Laser Engraving True 8bit Shades of Grey

[Lee DeRaud]

8X8 1/2" squares does not equal 256, only 64, so how would you be able to count them anyway? I was kinda confused what you were talking about when you requested that. It just did not add up to 256 and was not even sure how to do what you were asking. However, I have lasered 16X16 squares on Birch Ply that does equal the 8bit color pallet (256 shades). I scanned it in grey scale so it will be easier to tell the shade differences. Lee, can you count all 256 shades?

Sorry, I started typing 8"x8" grid and lost the train of thought somewhere in the middle. That said, with the squares out of order, there's no way to tell how many distinct shades of gray there are in that picture, which is the whole point of this discussion. For instance, are the last squares in the first and second rows different shades? Bloody hard to tell, especially since there are multiple shades of gray within each square.

[Rodne Gold]

Jeff , there are 100's of photographic type C02 laser engraved images on the forum , it's not unique artwork or IMHO, artwork at all unless you took the picture.....
The process you use is , as I have said before ,is not really that useful for most of us here as it relies on material reacting to a burn, whereas most of our lasers work by using a very high energy density to vaporise. The "burn" on wood we get is incidental to the process , its really just resin staining and char , most laser guys don't actually want that side effect when working with most materials ..we try to minimise heat affected zones.

[Jeff Woodcock]

Sorry, I started typing 8"x8" grid and lost the train of thought somewhere in the middle. That said, with the squares out of order, there's no way to tell how many distinct shades of gray there are in that picture, which is the whole point of this discussion. For instance, are the last squares in the first and second rows different shades? Bloody hard to tell, especially since there are multiple shades of gray within each square.

I know it's hard to tell when lasering on Birch Ply because of the grains in the wood does effect the shading, but that is the same effect I get when lasering an 8bit image on the same substrate. My image to gcode program interprets colors based on the 8bit color pallet into the 256 shades and converts that to code for the 256 different power levels. I can bring in a 8bit greyscale image, but it will give me the same results. Can anyone really count 256 shade differences with the naked eye anyway? With that being said, I don't think I can convince or satisfy anyone here on my results of any kind of testing I do.

[Scott Shepherd]

image1.jpgimage6.jpg

Here's two images from Universal's website. I imagine both are using their HPDFO system. I think you'd be hard pressed to say the image on leather isn't stunning. They have another photo that's on stainless steel that is really amazing quality, but it's naked baby bottoms and I didn't want to post it on this forum. You can go to http://www.ulsinc.com/markets/graphic-imaging and click on the babies and you'll see it.

I don't think anyone doubts that you have some good images. What I take a little issue with is stating that if no one else posts a photo to this thread, then by default, it makes your images the best on the entire site. There's are literally 1000's of photos on this site over time. Just because you haven't seen them all doesn't mean they don't exist. Just because no one's reposted them in this thread doesn't mean they don't exist and it's not possible.

The work I've seen in person from the HPDFO system on stone has been the best images I've ever seen, period, including your work.

Have you seen the HPDFO system in use? It's work? If not, you really should look into it.

[Jeff Woodcock]

Scott, that is very, very good laser engravings and I thank you for posting them. I hope one day I will be able to get those kind of results with my new 5W 445nm laser diode engraver build. Looks like I need to adjust my beam down smaller to get that kind of detail also. Time will tell.

This is all I asked that someone post a comparison because I could not see what everyone else was seeing. In no means was it a competition, just a comparison request. It's not easy to search for images, only with words and I searched for several.

Thank you for your compliments of my work too. Jeff

[Paul Phillips]

Jeff, first let me say that you do some very nice work, but I think where you've lost most of us is that your bringing a home made hobby laser to a forum where most of us have tens of thousands of dollars invested in equipment that can do what your doing in minutes with better results and wondering why we're not amazed at what you're doing. On it's own it is pretty amazing what you've been able to do with not much money invested, you have a definite talent for pioneering a cheap way to engineer and engrave your own at home, that's pretty impressive, but I think you would be more well received on another forum as others have already stated, maybe the CNC or woodworking forum. To me it's kind of like bringing your Honda Civic to the Ferrari club, ya it's cool for a Honda but we have freakin' Ferraris! If you do a search for photos on here you will find some awesome ones, here's one thread that comes to mind.
http://www.sawmillcreek.org/showthre...ted+photograph

[Jeff Woodcock]

Thanks for the recognition of my accomplishments Paul. I really do appreciate it. That link you posted to the engravings/paintings is some very amazing and impressive art work, but that process has nothing to do with what we were discussing concerning lasering shades of grey.

[Lee DeRaud]

Your machine must be turnkey and cost a small fortune, or no one here will be amazed.

You don't need to spend a lot of money to amaze us, you just need to do something amazing.
Dialing down the attitude about 12dB would help too.

[Ross Moshinsky]

This is a situation of "that's cool but..."

The results look good and it's interesting that you were able to achieve them with such a low cost device BUT similar results can be achieved at a much faster speed with a regular, but more expensive, CO2 laser.

I see a lot of posts on here that I feel fall into that "That's cool but...." category. First, I don't pay much attention to photos of engraving anyway. Catch the right angle and view something from far enough away and it can look spectacular even if it's not. Second, a lot of people on here are hobbyists and what they are displaying simply doesn't apply to us. It's hard to monetize a lot of the things I see posted on here. I typically won't post in those situations but on a rare occasion I will. In this case, I think some people on here are being a bit over critical and harsh in their tone but that's life on an internet forum.

[Hilton Lister]

You do that. It's always interesting to see new ideas and other people's way of doing things. I found your work quite impressive. I have all the tools and software to laser photos
but am seldom happy with the results from a commercial point of view because I find it very difficult to process the photos within in the time you can reasonably charge for.

[paul mott]

Hi Guys,

From reading the comments in this thread it appears that some are perhaps seeing what they want to see rather than seeing or fully appreciating what is actually here.

Like many others I have, for many years now, been re-producing photographic images using the halftone and dot-dithering techniques but the technique Jeff is showing us here is subtlety different.

Initially I did not think this technique would be possible using a C02 laser, mainly because the required variations in output power levels would be less than 2% and all at the bottom end of the power scale. After some practice, advice and encouragement from the diode laser team I discovered that not only is it possible with a CO2 laser but that the results could be quite outstanding. Jeff may argue that I am ‘cheating’ by pulsing my laser at 12.5kHz but that is the just way my CO2 laser varies it’s output power levels.

In any event this is not a totally new technique – most commercial laser machine’s software has handled grey-scale image reproduction for many years now, but in all the instances I have seen they either 'dither', 'half-tone' or reduce the image bit depth to below the 8bit.

I don’t think anybody is claiming that the technique Jeff is presenting here is better than any other technique but for those that wish to embrace it – it could be another string to your bow.

Paul.

[Jeff Woodcock]

Thank you Mr. Mott.

That was an excellent explanation! To let you know, I don't think your cheating, I just don't fully understand how your controlling your lasers power.

[Scott Shepherd]

John, I'm sorry, but what I'm now learning is, your new laser build and engravings will not qualify for the engraving section of the forum either. Your machine must be turnkey and cost a small fortune, or no one here will be amazed.

Jeff, it's comments like this that are putting you at odds with some people. I don't see your point. You seem to portray the cost to do this at nothing more than a red dot pointer, yet you ignore the cost of your CNC machine that it's stuck to. If you add up the cost of your machine, then you can buy a laser, a brand name laser, brand new. How that makes your machine any different than any of ours is something I don't understand. As mentioned numerous times, your photos are very nice. However, they aren't anything that's not already possible, quality wise, with what's available today, off the shelf. That's where the confusion comes in for many of us. I applaud your creativity and what you're developing, I just don't understand it, other than it appears to be a labor of love. People on here, for the most part, have bought lasers to make money. 3 hours run time on a 9" x 7" piece is something most of us can't understand. Perhaps that's the disconnect. No one's saying you haven't achieved something cool. We just can't understand how you make money with it. For you, you seem to have no intentions of making money, so that's fine. But most of us are running businesses and we just don't get it.

For the same money, we can do the same, or so close 99.9% of the public can't tell the difference, we can engrave far more materials, we can do it faster, we can do it more profitable. That doesn't mean we are haters or don't support what you're doing, it just means it's not fair to pretend your machine has no more cost than a $6 laser pointer, when that's just not the case.

What else can you engrave on? Wood? Leather? Paper? Canvas? What are it's limitations?

If I'm not mistaken, you're laser it hooked to this :
Screen Shot 2013-05-31 at 8.12.56 AM.jpg

[Jeff Woodcock]

Scott, my name is Jeff.

If you watched my video it shows my mini laser engraver and that is what I am doing this work on. My K2CNC router I purchased many years ago to do rotary engraving. My plans are to mount a more powerful laser on it in the future. How much would a 39" X 24" CO2 laser cost? I don't do this to make money, so the time it takes is irrelevant. I already have the servo router, so it's only practical to make it multitasking instead of buying another machine, especially for just hobby use. Well I say hobby, I will be able to cut gaskets with it for my machine shop business.

I can engrave on wood, mirrors, artist canvas and cut cardboard gaskets so far. I have not tried leather yet, but I suspect the smell would be overwhelming.

I don't believe my posts have been read or followed thoroughly, because I am finding myself doing allot of repeating of information.

[Mike Null]

Jeff

As I indicated early on I was pleased to have you join our forum because you added a new technology (at least to some of us) and you built it yourself.

Like a good many others I do engraving for a living and there are many things that I don't have the time nor inclination to try. But I find this forum valuable because we all share ideas and know how. The hobbyists are especially valuable to me as I regard them as our "test pilots" for new and interesting things we can do with our equipment.

I perceive engraving photographs on wood to be a waste of good wood but I can appreciate some of the results and techniques others have posted.

Would I try to emulate what you've done--no even if I had the time and skill--but I do find it interesting.

Anyway, we've had to remove some posts from this thread for being too contentious and I hope that we can all appreciate the other's point of view without belittling or attacking it.