Graphics trick for glass engraving

[David Fairfield]

I was in the middle of doing a complex graphic for a glass engraving and the thought occurred to me, those guys on the Creek probably have a better way. :D

Here's the scenario: you need a black on white drawing of a military badge to engrave on a drinking glass. It must be a sharp engraving, not a half tone dot pattern. You don't have clip art but you do have good photos or scans of that badge. What do you do to make a drawing to engrave on a glass?

What I do is import the photo to a vector drawing program (adobe) then painstakingly make a black on white drawing of the badge. The results are excellent, but it takes a full day or two to render the drawing.

Over to you! :)
Thanks
Dave

[Darren Null]

I use the trace program in the free vector app Inkscape if it's complicated. there may still be an hour or two cleaning and tweaking (which I do in Corel), but it's still quicker.
http://www.inkscape.org/

[Mike Null]

I use the free artwork on the various military web sites. Often there is vector art for badges.

If I can't find any then I use Will at this site. He's very good, fast and very reasonable.

http://www.excaliburcreations.com/

[martin g. boekers]

I tend to work in Photoshop to get the image into "line-art" basically no middle tones. Depending upon the art I can res the art work up, put a bit of a blur on it, then toy with the brightness and contrast to smooth out the edges.

After I have the image to my liking (just black and white no middle tones)
I engrave at 1200 dpi 100 speed 85 power (Epilog 75 watt)

For me this gives it a sharp more consistent result.

Glass, everyone has their own little way to get consistant results, Someday with more and more lasers out there, a manufacturer may justify fomulating glass products designed for lasering.

For me at lower resolutions and power settings I would sometimes get an area that wouldn't have the sandblasted look (esp. on the black mirror from JDS). It would etch and you could see it at certain angle but if looked strait on some areas would appear to drop out.

This works real well for me on crystal bases that hold globes and those 3d laser crystals with pre-burned images in them.


Marty

[Scott Shepherd]

I agree with Mike- sub it out. No sense in spending hours or an entire day when someone will convert it for you for less than $20 in most cases.

If you enjoy doing it, that's one thing, but if you are getting paid to do it, then you'd be better off subbing it to one of the vector guys out there.

[Frank Corker]

I take it the trace feature has been considered at this point? After all it can make a hard job look bloody easy!

[David Fairfield]

Here's what I'm trying to do. Same client, different year, more complex design. I think trace feature is only Photoshop. I only know how to use Adobe Illustrator :(

Dave

[Darren Null]

Photoshop doesn't have a trace feature. A trace feature is a raster-->vector conversion. CorelDraw has one, Illustrator has (an arguably better) one, and the free Inkscape has (in my opinion) the best one of all.

[David Fairfield]

Thanks for that, I'll have to go read the manual now!! :D

Dave

[Frank Corker]

It was the Corel one that I was referring to, if you haven't used it before, then you are in for a treat!

[Larry Bratton]

Here's what I'm trying to do. Same client, different year, more complex design. I think trace feature is only Photoshop. I only know how to use Adobe Illustrator :(

Dave
David:
Photoshop doesn't have a trace feature. Photoshop is a bitmap based program. Tracing usually is used to convert bitmaps to vector. Corel includes one with X3. I don't use Illustrator, so I don't know. The best one I have ever used is included with my Enroute CNC toolpathing software. I use it to trace ,then export to DXF and then back into Corel.

[martin g. boekers]

Help me please!!! When you have a vector image with fills and you send it to the laser isn't it converted to a raster image before it is burned?

I maybe missunderstanding this process. I'm still relatively new to the laser, a little over two years, but I'm learning everyday!

Thanks for your help:)

Marty

[Mike Null]

Martin

The image remains a vector image. The laser driver rasters rather than cuts based on line width or color mapping.

[David Fairfield]

Marty

I make a black and white drawing so that the engraving has sharp crisp edges. I can also use a vector to enhance some edges (this was not done in the samples I showed above).

With a jpg, the laser interprets pixels and I get half tone dots and/or blurry edges.

The other advantage of making the drawing instead of using a cleaned up scan is that it looks like a professional graphic, not a cleaned up scan. I think that technology is catching up though so it may no longer be necessary to do the drawing from scratch.

Thanks everyone for the pointers. Although I'm still doing the drawings the old way in AI, I'm going to try whats been suggested here and also go look at the other thread on this subject, its been very interesting for me. :)

Dave

[Dee Gallo]

Dave, I'm an old dog still using the old tricks too. I find that I can redraw a design such as the one you show in about 30 minutes while I'm watching TV and have a much nicer job than tracing and fixing. Once you get the hang of it, it's very easy. I also do not use the drag technique, I just click on corners and convert the ones I want into curves. It's a much more reliable way to work and no surprises like you get with tracing or dragging. I've wasted more time using the "easy" way.

just my perspective, dee

[Doug Griffith]

You can trace in Photoshop by wanding, loading the layer/channel as a selection or any other way to create a selection and then go to the paths window and select "Make Work Path". From there you have the option to set your tolerance.

Though, in the end, tracing never works as good as drawing it yourself.

[Doug Bergstrom]

I have read many time here and on other sites about trace tools, and programs to make outlining or clipping easier.
The easiest way is to use the pen tool. Take time to learn and use it. It is the fastest and cleanest way to make an outline or clipping path for high quality output.
The trace programs, magic wand tool, selection tools are fine for web graphics but for print they just do not work. They put in to many points that can cause problems for Rip's, and generally take much longer to "clean up" then you can do with the pen tool.
Try it out and see the difference!

[David Fairfield]

Yeah the pen tool is extremely useful. I did the graphics for both the glasses I posted above by tracing a photo of an original medal mostly with the pen tool. But its not as simple as tracing because I need to interpret what needs to be white and what needs to be black to have a professional looking graphic. In a photo of a three dimensional object, there are a lot of grey areas in between, literally. Unfortunately, I've got no art or graphics training, so its not something I can do in half an hour in front of the tube! :rolleyes:

Dave

[martin g. boekers]

So the laser driver doesn't convert it to a bitmap in it's processing to burn?

If it does is it similar to say taking a copy of a photo and making a print from that. Going another generation and losing some of the detail in the process?
(basically taking a bitmap to start with and reprocessing it through the driver to burn)

Which brings up another question, Does Corel when you save a file that consists of bitmaps and vectors, lose anything, in the bitmaps or vectors in the save like you would with a Jpeg file?

This is getting deeper, but the more I understand of the processes what controls them the better work I can create.

Thanks in advance for your help,

Marty

[Darren Null]

So the laser driver doesn't convert it to a bitmap in it's processing to burn?
Effectively, for everything but hairlines, yes it does. Sort of. Instead of a row of dots for solid areas, you're burning a line, but no difference really.

If you save a corel file with a vector image, you shouldn't lose anything. CorelDraw can do some unpleasant things to bitmap files when you _import_ them; so you maybe get some loss there. CorelDraw isn't a 'lossy' format, but you have to remember that it's primarily a vector program. It can also do some strange stuff to bitmaps when feeding it to a printer driver.

[David Fairfield]

Marty,

The laser is basically an on-off system. Its either firing or its not, there is no middle ground. So when engraving any image, white is full off and black is full on. Any tones or colors between white and black the laser must interpret as dots.

For esthetic reasons, I do not want dots on my glass engraving, so I draw my graphics black on white, with no grey tones. This way I have solid engraved areas with crisp edges.

Dave

[Bill Cunningham]

Marty,

The laser is basically an on-off system. Its either firing or its not, there is no middle ground. So when engraving any image, white is full off and black is full on. Any tones or colors between white and black the laser must interpret as dots.

For esthetic reasons, I do not want dots on my glass engraving, so I draw my graphics black on white, with no grey tones. This way I have solid engraved areas with crisp edges.

Dave
That works well for fine lines, and low to medium density graphics, but some glass will actually have sections flake off the surface when trying to go for solid etching on large bold areas or hitting close to curvature limits of the piece.. The 80-or 90% black can substantially reduce this problem..

[martin g. boekers]

Thanks for the tip!

Some of the graphic I do on a regular basis have done that time to time.
I found that kicking the resolution up had helped to a point, I'll try with adjusting the density too!

Marty