Converting programs for Engraving Manual Method and Adobe Photoshop

[Richard McMahon]

Great thread guys,
One thing I noticed with some old scanned photos is that they have a patterned effect from the texture of the photographic paper, like a honeycomb ,so just to add to the process I use a slight Gaussian blur of about 2-5 pixels until the pattern has mostly disappeared. Do this before the Filter - Sharpen process.
They tend to come out really good but now I just have to set up my laser to engrave them properly.
Also you can play around with the Graphic Pen filter (Filter - Sketch - Graphic Pen) to blend a lot of the small edges to straight lines. Play with the sliders on the right hand side to get the effect you want. It just adds another dimension to the photo when engraved.
:-)

[Darren Null]

It says in the Photograv manual that the converted file is a binary file and these types of files don't like to be manipulated or you lose the subject clarity

Ah, thanks. In theory rotating an image SHOULDN'T make any difference at all...you're just lining up (say) an 800x600 grid of square dots and turning them into a 600x800 grid, but with all the dots in the same place. I suppose different programs do tricky stuff on the way round.

JPG files, you have to save the rotated file, so you're adding another layer of lossy JPG compression, but for a 1-bit BMP it shouldn't make a difference.

[Bob Davis]

Rodne/Frank,

Love your work...Excellent.

[David Dustin]

Normal maps? I seek enlightenment, O guru. <--not sarcasm- I'm not good at 3D

Normal maps are used in 3d applications to fake depth.
Here are 2 images. The top one is a section of tread, the bottom is a normal map. A normal map is applied in addition to the image and it gives a great illusion of depth. A "bump map" can be used as well, where the image is grey scale, but normals are the best.

Consider yourself enlightened o-lasah-hoppa....

[Darren Null]

Thank you.
I shall choose to believe that "lasah-hoppa" is a seeker of knowledge.

[Neal Schlee]

[quote=Brian Robison;916156]
However, as a side note, I shorten the steps myself by not leaving Corel Draw. I've tested Rodney's method both ways and can't see the advantage to going into PhotoPaint. I know the steps by heart and have for probably a year or more. Takes only a minute or two.
I change a lot of Vector art into a bitmap before lasering.
These are the modified steps.
(1) Choose the image and convert to grayscale 300dpi.
(2) Under Bitmap, resample to the proper size.
(3) Under Effects / Adjust/ Brightness, Contrast, Intensity bump up Brightness 25, Contrast 25, Intensity 0 (these setting will stay after you do them the first time)
(4) Under Bitmaps / Sharpen / Unsharp Mask / percentage 500. Radius 2.
quote]

Another step I use is:
(5) Under Bitmaps / Mode / Black & White use a dithered pattern and preview to adjust intensity as needed.

I also sometimes adjust (3) Brightness and Contrast settings to suit photo.

Using these steps I get nearly identical results as Photgrav 2.1, as Brian stated, without leaving CorelDraw.

Thanks to all involved!

Neal
Lasertech Alaska

[David Dustin]

I have been working on trying to get photographs to lase for a few days now and have not gotten anything good at all (seems like I am on a roll).

My images even when using the "gold method" and variations of the "gold method" yield quite indistiguishable lased parts. As far as being able to maek some of the high quality lased photographs seen around on different sites, it feels like they are out of reach.

it is almost like taking a high level class but having missed the first semester.

My images look good on wood, OK on aluminum but on acrylic it looks like (insert bad word here). I am using 1/4" plexiglass.

Thanks,
David

[Bill Cunningham]

I used practically the same settings for plexiglass (acrylic) that I use on glass photographs size as needed, re-sample the 8 bit photo to 150 dpi, and convert to binary using what ever. I etch in reverse at 300 dpi 40-60% speed 100% power.. remember, your image must be a negative image because glass and plexi get their contrast from what ever is behind
Below is a rough etch in extruded acrylic.. Normally you would remove the background by making it pure black before converting to binary. Once you invert it to a negative image, the back ground becomes white, and the laser ignores it.. If the photo engraves in wood ok, then it should also work in glass if the dpi is low enough (you don't etch photos in glass with 600 dpi..) ths one was done with the cherry setting in photograv (the old one)

[Doug Griffith]

Is it possible your plexi is extruded instead of cast? It makes a difference.

[David Dustin]

And the newbie asks...
How do I know the differerence?

David

[Doug Griffith]

From my understanding:
1) If it's not clear, it's most likely cast.
2) Cast is stronger than extruded.
3) Extruded may have very fine extrusion lines if looked at through lupe.
4) Lasering extruded stinks more than cast.
5) Extruded is cheaper.

[Lee DeRaud]

From my understanding:
1) If it's not clear, it's most likely cast.
2) Cast is stronger than extruded.
3) Extruded may have very fine extrusion lines if looked at through lupe.
4) Lasering extruded stinks more than cast.
5) Extruded is cheaper.

5A) If it came from the window department at a Borg, it's extruded.

[Scott Shepherd]

When you laser the clear cast, it will "frost up" and look like etched glass. When you laser extruded, it won't. If you bought it from a hardware store, it's more than likely extruded and the wrong product for doing that.

However, you can take a can of spray paint, paint the backside and laser through the paint, and you'll end up with a nice product. Just use a fast drying paint like Krylon, Krylon Fusion, or Krylon H20 (some Rustoleum paints take hours to dry).

Hehe....Lee beat me to the borg comment

[David Dustin]

Dang, It looks like I have extruded then...

I'll try painting the back of it then lasing through it.

I tried black marble with the gold method and it works great, just had to make sure my image was at the same DPI setting I was lasing at (yeah I know, Iknow... obvious) and had to reduce the power settings.

Thanks for all your help.

David

[Frank Corker]

You'll know straight away generally if you have extruded or cast. Cast leaves a beautiful white engraving, perfect for the laser engraver, extruded is virtually clear and appears to melt the surface. The picture that Bill posted, had it been done on cast it would have looked fantastic. Of course as already mentioned, the smell. Cast acrylic has an almost sweet smell to it (gets too much if that is all you are working with) and extruded..... that just stinks the place up, it's horrid. They use extruded over here in the UK to make registration plates on vehicles, it's much more robust and doesn't splinter the way that cast does.