 40% for Cyan and Black - in the spot channel settings I have the dot gain set to 88% at 50%.

We are using 120 mesh (Threads Per CM) yellow mesh, separations are done in Photoshop for four-colour process prints and sent to our I-Image direct to screen machine at 65 lpi with a round dot at 22.5 - this seems to be working pretty well for our simulated process prints but would you recommend changing for four-colour process printing?

On press the Trichromatic inks are used straight out of the tub in Y, C, M, K order as recommended by Sericol with hard squeegees and at a minimum pressure but enough to clear the screen.

how did you pick those numbers?

pierre

Hi Pierre, i followed the same guide that Prince Art posted: https://printwearmag.com/features/separations-four-color-process-printing

Offline blue moon

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Re: HELP! Four colour process Photoshop Color Settings
« Reply #7 on: August 24, 2016, 12:13:21 AM »
the trick is, you are supposed to measure the output and enter the numbers that correspond to your readings. I am going to guess that 88 is probably too much. Also, posting a picture would help with some diagnostics. . .
Just as an FYI, we are pretty good with 4CP, but have not done it with discharge before, so not sure how relevant any suggestions might be, but the principles are the same so it should be OK.

pierre
Yes, we've won our share of awards, and yes, I've tested stuff and read the scientific papers, but ultimately take everything I say with more than just a grain of salt! So if you are looking for trouble, just do as I say or even better, do something I said years ago!