sigh, slate help please

[Finiousfingers]

I am trying to burn a pict onto slate. I have done a bunch of others and just need this one to complete the set of 5 for a friend. I have tried many things and keep coming back to not enough contrast in her pict to be of use. I have tried shading, burning, dodging... inverted, greyscale...
But I am missing something and its making me take a break tonight as its just going to ruin my sleep if I keep drinking as I try...

so. 5500 laser
Tried slowing down feed and power from 1800 - 800 speed and power from 130-80 and its all washed out. just a white blur. Maybe a little here and there but still crap ola on a cracker.
Attaching originals and then will up load my trials...some have various differences in same burn as I adjusted speed and power to play.

[Finiousfingers]

Here is a sample of unlearned mistakes.

[ThothLoki]

I am sure @nottingham82 will come and chime in here (riding in on his white horse as usual I am sure) 

One thing I suggest is that you bring your photo into gimp and add the cartoon effect. That is what I hear really helps with grayscale

Here is a video he made to help
https://youtu.be/UBKXeSfuVyk

[ggallant571]

I am no expert but not all images etch nicely in slate and shapes that occupy a large percentage of the total area seem to come out the worse for me. I tend to think of slate etching as mini explosions that will not create shads of grey.

People (dogs , cats, birds) with dark hair and dark cloths are somewhat better than those with light hair and light cloths. You may try shrinking the photo, enhancing the outline, removing all background or just switch to wood.

[nottingham82]

welll I reworked the photo.... I dont know if it will be better than your effort.  I'll engrave it and see.  Ideally you would want a higher resolution photo.... but you work with what you got.

Edit: it turned out pretty okish.  I only engraved it 25 mm x 25 mm It would probably look better at 80 or 85 but I didnt want to wait.  here is the technique I used.  https://www.youtube.com/watch?v=UBKXeSfuVyk

I ultimately messed with the curves till i liked it (that is a real technical term meaning I cant explain why I thought that was best) then I applied the cartoon filter then I inverted the image.  Then I used the paint bucket to fill in the black background white.

Also I forgot to add that I used my 2.5mw ttl laser settings 2000mm/min and 0-180 on the power. 

[Zax]

It looks better than OKish to me, you've earned the title "slate whisperer".

[ThothLoki]

Turned out great!

+1 on the Slate Whisperer name!

[nottingham82]

P.S. inverted pictures of people look like zombies

[kibodwin]

I too have been trying to engrave slate and what I found out is, don't try engrave pictures of people with sunglasses on, it just looks like they are a Mafiosi boss or similar. Also, the colours need to be inverted for better results, but this depends on the picture. I have a thick piece of slate I test on and sand down when I want to wipe the slate clean (pun intended!! =)
I usually try twice with the second time having the colours inverted. I can post my test engravings if you like but I think with slate it all comes down to trial and error.
Anyone got any ideas as to a finish to apply to the slate to make the contrast pop? I am thinking of applying varnish as they will be outdoors but not sure of the effect this will have..
=)

[Finiousfingers]

Thanks for the help!
I downloaded the pict and gave it a go with my 5500. I used 1800/180 for speed and power but it still was all white.
maybe I am not on pwm or ttl on the laser and thats my problem
I think I might need to shake the ghost out of my laser and redo the firmware again and a new cable and port.
Also when I tried to put a plastic L shaped DARK smoke plastic shield up it would shut off. like the static was interfering.
So I will have to look at how to destatic it and try again before I loose the color blue out of my left eye.


Once again, thanks for the Help I do appreciate a good forum group. Always quick to help and someone is always on.

[ggallant571]

For slate and mirrors I use:
    5.5W - 900/90
    2.5W - 900/255

The 5.5 does a much better job on slate while the 2.5 is better on mirrors.

Do you have the ability to measure the current consumed by the laser. If so you could use a terminal emulator and vary the power to the laser and record the usage using the M & S commands. I do not expect it to be linear but a S100 should be significantly more than S25.

[Finiousfingers]

Well I got a digital meter but have never used it on the board. Dont have clue as to what and where to test.
Been a long time since I did tiny tests.

Ill try dialing it back and see what happens. IN a better place with my tolerance this week so far... granted its monday 850am so time will tell when I get home.
But ill try 900/90 and see.

Once again, thanks for the good stuff.

[ThothLoki]

Well I got a digital meter but have never used it on the board. Dont have clue as to what and where to test.
Been a long time since I did tiny tests.

Ill try dialing it back and see what happens. IN a better place with my tolerance this week so far... granted its monday 850am so time will tell when I get home.
But ill try 900/90 and see.

Once again, thanks for the good stuff.

Just youtube how to measure current
https://www.youtube.com/watch?v=P660hTqkGiY

you will need to be inline with the + or - but have the meter set correctly. I may have blown a fuse in my meter.......once or twice........

[carolynsdad]

welll I reworked the photo.... I dont know if it will be better than your effort.  I'll engrave it and see.  Ideally you would want a higher resolution photo.... but you work with what you got.

Edit: it turned out pretty okish.  I only engraved it 25 mm x 25 mm It would probably look better at 80 or 85 but I didnt want to wait.  here is the technique I used.  https://www.youtube.com/watch?v=UBKXeSfuVyk

I ultimately messed with the curves till i liked it (that is a real technical term meaning I cant explain why I thought that was best) then I applied the cartoon filter then I inverted the image.  Then I used the paint bucket to fill in the black background white.

Also I forgot to add that I used my 2.5mw ttl laser settings 2000mm/min and 0-180 on the power.

Did you treat the slate surface with any product prior to engraving to get this result?

Mike

[nottingham82]

No that was just a broken piece I had laying around. It was the first thing I found so I just threw it under the laser.