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need dots for silk-screen printing...

Posted: Mon Feb 21, 2005 3:36 am
by La Dima
I like paper-base silk-sreen printing & i never make gradation effect to screen print coz that is very difficult to screen print since i'am using a simple tools, so i need to change the image into dots first. What i would like to ask are ;

How to change a picture with gradation into dots which resembles a picture in photoshop, the dots has to be fade from a full solid dots into fewer & fewer dots in the edge of the image so it will make a gradation-like effect. How can i do that ?
Is there a filter like that ?

I am using photoshop 7, Thanks.....
Sorry my english is bad...... :D

Posted: Tue Mar 01, 2005 1:18 am
by Musicman
Firstly, excuse me if I'm misinterpretting your dilemma. But, if you are planning on silk-screening, and are printing images out in seperate colors via channel seperations, a post script driver for your printer should allow you to set the half tones. That is if it's a Laser Jet printer, if it's an ink jet printer, you will need to purchase a RIP program (raster image processer?) to do the half tone conversion before it can print them.
Within the post script dialogue in the printer settings, you should be able to control the dot gain, type of dot (circle, eliptical, etc...), calibration marks, etc...
My experience in silk screening comes from years in the textile printing industry, so I don't know the settings for printing to paper, but, I don't think the dot gain is such an issue as in textiles.
I hope you have a laser jet, because then you are just a post script driver away from creating half tone dots. If you are on an ink jet, the RIP programs are expensive, at least the ones I used. Though the calibration marks are perfect when using an ink jet, and they tend to be off at press when using a Laser Jet, though, you can easily run the blank vellum through the printer to pre shrink it to slightly reduce the problem.
Well, I hope that helps, if not, I apologize if I misinterpretted your problem.


Posted: Tue Mar 01, 2005 2:48 am
by OnceNew

Posted: Tue Mar 08, 2005 3:41 pm
by dvector
In any version of Photoshop:-
change mode to greyscale, then
change mode to bitmap
set output to 600pix/inch (for 600dpi laser for example)

Set FREQUENCY to 53 lines/inch ( 10 very coarse, 150 would be high detail)

Angle 45 degrees

Shape ROUND (sometimes other shaped dots work better for certain printers)
now print your image!! great greyscale from b/w printer!!. Its important though not to resize the image and you must print at actual size to match printer resolution. ((Also will look bad onscreen at certain zoom levels. 25% looks good and will show the overall results of the image))

best regards /David