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Mark Ross
07-21-2009, 9:49 AM
So we use our Epilog 36EXT strictly for cutting at work and we tie it up most days for at least the full first shift. However, due to the economy, they would like to be able to "offer" other items to our customers (we are not retail, strictly commercial, not in the awards market either).

So I went to Lowes and bought "granite" tiles. Now these tiles are called "natural stone" and since they came from China...let's see China...lead paint in kids toys, Melamine in baby formula, Radioactive stinky drywall....I wouldn't be surprised if this WASN'T Granite or anything close.

I will attach the pictures in a seperate post of the tile.

I would like to thank everyone here for posting, as it makes is so much easier to have successful attempts straight out of the gate. The resolution on the tile is only 150dpi, when I tried to reproduce the same tile at 300 DPI, the picture washed out really badly on the tile.

Does anyone here buy 12X12 tiles from places like Lowe's, Home Depot, or Menards? I am just wondering if granite should say granite on the box...

Also if anyone can offer a link to a company that sells laserable stone that also custom cuts and shapes various sizes please let me know. Thanks!

Mark Ross
07-21-2009, 9:56 AM
These are the shots from the box of "granite" tiles we bought. I am thinking this is not granite...might be okay for doing logos and stuff on, but not pictures.

matt heinzel
07-21-2009, 10:06 AM
I might be crazy, but what is wrong with the photo? From your image it looks pretty good.

Dee Gallo
07-21-2009, 10:45 AM
You're not crazy, Matt!

Mark - That looks fine, in fact excellent for your first one, in fact many people haven't gotten such good results YET after many tries.

I think your photo prep could use some work, to make the subject stand out better from the background, or you could more picky about what photos you start with. But that's a really good job!

cheers, dee

Dan Hintz
07-21-2009, 11:26 AM
That's granite...

Mark Ross
07-21-2009, 12:57 PM
Thanks for the feedback, I used the "gold" method I found in one of the forums. Thanks for letting me know that is granite, I wasn't sure. I guess it would look a little better on pure black granite.

I bought that from Lowe's, the Menard's in our area doesn't sell granite but have plenty of various colored marbles. Do some color marbles work better than others? I bought a couple of pieces to play around with (only a couple of bucks a tile!).

The photo of the tile looks better than the original (then again, I'm an engineer and a bit (haha, more like BIT) of a perfectionist. I am just wondering if most people engrave granite at 300 dpi or if that resolution is too high (I might have the power set too high, I haven't looked at the piece under a microscope yet).

We have various software here and Corel Photopaint has some features where they show you things as a graph, like contrast enhancement, and I am thinking that maybe those graphs have a sweet spot and if you adjust various settings and always get your graphs to look about the same, it might help because working in greyscale everything is a bit subjective. If I do find out more along those lines I will be sure to post it.

Tom Bull
07-21-2009, 1:32 PM
Go to coreldrawpro.com and find the June 2007 and July 2007 archives for a full lesson on engraving granite and marble.

Dee Gallo
07-21-2009, 2:06 PM
(I might have the power set too high, I haven't looked at the piece under a microscope yet).

You inspect your work with a microscope? You are WAY more picky than the average person!;)

I've gotten absolute black granite from Home Depot - looks just like yours.

cheers, dee

Jack Harper
07-21-2009, 2:47 PM
You inspect your work with a microscope? You are WAY more picky than the average person!;)

I've gotten absolute black granite from Home Depot - looks just like yours.

cheers, dee

I inspect our engraving under a digital microscope all the time. This really takes the subjective guess work out of the process and lets you determine the precise resolution very quickly. I can even take pictures with the microscope and save for future comparisons.

Glinda Fabok
07-21-2009, 3:08 PM
Mark, absolute black is the name of the granite you need to look for otherwise a lot of colored flecks in them. also I make it a habit to actually open the box and look at them because some are in no way absolute black. A great place to shop for different media to use is Lasersketch.com They have great stuff...Loved the picture, by the way..

Mark Ross
07-21-2009, 4:51 PM
I was able to figure out our 45W epilog ain't gonna be replacing sandblaster technology anytime soon...:D

I gotta go get another box of tiles and figure out if I try to do 300DPI if I need to reduce power. It may be that the "finish" on that granite isn't the greatest and the laser? might be blowing chunks of it off?

Either way, I think I figured out how to tile the kids room and give them

1. Hopscotch
2. Shuffle Board
3. REALLY big checkers and chess...

Now I just have to figure out the proper "untruths" for the bossman so when he walks by the laser and asks me what is this, I will have a canned answer for him!:D

Tim Bateson
07-21-2009, 6:12 PM
Mark, absolute black is the name of the granite you need to look for otherwise a lot of colored flecks in them. also I make it a habit to actually open the box and look at them because some are in no way absolute black. A great place to shop for different media to use is Lasersketch.com They have great stuff...Loved the picture, by the way..

I don't believe the "marble" they sell is the real stuff. Never tried their granite.

Miguel Pinho
07-21-2009, 6:51 PM
Hello everybody...

I work for a long time on laser engraving in stone. From my experience the best granite to engrave is called Indian Black, and Negro absoluto (absolute black). In Portugal i buy this granites for 55€ to 70€ m2, slabs of 2mm thickness.
By the way...that stone you engrave is also very good for laser, they come from china..here we pay 38€ m2, in tiles of 040 x 40 x 1,5 cm.
Your engraving is very good for a first time, but you have to try it without less brightness.
Use photograv, is much more better than Photoshop to engrave.
Dont forget to use the sharpen tool and, unsharpen mask tools in corelpaint after you change the picture to 8bit greyscale.

Regards from Portugal

Dan Hintz
07-22-2009, 11:30 AM
Thanks for letting me know that is granite, I wasn't sure. I guess it would look a little better on pure black granite.
Mark,

If you're not completely satisfied with the look, try absolute black marble. It holds more detail as you're bleaching the marble (use in 3D mode with an 8-bit grayscale image) rather than blasting out chunks of the granite with a two-tone image.

Belinda Barfield
07-22-2009, 5:04 PM
Mark,

If you're not completely satisfied with the look, try absolute black marble. It holds more detail as you're bleaching the marble (use in 3D mode with an 8-bit grayscale image) rather than blasting out chunks of the granite with a two-tone image.

I would like to, respectfully, disagree with you on a point here Dan. In both cases, marble or granite, all you are doing is removing the surface polish. You can't "bleach" marble, unless you are removing the dye that is frequently used to deepen the color.

Absolute Black granite is actually basalt. Some of the "crystals" in the stone are larger than others and fracture when lasered. Larger the crystal, larger the pit created, which accounts for the uneven engraving often seen with granite.

David Arana
07-22-2009, 9:59 PM
After reading all these posts today. I went to lowes and purchased me 2 12x12 all black marble tiles. I did a little research on the forums and read that marble is fairly easy to get high quality images on. Any special filters I should use on photoshop? Should I set my brightness a little higher on the images? This will be the first thing I do tommorow. Wish me luck!

Tim Bateson
07-22-2009, 10:34 PM
Check past posts. Frank has some good technical advice from a post about 6 months ago.

Steven Wallace
07-23-2009, 1:22 AM
I have been asked to quote a 3' x 3' piece using 12"x12" tiles. Can anyone give me a quick tutorial on how I do this using corel x3 and my epilog

Chris J Drew
07-23-2009, 8:25 AM
Tiling graphics tutorial:
http://www.epiloglaser.com/tiling_graphics.htm
( Tutorial is for Corel12, but should suffice )
Or this:
http://www.identify.co.uk/Pdf/Whitepapers/murals_multiple_tiles.pdf

If you're engraving a photograph, convert to 1-bit with "Stucki" dithering in CorelDraw, rather than sending a greyscale to the laser.
( Always convert after resizing )
In CorelDraw: Bitmaps/Mode/Black and White(1-bit)...
This process bypasses the dithering in the Epilog driver and gives you more control over the result than the Epilog driver's own dithering, as there's a slider to tweak & a preview window.

Dan Hintz
07-23-2009, 11:41 AM
I would like to, respectfully, disagree with you on a point here Dan.
No need to be respectful, Belinda... I don't mind if people disagree with me :)

I'll back up a bit and say I personally have found marble to hold a much higher resolution than granite. The reasoning behind it is fairly simple; With marble, every lasered point can hold a grayscale value, but with granite, that grayscale needs to be emulated over a larger area through the dithering process (which, as we all know, forces each lasered point to be either white or black). Point for point, I can get a higher resolution if each point can hold a 16-value grayscale rather than the same color being emulated through multiple black/white dots over a wider area.

Belinda Barfield
07-23-2009, 11:49 AM
No need to be respectful, Belinda... I don't mind if people disagree with me :)

I'll back up a bit and say I personally have found marble to hold a much higher resolution than granite. The reasoning behind it is fairly simple; With marble, every lasered point can hold a grayscale value, but with granite, that grayscale needs to be emulated over a larger area through the dithering process (which, as we all know, forces each lasered point to be either white or black). Point for point, I can get a higher resolution if each point can hold a 16-value grayscale rather than the same color being emulated through multiple black/white dots over a wider area.

Agreed, results with marble are much better than those that can be achieved with granite. I'd never argue that point.

Mark Ross
07-23-2009, 2:47 PM
So I meandered down to Menard's and they have marble floor tile, 12 X 12 just like Lowe's has granite...so I bought a couple pieces.

Ran it at 100 percent power on an Epilog 36EXT 45 watt unit...Can't really see anything! Now...the marble I bought, one piece is pink, the other is salt and pepper, but I really can't see anything.

Did I buy the wrong stuff or do I have to run the file several times to get results?:confused:

Dan Hintz
07-24-2009, 11:19 AM
Mark,

When you say you "don't see anything", do you mean the entire picture is washed out, or it looks like the tile has been untouched?

Mark Ross
07-24-2009, 3:47 PM
The laser etched it, I can feel it, but there is no really visible definition. I am wondering with a 45 Watt laser if I should be doing several passes to get marble to act like the granite I was successful with?

I dunno...

Steven Wallace
07-24-2009, 5:01 PM
Only kidding, I have a 35 watt mini 18 and you should not have to run a second pass to see something.

kyna cass
07-25-2009, 2:58 AM
I have used this Home Depot Tile and have had much success with it. Ive done dog portraits and a portrait of my father. The detail was great ! The only worry I have with this tile are the flecks and sometimes a vein will appear after the tile has been engraved . Obviously it was already there but it doesnt show until after the engraving is done. (its only happened once though ) I spent a solid week trying to perfect the best settings for this tile and this was the best for me with my 30w Versa Laser
First and important I adjusted the Gamma and Tone Curve to brighten the photo (mine needed to be brighter)
Then Power was adjusted to %50
Speed adjusted to %42
DPI 250

300 DPI washed out the engraving slightly too much
Hope this helps

kyna cass
07-25-2009, 2:59 AM
I have used this Home Depot Tile and have had much success with it. Ive done dog portraits and a portrait of my father. The detail was great ! The only worry I have with this tile are the flecks and sometimes a vein will appear after the tile has been engraved . Obviously it was already there but it doesnt show until after the engraving is done. (its only happened once though ) I spent a solid week trying to perfect the best settings for this tile and this was the best for me with my 30w Versa Laser
First and important I adjusted the Gamma and Tone Curve to brighten the photo (mine needed to be brighter)
Then Power was adjusted to %50
Speed adjusted to %42
DPI 250

300 DPI washed out the engraving slightly too much
Hope this helps

Tom Bull
07-26-2009, 5:38 PM
I have had pm from people having hard time finding the articles on how to engrave marble and granite. Here are direct links:

http://www.coreldrawpro.com/library/CP-607.pdf
and then go to page 14. That is the granite article.

http://www.coreldrawpro.com/library/CP-707.pdf
go to page 15 for the marble article.

This guy does great work and is really in depth with his explanations not only on what works, but why.

Mark Ross
07-27-2009, 8:58 AM
Well, playing around with scrap cedar wood, I have the feeling that using wood and a laser to make photographs is a lot easier, it pretty much uses the same techniques.

What I did and think I will continue to do is make several lower power passes. If I use too much power, the piece is scrap, if I use too little I can just make a second or third or fourth pass as needed. At least until I get a feel for all the various different woods out there.

Looks like I need to make another trip to Lowe's and Menards for some wood this time...:)

Tom Bull
07-27-2009, 9:12 AM
There is a wood called okume (aka african mahogony) that works great as well as spanish cedar. Don't give up on granite or marble until you have used the methods on my post just above this one. Finding that info was a turning point for me, and now most of the custom work I do is on granite.

Mark Ross
07-27-2009, 9:37 AM
Thanks Tom,

I am just not sure I can convince my company to spend money on software to photographs when we don't have any orders for it (putting the cart before the horse type of thing).

Of course from the sounds of it Photograv is extremely easy to use, so when they tell me to go ahead and buy it because we got some big order, the learning curve shouldn't be very steep.

Tom Bull
07-27-2009, 3:06 PM
I see what you mean. There is still a lot of good stuff about dpi, etc in the articles anyway