# Help with CMYK White Base



## becki4 (Oct 2, 2007)

Hi guys,

I'm relatively new to the T-shirt printing industry and am getting to grips with 4 colour process jobs.

What I wanted to know is what settings to use when outputting a White Base.

I use Illustrator and the current settings I use are:
Cyan - 22.5 - Ellipse
Magenta - 82.5 - Ellipse
Yellow - 7.5 - Ellipse
Black - 52.5 - Ellipse

I've seen online to do a White base at 15 degress as a Dot but wasn't sure as there angles were different all together.

If anyone could verify what settings to use for a White Base and a White Highlight that match the settings I currently use I would be very grateful.

Thanks.


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## jsf (Aug 4, 2009)

becki4 said:


> Hi guys,
> 
> I'm relatively new to the T-shirt printing industry and am getting to grips with 4 colour process jobs.
> 
> ...



Why do you have to make halftones for your underbase? and why is there a need for highlight?  These two things are normally applied in Simulated and Index process, but not in CMYK. 

Will someone correct me if I am wrong.

Normally in CMYK you need a solid white underbase to cover dark color shirts in a way that the inks will blend to give color details because of the inks (CMYK) transparency.

For example, if you will be printing a squared picture on dark shirt, you need to apply a solid square underbase. Also if the picture is round then the underbase would be solid round.


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## macmiller (Jul 23, 2007)

You could use a halftone base to use the shirt as part of the design. I've only done a few CMYK jobs, and only one that needed a white base.







I used halftones to let the print fade into the shirt on the globe. It worked really well.


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## becki4 (Oct 2, 2007)

Ok, it's going on a black shirt so there's every need for a white underbase.

The white base is achieved by converting the image into Greyscale and inverting (it's not a solid outline), what i'm basically asking is how should this be output as a spot colour (we use settings 45 degress / dot) or in another way?

Thanks


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## PatFinn (Jan 13, 2010)

i wouldnt do 4 color process on darks.. in my opinion you wil get better results with simulated process. 

as for angles use 22.5 deg for everything!


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## becki4 (Oct 2, 2007)

Are simulated and index the same thing right?


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## jsf (Aug 4, 2009)

becki4 said:


> Are simulated and index the same thing right?


Simulated uses halftones to get much of the gradient details and index uses dots of squares of the same sizes (dithered effect). 

Technical process in preparation of your artwork either process defines the appropriate major colors (defined as channels including underbase and highlight), the more colors you specify the more output detail you will get.


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## becki4 (Oct 2, 2007)

Any decent tutorials on Simulated jobs about? Thanks


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## jsf (Aug 4, 2009)

becki4 said:


> Any decent tutorials on Simulated jobs about? Thanks


Doing Simulated manually is a very tricky-tedious job, this is the hard way. "Photoshop 7.0 for Screen Printing - Google Books"

But you may consider doing it the fast way around (like most printers do) by adding plugins to PS to automate the process -- Quikseps, T-seps, Spot Color, Willflex and the like.


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## becki4 (Oct 2, 2007)

I'd happily use plugins but I'm on a mac and they're never easy to get hold of... (without paying)


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## pukingdeserthobo (Jun 3, 2008)

what do you mean without paying?


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## becki4 (Oct 2, 2007)

Surely those plugins cost money right?


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## jsf (Aug 4, 2009)

Well, these things are considered investment that is why you have to pay for it.  or n'theless, learn the hard way.

Goodluck.


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## becki4 (Oct 2, 2007)

Ok, which ones are recommended, i've heard T-seps isn't very good.

Will they handle both Simulated and Index?


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## jsf (Aug 4, 2009)

becki4 said:


> Ok, which ones are recommended, i've heard T-seps isn't very good.
> 
> Will they handle both Simulated and Index?


Now that I cannot comment... .

But many people in TSF has already asked the same:

http://www.t-shirtforums.com/screen-printing/t5564.html
http://www.t-shirtforums.com/graphics-design-help/t16567.html
http://www.t-shirtforums.com/asia/t93070.html
http://www.t-shirtforums.com/screen-printing/t113087.html


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## becki4 (Oct 2, 2007)

Thanks i'll check out those threads.


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## RatedOG (Jan 26, 2010)

Not sure that this would be the correct method to underbase the cmyk on darks, but could work. 

Print one transparency with all the channels selected. I would think this would put white under each halftone dot for each color. Might need to create a little choke for the white also.


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## LitPrinter (Apr 25, 2008)

Better results you will get with halftoned underbase. It is simple wat to make this underbase. Just change your image in photoshop from rgb (or cmyk) to grayscale and then invert it. Then you can a little bit play with levels or curves. Main thing for this underbase is that, than you willl get solid underbasing for most light colors and almost no underbase for most dark colors. Besides, everithing depends from desing, sometimes it is necessary print solid underbase without halftoning.
Sorry for my english, it is not my native language


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