PDA

View Full Version : Photographs on black marble??



mike berry
12-12-2010, 12:10 PM
After many, many hours trying to figure out how to remove the background from a photograph, we have finally figured it out thanks to a video on Roy Brewer's site.....is there much he doesn't know?!

We are using Corel Draw X5 by the way.

We have a New Hermes LS100 30 watt laser and looking for tips and or suggestions on how to successfully engrave a photograph on black marble. (the New Hermes books says 500 DPI, and I know very little, but I do not think that's right)

There seems to be many variations on the DPI to use as well as the power/speed settings.

Any input and suggestions would be most welcomed!

Keith Outten
12-12-2010, 1:09 PM
Mike,

I can't address the photo editing issue but I invite you to try my tip for whiter engraving on black marble. Use a little Armour All on your black marble time before you engrave, try it on a piece of scrap and see what you think.
.

Larry Bratton
12-12-2010, 1:37 PM
Mike:
You should set your laser to engrave at the dpi of the photograph. Photographs of poor quality, such as something downloaded from the internet that is 72dpi or 96dpi are going to give poor results. Usually 200 to 300 dpi is what you need. Power and speed settings for marble are low speed, high power. If granite, the reverse is true, high speed, medium power. You can try 15 speed-100 power as a start (that is recommended setting for an Epilog 30-35 watt @300 dpi. for marble. Here is a YouTube video that is a pretty good tutorial on photo prep for black granite or marble in Corel. http://www.youtube.com/watch?v=ZubRDUrg_7k&feature=related

Donna Bihm
12-12-2010, 3:57 PM
Yea, I thought I was crazy the first time I did granite. Amazing all the little steps you need to do to get it right. Not sure if this really makes a difference, but I've also noticed that the dpi in the photo processing software (I use PhotoGrav) can be different than what you are processing in Corel. I usually double check that and change the PhotoGrav to the same dpi as what I am working with in Corel.

Larry Bratton
12-12-2010, 8:59 PM
Donna, that doesn't matter. What matters is what dpi the photo was created at. Photograv likes 300dpi. If you scan a photo, scan it at the resolution you intend to engrave it at. The resolution your working at in Corel is not relevant to this process. If you process a photo through Photograv at 300dpi, set your engraver to run it at 300dpi. However, if you will work with your photos and learn how to process them in Corel, you will use the Photograv CD for a coaster.
It is easy to overwhelm granite with too much power. With my 40 watt Epilog, I usually run granite at 40 power/ 100s. I always fill granite to whiten the mark. You simply get different results on marble than you do granite. They are two totally different materials. Remember though, they are both natural materials and they can't be relied on to be consistent.

mike berry
12-12-2010, 9:16 PM
Larry,

I am already there withe Photograv software.....I tried to get assistance form them, might of just walked out in front of traffic, it would of been less painful. To say the customer service was horrible just doesn't even begin to scratch the surface........

Larry Bratton
12-12-2010, 9:35 PM
Mike:
I bought both V2 and 3. This was when I was a real newbie and I thought that was what everyone did. It's OK, but I like the experience of being able to turn out a photo using MY skill and not some canned program doing it for me. I can honestly say that I get better results with my methodology than with Photograv. Had I know then, what I know now, I would have saved my money. I can't speak for their customer service because I don't think I ever had any direct dealings with them. Many people in the forum use methodology other than the off the shelf programs. Rodne Gold for one. If you have Photoshop you can do a search on here for the Gold Method that he developed. Photograv can't do anything toward processing a photograph that you can't do. Some say, however, Photograv is very good for processing clipart for engraving, I can't speak to that either way.

Ross Moshinsky
12-13-2010, 12:34 AM
Download Universal Laser One Touch software. 100x better than Photograv. If you plan on doing photos on the cheap, this is the way to go. Very decent results with minimal fiddling.

I think there is a lot of confusion when talking about DPI. DPI is really a unit only discussed when scanning or printing. Once the image is in your computer, DPI ceases to exist. Everything turns into pixels per inch (ppi). The two are not the same unit at all. You will never hear someone mention DPI when talking about a digital camera. It's because digital files don't have dots, they have pixles. That is where Megapixel comes from. So, if you want to find engravable files off the internet the most important thing to search for is resolution and clarity. High resolution images are not always clear, and clear images are not always high resolution. When you scan at a high DPI you are attempting to create a clear high resolution image.

As for lasering resolution, it depends on how you prep the photo. If you do not create accentuated halftones within the image, you need to engrave at a low DPI to create them. If you process the photo where the halftones are accentuated, you can engrave at the typical 500-600dpi. Print a photo on your printer at 300 and 600dpi and you will see what I mean.

mike berry
12-13-2010, 7:16 AM
I did download the Universal 1 touch and you are right, alot better even for a newbie like me! Ed Williams at Universal is awesome to talk with, a wealth of knowledge and just a real nice, sincere person.

I will keep playing....I was just hoping to get a better handle and not waste all this material.

Larry Bratton
12-13-2010, 9:23 AM
Thank you Ross for that enlightening post. Yes, many times ppi and dpi are used interchangeably in error.

Donna Bihm
12-13-2010, 2:42 PM
Not my thread but it sure sounds like I need to do some playing with Corel and photos. Will check out the processes/programs you guys have posted. Always love learning something new but usually just dont take the time, creature of habit I guess. You've been an inspiration:)!

Larry Bratton
12-13-2010, 6:52 PM
Donna,
Absolutely the best thing you can do. The more you experiment the more you learn and the better you get at doing them. It's a tricky endeavor but not really that complicated. Have fun!

Hannu Rinne
12-17-2010, 5:40 PM
Here is a plaque I made to our breeder. The picture is engraved on marble, using Photograv3 / 300 dpi ( picture is modified in Corel PhotoPaint ).

Hannu

Bill Cunningham
12-19-2010, 9:43 PM
Photograv works fine.... 99.999% of getting a good etch on Granite (The stone laserbits calls 'marble' is also granite) is making sure you have fine tuned the original image, to match the photograv .dat file that will be processing it. I have also spent a considerable amount of time fine tuning my photograv .dat files to give me exactly what I want with the way I pre-tune my input photos. They have to match. This is not something that you can learn from a book, it takes lots and lots of practice on lots and lots of scrap to get consistently good results that you can consistently trust not to ruin your 'good' granite ..
174507

Dee Gallo
12-19-2010, 10:17 PM
Beautiful piece, Bill. Proof that pre-press work is critical. Can you be more specific as to what you mean by "fine tune the original image to match the photograv .dat file"? Is there something more than size and resolution? I've only used it in the most basic sense.

While on the subject of 1-Touch, it seems to require .NET Framework... is this something okay to put on my computer just for testing the program or will it cause me trouble down the road? I don't really need 1-touch, but I'd like to see what it's like for myself (R&D addict).

cheers, dee

Bill Cunningham
12-19-2010, 11:12 PM
Beautiful piece, Bill. Proof that pre-press work is critical. Can you be more specific as to what you mean by "fine tune the original image to match the photograv .dat file"? Is there something more than size and resolution? I've only used it in the most basic sense.

My original fine tune photo to .dat file was done through repetitive testing, testing, and retesting. Start out with the generic black granite .dat file and play with the pg controls and see what happens on 'your' machine when etching.. What I do suggest, is keep the photo in colour, so you can use the 'photo adjustment lab' under 'adjust' in photopaint, (you rarely ever hear this function mentioned) but turn the saturation down to -100 so it looks like a BW image. Use the other sliders to set up a pleasing 'to your eye' image, click OK, then convert it to a 8 bit greyscale from the desaturated 24 bit colour image, then process that with PG and the .dat file you created by testing and re testing. The final output will be set for 'your' machine, and may not work on another one..

Dee Gallo
12-19-2010, 11:28 PM
Thanks for the breakdown, Bill. I've always prepped photos in PhotoShop, but I'm going to give your technique a try.

Wish me luck! dee

Tracey Bakewell
12-20-2010, 3:02 AM
I have been working on this all day long, thanks to this post, you guys all have just saved my life! Especially the youtube reference above! It is WAY easier than using Photograve! Love you all!!! Nitey Nite!

Dan Hintz
12-20-2010, 6:12 AM
Dee,

.NET is one of Microsoft's sets of DLLs/plug-ins to increase functionality of the OS. If you don't use it, it just takes up space on the hard drive, so no harm, no foul.

Larry Bratton
12-20-2010, 9:54 AM
Thanks for the breakdown, Bill. I've always prepped photos in PhotoShop, but I'm going to give your technique a try.

Wish me luck! dee
Dee, I too use Photoshop, but I found that photo processing for engraving using nothing but Corel Draw and Paint can streamline the process so to speak. Photoshop gurus sometimes thumb their noses at Photopaint, but I particularly like being able to apply the Floyd Steinburg and other dithering when converting to 1 bit B&W in Photopaint. Plus, if you have the photo imported into Draw, you can edit in Photopaint and it saves your changes right back into the Draw screen.
Bill speaks the truth on fine tuning, and practice is the best teacher. Remember, every photograph is different and requires it's own set of adjustments. I have not been using the adjustment lab as Bill has suggested though. I have been converting my photos to greyscale and working from there. I am going to try Bill's technique with the adjustment lab.
Merry Xmas!

Martin Boekers
12-20-2010, 10:56 AM
Photograv works fine.... 99.999% of getting a good etch on Granite (The stone laserbits calls 'marble' is also granite) is making sure you have fine tuned the original image, to match the photograv .dat file that will be processing it. I have also spent a considerable amount of time fine tuning my photograv .dat files to give me exactly what I want with the way I pre-tune my input photos. They have to match. This is not something that you can learn from a book, it takes lots and lots of practice on lots and lots of scrap to get consistently good results that you can consistently trust not to ruin your 'good' granite ..
174507

Bill, You are absolutly right when you say you have to work with the images.

I think too may of us want a one stop fix all. It just doesn't work that way.
Photos come in as many variations as there are photographs, so it is
not realistic to to think that you can hit one button and life will be good.

The problem is again the software manufactures make it sound that easy.
Some have luck with whatever versions they are using and others don't.

Quality of the photo means everything. The old computer term fits here
GIGO (Garbage In = Garbage Out)

It you take time to work with the images and halftones you have a better
chance of creating a nice image on marble or granite. There is a reason
why some work is so much better than others, that work doesn't
come from a one button process. Prep work is a key. If you get and image that
engraves well, use it as a bench mark. Study it check the size and resolution,
check the image mode (sRGB, RGB, CMYK etc) check the sharpness, check the dynamic
range, check the histogram there are many things to go through. Once you understand
why the image looks good engraved you can adjust future phortos along the same lines.


Then you have to calibrate your settings for the laser, there has been discussions here on that and a bit of searching will find it. Sometimes the settings can be as little as a couple of percentage points off andd it can make an engraved difference as night and day.

Photos are a challenge, One stop software may be good enough in many instances,
but do you want to be just good enough or want to produce really nice images?
It does take work.

As for PG software company not providing good tech support. I really hate to say it but software tech support is a problem with most software. I have had issues with Corel, PS
you name it support was almost non-existant. It's ashame I have resolved most of these issues through a forum, much better response and knowledge. It should be easier to
get good input from the publisher.

Maybe an enraving forum contest for photo engraving might be interesting. Hmmmm

Frank Corker
12-20-2010, 11:35 PM
Nice job on the heart shaped piece Bill.

Bill Cunningham
12-23-2010, 8:55 PM
Nice job on the heart shaped piece Bill.
Thanks Frank.. I appreciate it, knowing it comes from someone with your artistic skill..
I have just finished a group of black granite memorial plaques and two wooden ones to commemorate the 9 Canadian medics killed while serving near Kandahar, and have just been asked to do a memorial plaque for a young female soldier murdered by her perv. commanding officer.. (there's been quite a bit about this in the news, he just got sentenced to life, for this murder, and the one of a civilian)
I don't know who made the oak memorial case for these plaques, but they did a very nice job.. They might even be members on the creek someplace..

Dee Gallo
12-23-2010, 9:43 PM
Quite an impressive memorial display, Bill. The people reflected in the glass seem very moved. You've definitely got this granite thing down pat. Thanks for sharing this photo.

cheers, dee

Bill Cunningham
12-23-2010, 10:00 PM
Quite an impressive memorial display, Bill. The people reflected in the glass seem very moved. You've definitely got this granite thing down pat. Thanks for sharing this photo.

cheers, dee

This was one of the photos sent to me by my contact at the base, who arranged the display. The people in the picture were family members of the 9 soldiers being commemorated.. I had a invite to go, but the base at Trenton Ontario was too far to make it at that time..