View Full Version : Introduction with a question about Dithering

Dale Lovell
07-22-2011, 8:25 AM
Greetings all, I have followed this forum for quite a while now and must say that this is generally the first place I visit in the morning :). Everyone on here has been a big help for me and I thank you. Back in May I purchased a 50W Helix and have it setup in my shop. I am impressed with the quality of the images it can produce.

Enough said, so now my question.

When setting up a job and using the Gold process, or Photograv we use dithering. Ok now it's dithered. Now when I go to print I get another choice for dithering. What's up with that? Am I dithering the Dither?


Rodne Gold
07-22-2011, 8:37 AM
You shouldnt print the output of photgrav or the gold method as a greyscale or in any form that wants to dither , its only black dots , you need to print it the same as you would do a black filled vector type engraving

Dale Lovell
07-22-2011, 9:13 AM
Thank you, Am I correct in saying that the image will only be dithered if its Greyscaled and If I dither it myself and convert to a 2 color bitmap the epilog driver will not dither?

Larry Bratton
07-22-2011, 9:58 AM
Welcome to the forum. The subject of dithering has been discussed here in depth. If you will just do a search on dithering in the search box, you will be blessed with a huge amount of information. You can start by reading this thread http://www.sawmillcreek.org/showthread.php?161219-A-couple-of-questions-re-the-Gold-Method
and another http://www.sawmillcreek.org/showthread.php?141147-Photograv-Dithers..then-Epilog-uses-Standard-in-addition..wondering-about-effect&p=1433404

Bill Cunningham
07-23-2011, 9:30 PM
Dale; Once you have run it through photograv, or the gold method, you just engrave it.. Don't change any settings. On my Epilog, the clipart setting will auto dither if it's a greyscale, or just engrave if it see's only black. Black is all it should see from a photograv (or Eqiv.) file.. Just never change the size of the image after it's been converted to a two bit file, or it won't engrave properly.. Make all your size adjustments 'before' you run it through photograv (or equiv.), and engrave in only multiples of the original dpi .. i.e. don't engrave a 300 dpi image at 400 dpi, but it can be done at 300/600/1200 dpi..

Dale Lovell
07-24-2011, 4:14 PM
Thank you all. If I would have just paid attention to the manual I would have understood it. I did read the manual before I started using the machine, but not much of it sank in. I ran through it all again and have found a wealth of information that makes sense now that I'm actually using it.

Frank Corker
07-24-2011, 4:47 PM
Just to clarify. Leave the image dithering as standard when you go to print through the Epilog module. It will be fine. With Photgrav 2.1 the original image has to be 8bit black and white, with Photograv 3.0 it can be colour as is with the Gold method.

Dee Gallo
07-24-2011, 4:48 PM
I ran through it all again and have found a wealth of information that makes sense now that I'm actually using it.

Welcome to the Creek, Dale! You have discovered the secret to operating a laser: there is no substitute for experience. After you've created lots of scraps and samples, you'll understand what you're doing and it does actually all make sense eventually. That is, until you discover you want to try a new substrate or technique, then the cycle begins again! Too much fun :D

cheers, dee