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Discussion Starter #1
I am having a problem with my halftone print outs. I am doing a single color photo image in haltones. At first i printed it with the settings 300 output 50 freq 45 angle and it came out ok but i wanted smaller halftones so then i changed the frequeny to 100 and it came out a lot better so i burned a screen and printed a few shirts. I saw some parts I wanted to touch up so I did that then tried to reprint the transparnecy again with the exact same settings but now my halftones have a plaid pattern to them. Why would it print like that the second time around when the first time was perfect? I tried it a couple more times with the same result. I dont want to keep wasting ink and transparency for this print.
Any suggestions?
I am using photoshop cs2
epson 1400

ill see if i can attach a photo of what im talkign about.
 

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First off, don't go higher than 55lpi, and that's for a 305 screen, not lower. If your halftones are too fine, you'll wash out dots (emulsion, not ink), and ink can't get through holes (your halftone dots...), partially because the're too small to be washed out, and then some more because the ink is too thick to go through the tiny holes.
Secondly, go for a MUCH higher resolution for your halftones (or are you using a RIP? It's not quite clear...). Go to 1000 or so. Rule of thumb: 16* your haftone line. In your case this would be 16*55=880dpi. If you go lower, you lose color accuracy which can lead to banding. So, in short, your halftone line count is too high, and your res is too low.
What you did before to make it look okay is a mystery, and it will probably remain a mystery.

Lastly, remember: Bigger dots print more accurately, smaller dots are less visible. So, you want to go as small as possible, but not lose the accuracy! For manual press screen printing, you're talking about 55lpi max. SOme use 60, but it gets real hairy there...
 

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Discussion Starter #4
Thanks for your responses
I found the problem... i was running low on ink so the printer goes into ink saver mode (from what the epson guy told me) i put in new ink and tada great prints again.
 

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If you have a 300dpi image and try to make halftones of 100lpi, that means each halftone comprises of a cell 3x3 dots. You can have any number of dots from 0 to 9. That means if you have a vignette/gradient from 0-100% it will have 10 bands of colour and look horrible.
If you have a 50lpi halftone, you have 6x6 dot cells and 36 bands of colour.
Print that on a RIP and you will have something like 800 bands, listen to DDSol.
 
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