PDA

View Full Version : Epilog 24TT and photo-engraving



David Sharp02
09-20-2017, 12:10 AM
The driver for the Epilog 24TT has a "Photograph" setting under Raster->"Basic Options". Does anyone know how this differs from Raster->"Basic Options"->"Clip Art"?

Do I need to convert images to 1-bit images? Or will driver take care of dithering for me? I've tried it out, but the results don't seem to be all that much different from Raster->"Clip Art".

If anyone has a 24TT and has any tips for photo-engraving, I'd much appreciate it.

Thanks,
Dave

Kev Williams
09-20-2017, 12:49 AM
I'm assuming that the Epy driver is similar to my Gravo driver, in that I have a "photo" mode, and I have a "grayscale" mode... Both do the same thing, but in grayscale mode there's a black/white ratio 'slider', where 50% is default, and I adjust- usually higher towards white- until I get it right. In photo mode, I just plunk in a photo and pick my power and speed and go. However, I've never tried a color photo, even though it will work. I've always changed photos to grayscale, then I work on getting the best contrast possible. The same photo will engrave in either grayscale or photo mode, but I always seem to get better results in photo mode.

and, it depends on the subject matter you're engraving, and what you're engraving it ON. I can get fantastic photos on stainless and certain plastics, but in 15 years I've never been able to engrave a piece of glass that looked good, I can never get the shading right...

Speaking of 'certain plastics', on the left is a photo I changed to grayscale, on the right is a photo of the laser engraved version
368193368194
The material is NON-laserable New Hermes black/white Gravoply II, 1/8" thick. The laserable material works, but the white is hard to get not too white, it's pretty fussy with the settings. I could never get it to look this good using the grayscale settings (I tried :) ), and what I wouldn't give to be able to do something like this in glass on a mirror...

Joe Pelonio
09-20-2017, 8:11 PM
Same here, after playing with it the first year (2006) I ended up doing all photos by converting to grayscale, then manipulating the contrast. The photograph setting only seemed to work on a very clear black and white photo that already had good contrast, which was rare. Most customers supply color with poor contrast.

David Sharp02
09-21-2017, 1:03 AM
You convert to grayscale, not 1-bit?

Most of the tutorials on YT seem to emphasize converting the image into 1-bit and resampling the DPI so that the dithering doesn't end up with resonance artifacts. If all I have to do with the Epilog is convert to grayscale and enhance the contrast, that's much easier.

Thanks,
Dave

Kev Williams
09-21-2017, 1:50 PM
When you convert to 1 bit, you get a specific dither or halftone the laser engraves from. The laser engraves black, doesn't engrave white, as is usual. The X factor however, is the width of the laser beam, which is wide enough to overlap and engrave a lot of white space between the black. Therefore, getting a 'correct' 1-bit dither can be a pain. However, most RF laser engraver's photo and grayscale engraving modes take all that into account, and they create their own 'internal' dithering and engrave accordingly. Some, my LS900 and ULS are nearly 'fully automatic', others like my Taiwan-made GCC, not so much. With the LS900, photo mode adjusting is resolution and speed/power, with less-being-more in the power settings. Grayscale is much the same but requires my choice of black-to-white balance, which can be handy but tricky. The GCC has a multitude of dithering options, but that in itself can be frustrating trying to find the right combination. But, at least, unlike glass lasers which usually must engrave only from 1 color bitmaps, I HAVE those options! :)

I'm not sure about this, but I think my LS900 and other similar machines will also adjust power on the fly during photo engraving, which doesn't happen when engraving 1 color bitmaps...