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| masonmayhem |
 Posted: Tue Feb 20, 2007 4:27 pm |
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Joined: 28 Oct 2004
Posts: 1376
Location: Redneck Riviera, AB
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when printing halftones, whats the best settings to have on my printer? right now the printer (when i print halftones) is set to:
Screening Technology = Standard Default
Frequency = 80
Angle = 45
or does it even matter?
if any of this even makes sense. sorta did in my head.
i just notice that i have to burn a few screens to get the halftones to come out relatively nice. usually it just washes out like it was a solid graphic. |
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| Fool's Gold |
| Posted: Tue Feb 20, 2007 6:25 pm |
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Joined: 10 Mar 2005
Posts: 284
Location: Ontario Canada
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dont use 45. Use 22.5 degrees. Mesh is stretched 90 degrees to the frame, you don't want a number that will divide evenly into 90 because it can cause moire. Moire = a strange interference in halftones caused by them running at strange angles to the mesh. Ever scanned a picture from the newspaper and noticed the strange patterns? that's Moire. It gets more complicated when you start mixing many halftones (each needs to be set a certain % apart from each other otherwise they start to interfere with each other, I don't have the formulas in front of me but can get you angles and such) But, mixing haltones at the correct angles will creat 'rosettes' which is what creates those continuous tones seen in magazines.
your frequency is the LPI. 80 is way too high, way too high (unless you are using a 450 or egyptian cotton screen)
Take your mesh count and divide by 4.25 or 4.5. that will give you the LPI that you can hold on that screen. So say you have a photo and only a 200 mesh screen. 200/4,5 = 44.5. So you can technically hold a 44 LPI halftone dot on that screen. Now you will probably not expose the very small 1%-10% dots, and will mash out the 90%-100% open areas. So consider that when you are selecting your gradient areas etc. This is when having good film, good emulsion, a good exposure unit and really good presure between the mesh and film is of upmost importance. Any weak spots in your process will cause more problems later on. |
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| masonmayhem |
| Posted: Tue Feb 20, 2007 8:16 pm |
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Joined: 28 Oct 2004
Posts: 1376
Location: Redneck Riviera, AB
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wow.
thank you. i had no idea it would be that technical. |
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| Fool's Gold |
| Posted: Tue Feb 20, 2007 9:25 pm |
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Joined: 10 Mar 2005
Posts: 284
Location: Ontario Canada
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| I like the science behind it. Plus I have printed enough stuff for people that I have run into alot of different problems and I read a lot of technical articles too. |
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IRONCLAD GRAPHICS: Custom screen printed posters, apparel and stickers. |
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| badgoldfish |
| Posted: Wed Feb 21, 2007 12:11 pm |
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Joined: 20 Sep 2005
Posts: 406
Location: kalamazoo-michigan
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| sheltered |
| Posted: Sat Feb 24, 2007 3:21 pm |
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Joined: 16 Sep 2005
Posts: 86
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Fools Gold is exactly correct
I simplifiy it by saying when you need to screen (either print or scan) a screen your need to pay attention to the angles.
http://www.mathematik.com/Moire/ |
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