Photos on Marble w/ Mercury 25 watt

[Debra Thayer]

I recently purchased a Mercury 25 watt laer engraver and I am having quite a bit of trouble with photos on marble. First of all, I do a lot of Dogos (a mostly white dog), which is hard to begin with. I used LaserSketches 5x7 marble (which they say is a hard marble, unlike their smaller sizes). I ran at 500 dpi @ 100 sp, 84 power. Looks great. Went to a smaller piece of marble, different pic of same breed, (3.8 x 3.8, which according to them is a softer marble). Looks really bad. Tried 300 dpi, 500 dpi. I am quite new, so I have no idea what P/S settings to even start at!! Do I need to change the ppi in the print setting or leave auto? Please help!!!!!!

Thanks!
Debra

[Barbara Sample]

Hi Debra,
I just read your post, and am glad to see that you are having success with the marble photo's. When you said you did the smaller one with not a lot of success, it's not you it's the marble. For some reason, the smaller stuff that they have engrave with a greyish look to them. I ordered some of their Opaque white to paint onto it, and it works really nice. It makes a grey photo nice and white. Call Jim, he will help you out. He is very nice, and good about helping you.
I am only ordering the new marble that he has, because it engraves very nicely, but unfortunately, he does not have it in the smaller sizes. Just buy the paint and try that, it looks thick, but once it's applied with a paper towel and wiped off, it looks very nice.
Good Luck, I hope this helps you.
Barbara
RGile Engravers

[Debra Thayer]

Actually, on the small marble, the image is completely washed out, no contrast, like I ran a grinding wheel over the image area. Unfortunately, I have people who want the pictures on the small marble. Like I said, I am brand new at this, I have no idea where to start w/ settings when it is turning out like that. I have tried 300 dpi with many settings, 500 dpi....no luck. Maybe it is the picture...too white with no contrast. Can this be corrected? Thanks!

[Debra Thayer]

I think I this is the link to the pic I am working on http://www.sawmillcreek.org/attachment.php?attachmentid=25155&stc=1&d=1130287689

I have reduced the dpi. for purposes of this forom. I have tried everything to get this right.....I am working with marble from Laserbits...THANKS!
Debra

[Mark Plotkin]

Debra,

I have been using the marble tiles from Laserbits with great sucess. I have tried lots of setting and from my experience can share the following:
I do not run any job over 300dpi they "washout"
I do use photograv with the blackmarble prm.
I run the jobs at 35power and 75speed on an epilog mini 45w
I have used all sizes of tiles from Laserbits with great results.

Hope this helps

[Keith Outten]

Debra,

There can be a significant difference in black marble, the best quality has been tile from China. Lately both of our sources we purchase tile from have shipped us terrible quality tiles, at the preset time we don't have a reliable source to purchase tiles that are suitable for engraving purposes.

Possibly you can find someone in your local area who owns a tile saw and have your larger tiles cut to suit the job. Just a suggestion.

[Debra Thayer]

I have tried 300 dpi, still washes out. I am mainly having troublw with picture I posted above. If you could take a look at it I would really appreciate it!
Debra

[Shaddy Dedmore]

Washed out usually means too muc power. What I would do is set your photo up like you want it, then make a smaller rectang over some part of the picture, then use Power Clip to "crop" the picture to that rectangle. (if you're using Corel, that is). The reason for not just resizing the picture is that then you change the size, you change the sampling and then you won't have a good idea of that the setting will look like on the actual sized picture. Now, move that rectangle/picture around a sample pice and find good settings.

Start fast/low power because you can always do 2 passes to make it darker (well, lighter). As you found out, it will never get white like some marble can though. And don't get above 300dpi like others have said (Laser Sketch marble doesn't like that). Above 300 and you will lose all detail.

Just some tips to help you find your own settings, even numbers right from Laser Sketch will need to be tweaked because one 25w laser will be different than another 25w, even from the same manufacturer.

Shaddy

[Debra Thayer]

Thanks Shaddy, I just did the pic again, in to Photograve @ 300, engraved at 300 sp95, P60 and it turned out great. I did have the power way too low I think and it was really bad. I engraved this on a 3.8 x 3.8 piece of marble. What is the best way to resize this same pic to a 5x7 without losing resolution? Thanks!
Debra

[Shaddy Dedmore]

You have to resize the original photo and then photograv again. Photograv makes it into a series of dots, if you resize after photograving, all you are doing is making the same dots bigger or smaller. So always keep your original photo in case you need do just what you're talking about. That was why I suggested using Power Clip. You can make your picture a 5x7 & 300 DPI in whatever Photo program you are using (Paint, Photoshop, Paint Shop Pro), then use Photograv. Then if you need to make it smaller for practicing, just power clip a section and you don't have to worry about resize issues. Pick a section like a face (for detail) or a section that has lights and darks (to make sure both look good at those settings). This method just saves you from needing intermediate photo's that probably won't match your actual end-result photo anyway. I make a square about 2" across and 1" tall, it's usually enough to tell if the setting are good. Then I laser it, and move it over and laser it again at different setting, until i get it right. My scrap piece usually ends up full, and I try and use a sharpie and write my setting on the etchings.

Let me know if I was confusing and I'll try a different approach. I usually throw too many words out there, I'm not very efficient with my descriptions.

Shaddy

[Debra Thayer]

I do understand, although I am not very familiar w/ Power Clip. Would my p/s settings vary from pic to pic? Most of my customers e-mail the pics to me, I rarely have the originals.
Debra

[Joe Pelonio]

One other suggestion, if the customer has the photo as a jpg and has the ability to change it to tif before sending it will end up working better. Better yet have them scan the original to a tif. The file will be a lot larger, but jpgs lose resolution every time they are saved, being compressed up to 90%. Great for the internet but not so good for engraving. Another good format is pdf though I find with Corel 12 that I have to have one photo per pdf file or I cannot separate them.

[Harry Radaza]

just wondering how much are you guys getting these tiles from china for ?

Coz if it helps, black granite tiles here in the philippines engrave really well and they are pretty cheap. Maybe in bulk even with shipping might come out still cheaper for you guys in the US ?