Photos engraved onto glass-Trotec 30W Speedy 300

[bryan henderson]

Good day creekrs

I am experimenting with glass the last few days onto mugs etc. I can easily engrave designs that I make with Corel Draw that are true black and white((lettering) but stuggling to find the correct setting to take a picture be it colour or black and white, transform this picture into black and white within Corel Draw(invert it if necesssary) but when it comes to engraving I am not sure the setting within " JOB CONTROL" software. If anyone can guide me thru some steps, that would be awesome. I looked at the videos that were on www.engrave.ca (http://www.engrave.ca) and they were great but not sure what I should turn on or off on my software for the laser, should half toning be on or off etc. I have a 30w Speedy 300 laser with a 2" lense focus and JOB Control software. I know there are lots of variable with the type of glass but some guidance would be awesome.

Bryan Henderson

[Craig Matheny]

First I would ask can you get it to work on flat glass photos on glass are difficult in the first place let alone now on a curve.

[Larry Bratton]

Bryan,
Check out this video by our member Roy Brewer. http://www.youtube.com/watch?v=yllZTBA0HO0

[bryan henderson]

I have attached a pic(original post) of what I am trying to engrave onto flat glass. So the steps involved to get this ready to laser engrave would be what????(this is where I need the help) I am thinking what I need to do is first of all import into Corel Draw, then resize to 4" x 6" and also change the DPI to 500. Then after this I need to pick a format like "stucci". If anyone can direct thru steps including what have to turned on and off in "Job Control", this would be awesome. Maybe a picture like this cannot be engraved. I am thinking I need to turn "halftoning" but not really sure. All Trotec'ers any steps or tricks would be perfect.

Bryan

[Bill Cunningham]

The picture shown is just under 4 x 6 @ 300 dpi. And yes, it has to be inverted to etch correctly. Glass has no contrast, and gets it's contrast from whatever dark colour you put behind it. If not converted to a negative before etching, it will look like a negative after you etch it. If the image is 300 dpi, do not etch it at 500 or it will not etch correctly. etch at 300, 600, or 1200..Never mix dpi's

[Martin Boekers]

I just started buying beveled glass and acrylic stands from Prism they engraved nice and are cheap.

You may want to try the black mirror JDS sells, I sell quite a bit of it.

Bill is the pro when it comes to glass, he has done amazing things with it!

[Bill Cunningham]

Bryan if your going to use photopaint to convert your greyscale image to a 2bit image.. Here is a simple manual method that rodney posted a few years back.. It works, and its a lot cheaper than photograv..


1) Convert to 8 bit greyscale. I start with colour, then desaturate to adjust and then convert to 8bit grey

2) Resize the image to the size its going to be engraved using 300 ppi (150 for less detail)

3) Bump up contrast and brightness about +25 in
both cases - you dont want the pic to be insipid areas of medium grey

4) Here's the VITAL part - use unsharp mask at 500% and a radius of 3-5 pixels - threshold 0 - this will exaggerate edges radically , but that's what you need. In fact you can do this and then STILL add another unsharp mask at 150 % , 1pixel and 0 threshold AFTER the 1st unsharp if you want even more edge detection

5) Convert to a bitmap using 150-300ppi and a diffusion pattern.

5) laser.

[Paul Williams from Nunavut]

Bill, I think I've got every step in your 6 step explanation of Rodney's formula except for the first 5)th step. I'm using Photo-Paint X5, and it seems to want to convert from 8 bit greyscale only to one of the following: Black and White (1 bit), Paletted 8 bit, RGB colour (24bit), CMYK (32bit), or Duotone (8bit), Lab Colour (24bit), Multichannel, Grey scale (16bit) and RGB (48bit). Should I be going to B&W 1bit or Duotone 8bit?

Also, at what point to I invert (to make the negative)?

In my case I'm setting dpi at 200 (as my machine is set at 400). Many thanks

[Paul Williams from Nunavut]

Bill, I think I've got every step in your 6 step explanation of Rodney's formula except for the first 5)th step.

Hmm, maybe I don't. Just tried a couple of flat glass tests and I get a fuzzy blob of frosted glass, with no definition. If I squint, maybe I can make out a face, but the rest is just a smudge of crap. Going to try again from scratch. But any advice would be greatly appreciated as frustration is beginning to reign supreme. :( Thanks all.

[Martin Boekers]

You can conver to a bitmap in Corel Draw without opening in PP.

select your bit map and on the toolbar go to Bitmaps and in the drop down select Mode and you have choices of the conversion.
Also it is very importatant to have the image to the size you want and don't resize it later. Also you should run it at the same DPI as the image.
There are many tps on youtube for this and it may be easier to learn from the videos.

[Martin Boekers]

See attached I am running X5 and this is where the conversion is. See the area I greyed out

[Paul Williams from Nunavut]

Thanks Martin. I'm going to upload three images: the original photo, the photopaint/coreldraw image, and the resultant reversed blob. Here are the steps I took, so I must be missing something:

CorelDRAW X5 - opened image, clicked on edit bitmap; Photopaint opens, removed background using cutout lab; desaturated image, converted to 8bit grayscale, resampled to size and 200dpi, increased brightness and contrast by 25%, unsharpened image by 500% with pixel radius of 5, then re-unsharpened by 150%, pixel at 1, converted it to blackandwhite 1bit, and engraved.

244410244411244412

[Paul Williams from Nunavut]

Ha! I think you're right. The image was set for 200dpi, but the machine was set for 400dpi. For some reason I was thinking that 200/400 etc. were the same thing as long as they were factors of each other. I'll try again and let you know. Thanks, Steve.

...

Took the machine down to 200dpi, same results altogether. :( Does it matter what the original photo's dpi was? Is that a factor that I need to consider?

[Martin Boekers]

It's hard to tell, but it looks like you have a grey scale image and not a 1 bit. If there is black, white & grey in your engraving file
it won't work. Glass is a low res substrate. The file to engrave should be a 1 bit image. Did you follow the instruction on the You Tube link?
That shows the basic process if you don't have a photo engraving converter software. Glass i s difficult to engrave to start with the image
you are starting with will provide a great challenge.

Have you tried changing the settings on your Epilog Driver? There are a few settings there that change the dithering.

[Paul Williams from Nunavut]

Hi Martin. I converted the file to black and white 1 bit and set the diffusion to jarvis, I think. If you mean the youtube video from engravingconcepts1 (which talks of dark and light backgrounds), I did try its instructions, as well as the ones Bill noted upstream. I have PhotoGrav 3 but my results using that are just as abysmal for me.

I notice when I get onto the driver I can change the dithering to the usual 6, I wasn't sure if I should dither a second time, having set the dither when I moved to the 1bit conversion. Just have to keep trying different settings. But thanks.

[Paul Williams from Nunavut]

Maybe its a lousy photo for this kind of thing, too much shadow on the one side and too bright on the other? Also, is the dpi meant to be based on the machine setting or the original photo setting. This photo loads at 72 dpi (or thereabouts).

[Bill Cunningham]

Bill, I think I've got every step in your 6 step explanation of Rodney's formula except for the first 5)th step. I'm using Photo-Paint X5, and it seems to want to convert from 8 bit greyscale only to one of the following: Black and White (1 bit), Paletted 8 bit, RGB colour (24bit), CMYK (32bit), or Duotone (8bit), Lab Colour (24bit), Multichannel, Grey scale (16bit) and RGB (48bit). Should I be going to B&W 1bit or Duotone 8bit?

Also, at what point to I invert (to make the negative)?

In my case I'm setting dpi at 200 (as my machine is set at 400). Many thanks

I use photopaint to do my tweaking, (contrast, brightness, etc.) the #5 step, you want a 1 bit black and white image. but tweak the image, size the image to the engraving size you want, 200 engraved at 400 should be ok, as long as the original image was not a low res. web image (72 dpi) if it was forget it you will never get a professional image. once tweaked/sized/sampled to the right dpi you can then invert it to a negative, remove the background, then convert to a true black and white with one of the dithering choices and laser.. The dithering process you choose should be the one that does the best job for 'you'

[gary l roberts]

Great instruction can't wait to give it all a try.