[MarkGV]

I am printing the attached red grunge letter onto a black shirt. Just how should I choke the under base white or should I just under base in red and not choke? I have tried to stroke the top red design 2 points but it alters the small grunge lines to much. I can offset the under base but it is difficult with all the tiny areas. I am using Illustrator. Any ideas on how to handle this.

Thank you!

 

[red514]

In my opinion it is better to use a chocked underbase rather then doubling the image (wether you print the same screen twice or different screens). Using a chocked underbase will help reduce dot gain and preserve more of the fine details

when you chock the design in illustrator, you will loose some of the finer details on the under base screen but the top screen will still have it. where those finer details fall on to the shirt fabric without the under base, the color will be a bit darker but the detail will still be there. This technique can even add to the look of a grunge print.

 

[UltraSeps]

Photoshop is your friend with things such as this.


Bring the image into Photoshop and make sure its RGB, 300 dpi minimum.

Duplicate the Red Channel of the RGB's.

Using Curves make certain the duplicate channel reads 100% solid using the Info Palette. Use a Curve that doesn't want to start closing in the fine details. Usually a small "S Curve".

Turn that duplicate into a Spot Channel - White Ink - 100% Solidity
.
Duplicate the white ink channel and make it Red Ink - 10% Solidity.

Make a new Spot Channel - Black Ink and fill with solid Black. Place this above the White Channel. This is the shirt color.

Select the White Channel and load as a Selection.

Make sure the Color Swatch in the tools palette has White on top, Black on the bottom.

Select Stroke - Center - 3 - 4 Pixels. (experiment with the number) Click OK.

Doing so will choke the white base.

Choke the base more than you would normally do as there's many small details in the art and these will easily fill up.

This process is actually quite easy. It just sounds difficult.

The image below is just to give you a visual of the above and isn't super accurate since I only had a low res jpg.

 

[dennyk671]

If it's a small run I would just do a double hit with the high opacity red.

But if I want to add and underbase I would do it in photoshop instead of illustrator. Because the design is a little sensitive to the choke if done in illustrator I would just open the vector file in photoshop. Doing it in photoshop keeps the choke more even.

What I usually do is open the ai or eps file in photoshop. When the options box shows up I set the resolution at 600 to 900 with anti aliasing off. It does create a bigger file but it will look like vector quality when it is output to film. When you use your magic wand to make your choke make sure anti aliasing is off. I usually do a choke of about 3 to 4 pixels.

Doing it like this at my work saves me a lot of time on certain vector files. And no one can tell if it was done in photoshop.