Newbie question on lasering a photo

[Mike Galea]

I just purchased my first laser (a Chinese machine 80watt) which runs Lasercut5 along with Corelx5. I would like to start lasering photos onto different materials such as wood, anondized aluminum, leather. My question is what is the best way to save the file in Corel to get the best output. I changed the photo to B&W 1 bit, (which is what my instructions say is the best, but the output is distorted. Any help would be greatly appreciated.

[Dan Hintz]

Pics of the problem help here...

[Mike Galea]

Dan,

I am not quite sure what you are saying !

[Mike Chance in Iowa]

I just purchased my first laser (a Chinese machine 80watt) which runs Lasercut5 along with Corelx5. I would like to start lasering photos onto different materials such as wood, anondized aluminum, leather. My question is what is the best way to save the file in Corel to get the best output. I changed the photo to B&W 1 bit, (which is what my instructions say is the best, but the output is distorted. Any help would be greatly appreciated.

The best help you can receive is to read the old posts in this forum! This question has come up and has been answered many, many, many times in older threads.

[Dan Hintz]

You say the output is distorted, but that tells us nothing about the problem other than you're not happy with the output. Without a clear idea as to what the problem is, we can't really help you. Pics work wonders here...

[George M. Perzel]

Mike;
Not sure where you got your instructions but they are wrong. Save as greyscale bitmap and use Photograv or Gold method (search forum). BW 1 bit loses all shades of grey which is definitely not what you want.
Best Regards,
George
Laserarts

[Bill Cunningham]

Anodized aluminum and leather are both high res. materials, and as such you can etch them directlyt from a greyscale photo without using photograv. (experiment with speed power) Wood is not as high res, and the photo must be converted to 1 bit files first.

[Dan Hintz]

Bill,

You consider leather to be hi-res?! Aluminum, yes, but leather?

[Mike Null]

Dan

That depends on the leather. Some is indeed pretty high res. as are some types of wood. Obviously, textured leather wouldn't be one of them.

Often the detail on such substrates is determined by one's skill at operating the machine.

[Vicki Rivrud]

Hi Dan,
As with most Chinese lasers which do not process greyscale images, file preparation is paramount to the final result, a bit more time will be required.

As a beginner you really need to read the post here on the subject, looking into photograv for processing your file but you will have to prep the file a bit more in Corel before using Photograv. All photos are not created equal, so choice your photos well before attempting. I have found that a good balance of black and white will give you the best results. Using the "Gold Method" if a Photoshop user is great too, I use Corel.

There are several tutorials also posted on youtube and doing an internet search should also yield several more.
IMHO- you have to understand the process before you get the result you are looking for.

Vicki

[Dan Hintz]

Hi Dan,
As with most Chinese lasers...
I assume you meant to address this to Mike, Vicki... ;)

[Steven Cox]

Have of you guys heard of a plugin for Photoshop called Rastus if so then you'll know how brilliant it is for creating black & white halftone images that you'd swear are greyscale and are just brilliant for lasering photos. I tried photograv but I just couldn't get the results I wanted, then I found Rastus and it's a fraction of the price of photograv. OK so its not macro based so you'll need to do a bit of image adjustments before running it through Rastus but the results are well worth it. What's more I've been able to convert the worst low res photo's supplied by customers to produce a reasonable result.

Obviously good images are better but it's hard to educate some customers who can't get past...."but it looks gook on my computer" you know the type.

Here's a link for Rastus Info
http://www.telegraphics.com.au/sw/info/rastus.html

If you want some short cuts on creating images for laser with Photoshop/Rastus just let me know & I'll post a tutorial with some recommended settings.

[Dan Hintz]

Here's a link for Rastus Info


Sorry, sales are suspended pending new payment processing arrangements. Also: AVOID Paymate!
That doesn't look good...

[Steven Cox]

That doesn't look good...

Hi Dan, I took the link from an old bookmark, just looked myself can see that but the paypal link on the first page works. Although I'd question the price I paid $49 for it about 2 years ago which really was the best money I've ever spent on graphics s/ware. And if you are wondering... no I'm not affiliated with them.

I used Ratus about 20 years ago for outputting AO size posters, back in the days when an image setter would take days to process the plates. The rastus conversion however turned days into hours. But for the Laser you only need to work in greyscale but it is possible to do CMYK separations as well. When I couldn't get the results from photograv I thought back to the days of using Rastus, it took me a while to find it again but it was worth the effort.

I've now worked out settings for image conversion that works on just about any image (after its clipped) so it now takes me less than 5 min to convert an image ready to laser.

I tried to upload a sample image here but upload won't accept .tif saving an image .jpg won't work because the converted image is bitmap & .jpg doesn't save in 1 bit. So to give you a sample here's a corel file (x4) with the tif imported into it. Note unlike photoshop, corel doesn't display 1 bit images all that well. If you wanted you could engrave this yourself onto some light wood. Other than that if you PM me your email I'll send you the tif which its less than 1/2mb or send me an image of your own & I'll convert it.

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Lately I've also started exprimenting with using Corel Trace to vectorize the rastus converted images at this stage though the results are a bit hit & miss and definately not as good as running the tif image. File size as vector is also very large due to complexity of the nodes.

Regards Steve.

[Steven Cox]

OK I've worked out how to attach a zip in forum posts using the Basic Uploader link.

The attached zip contains a .tif image that's been converted by Rastus. Open this in Photoshop or PhotoPaint and view at actual pixels. Then zoom it to see the detail.
You'll see that its all black.... no grey scale!. The Halftone that Rastus produces is very detailed unlike anything that PS or PP can produce. I can tell you that this image engraved beautifuly on both natural and coffee bamboo ply.

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[Dan Hintz]

The Halftone that Rastus produces is very detailed unlike anything that PS or PP can produce.

You're kidding me, right? I have no problems whatsoever producing nice halftones from a myriad of programs, Photoshop amongst them (though I prefer Paint.NET for simplicity). There are multiple halftone algorithms, but in the end most will give you perfectly useable output. I'm not going to go look up their page again, but I'm willing to bet Rastus is simply using a standard (and well-known) halftone algorithm... if so, that algorithm is available on quite a few other programs.

The great thing is Paint.NET is free (along with the boatload of plug-ins that people are writing for it), and I don't need to pay $50 for another plug-in (Rastus) to get nice output.

[john banks]

Any suggestions on some command line image processing stuff I can play with (so they can be run silently and automatically when required)? Ghostscript seems to be the main one.

Irfanview (free) can run Ximagic Gray Dither plugin (free Photoshop plug in, but crashes in Irfanview when I try to write, but looks very capable, the preview boxes have some really nice dithers). Not worked out yet if I can run a photoshop plugin via Irfanview command line.

1Touch laser photo has also produced some nice results, as has Corel Photopaint.

Just need to decide what to settle on of this lot.

[Steven Cox]

You're kidding me, right? I have no problems whatsoever producing nice halftones from a myriad of programs, Photoshop amongst them (though I prefer Paint.NET for simplicity). There are multiple halftone algorithms, but in the end most will give you perfectly useable output. I'm not going to go look up their page again, but I'm willing to bet Rastus is simply using a standard (and well-known) halftone algorithm... if so, that algorithm is available on quite a few other programs.

The great thing is Paint.NET is free (along with the boatload of plug-ins that people are writing for it), and I don't need to pay $50 for another plug-in (Rastus) to get nice output.

Sorry, sounds like I offended you in some way. If so it was not my intension. For me and my chinese laser which won't print greyscale, Rastus is a cheaper way than Photograv and the standard halftones available in PS. Just a side note the Rastus plugin has been around for over 20 years, so if anything I think others might be using their algorithum.

[Dan Hintz]

Sorry, sounds like I offended you in some way. If so it was not my intension. For me and my chinese laser which won't print greyscale, Rastus is a cheaper way than Photograv and the standard halftones available in PS. Just a side note the Rastus plugin has been around for over 20 years, so if anything I think others might be using their algorithum.

I'm not offended, I just didn't think your conclusion was valid. If Rastus has been around for 20 years, as you say, to come to the conclusion that Photoshop (et. al.) can't compete in terms of output quality is short-sighted. While Rastus is certainly cheaper than PhotoGrav, there are plenty of free alternatives that are quite easy to use and have just as good (possibly better, depending upon your measurement metrics) output. Personally, I find PhotoGrav to be overblown and overpriced for what it does, but people like a one-click solution, even if it's not optimal.

One my own side note... I bet Rastus is using someone else's algorithm, not their own in-house design. Halftoning algorithms have been around for quite a bit longer than Rastus, so it's easy to take an existing algorithm and create a plug-in for a common program like PhotoShop.

[Bill Cunningham]

Yup smooth leather is very hi res.. you can get amazing photos by just sending a 300 dpi greyscale image directly to the laser.. Unlike granite and wood, no pre processing in photograv etc.. is needed.. The attached, is a 11 x 18 leather.. The photo does not do it justice..You can see every detail of the cowboys in the original..

[Martin Boekers]

Yup smooth leather is very hi res.. you can get amazing photos by just sending a 300 dpi greyscale image directly to the laser.. Unlike granite and wood, no pre processing in photograv etc.. is needed.. The attached, is a 11 x 18 leather.. The photo does not do it justice..You can see every detail of the cowboys in the original..

Nice work Bill! You are a master of photo work!

Yes halftones have been around for many years in the printing industry. It was a very specialized field
before even computers. It would be nice to have someone on board here that actually created halftones
for the printing industry and see if they can provide contructive "Tweeks" I have paid for PG many times
over. I still find it quick to work with and can produce "acceptable" results in less than a minute. I can
almost expect what I will get when I start with it. If I want to get a bit more control I tend to use the
method Roy Brewer (so kindly) posted on You Tube that uses PP.

Come on Dan show us some of your photo work!

[Bill Cunningham]

Nice work Bill! You are a master of photo work!

Yes halftones have been around for many years in the printing industry. It was a very specialized field
before even computers. It would be nice to have someone on board here that actually created halftones
for the printing industry and see if they can provide contructive "Tweeks" I have paid for PG many times
over. I still find it quick to work with and can produce "acceptable" results in less than a minute. I can
almost expect what I will get when I start with it. If I want to get a bit more control I tend to use the
method Roy Brewer (so kindly) posted on You Tube that uses PP.

Come on Dan show us some of your photo work!

While greyscales do work well with leather, I usually now funnel just about everything through P.G. It just makes life so much easier.. 20+ years ago, I used to make halftones with a screen and a Camera and the old 3 chem darkroom. Then came U.V. film and away went the darkroom, the next change was spray the UV exposed neg with a developer, and wipe it down with a kim wipe and rinse it off.. I used to use negs to make hard polymer dies for both hotstamping, and rubberstamps, Now, I don't think I have made a neg for anything in the last 7 or 8 years

[Steven Cox]

Yes halftones have been around for many years in the printing industry. It was a very specialized field
before even computers. It would be nice to have someone on board here that actually created halftones
for the printing industry.

Been there done that, many years ago but not before the era of computers and well before my memory started to fade a bit. It was around that time were processing plate separations through an imagesetter was a very time consuming process. Halftones made the job faster but there was a big trade off on quality unless you could to trick the imagesetter into continuous tone behavior.

Please let me make this very clear, I'm not trying to sell the rastus plugin. I have no connection with them although reading back on my wording I conceed it may have read that way . All I was trying to do was alert people to its existance and it wasn't my intension of getting into a discussion of who uses who's algorithms or what's the best method to output a halftone image. My appologies to all if it sounded that way, when it comes to image conversion I tend to be a bit passionate. If anyone would like to see how rastus outputs PM me a greyscale image and I'll run it through the plugin and email it back to you so you can try it on your laser. Additionally, I'd be happy to share my notes on the conversion process which could save some time experimenting.


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I'm sort of reluctant to add anything further to this topic but there is that's one thing that's being missed, although Dee did pick up on it and that is most chinese lasers won't do greyscale. As such a halftone does work, but, it works even better when you can trick the laser into a continuous tone behavior.

[Dan Hintz]

I'm sort of reluctant to add anything further to this topic...
Don't get scared away, Steven... add whatever you feel is appropriate to the discussion at hand. Without useful info from multiple people, this board would just be another Facebook without the pretty pictures.

[john banks]

Please expand more Steven, especially about the trick on the continuous tone behavior. The frequency of the half tone pattern is important? RDCAM v5 will do grayscale if you select "output direct", although the response time is not so fast and many materials don't show a difference in power as a clearly defined difference in color as much as a good dithered pattern.

[Steven Cox]

Please expand more Steven, especially about the trick on the continuous tone behavior. The frequency of the half tone pattern is important? RDCAM v5 will do grayscale if you select "output direct", although the response time is not so fast and many materials don't show a difference in power as a clearly defined difference in color as much as a good dithered pattern.

Hi John,

The frequency of the half tone pattern is controlled by the final DPI setting in the Rastus Plugin. The lower the DPI the corser patten will be, I've found 300 DPI works well with softwoods and 400 DPI works better with hardwoods. Note here that this is the output DPI setting not the input when exporting the image to Rastus I'm talking about. I've found it possible to start with a resonable looking low resolution image at 72 DPI, provided the physical size (print size in inches, mm or whatever) of the original could be achieved without enlarging the image and then output it to rastus at 300 DPI or greater and get some great results.

I have an older version of RD Cam (so I believe) that doesn't have a greyscale option. Perhaps if I've got some time later this week I could throw up some screen shots together with a how to for converting images with Rastus, but start it in a new thread and then reference it back here. Would that help?

[john banks]

Thanks. I would love to see a thread where a small source image is posted and contributors can post their dithers at an agreed output resolution and they can be compared. I can contribute a few processed versions too. I will start something unless you want to.

[Steven Cox]

Thanks. I would love to see a thread where a small source image is posted and contributors can post their dithers at an agreed output resolution and they can be compared. I can contribute a few processed versions too. I will start something unless you want to.

Go for it John, that's a great idea. I think the base image posted should be an unworked image so others can adjust the image as needed for their process and then perhaps give a brief on how the final image is achieved.

[john banks]

Can you suggest or post an image you think is suitable and I'll post a new thread?

[Steven Cox]

Can you suggest or post an image you think is suitable and I'll post a new thread?

Hi John,
The only forseeable problem is that SMC forums have a very restrictive upload limit on images. I thought about making the image downloadable from my own site but again the T & C's here are a bit particular about self promotion. So in order to give you and others a high resolution image to start with I've posted an image on 4shared.com. I figure using a file sharing site should avoid any conflict with the SMC T & C's. If I'm wrong about this or there's a better way to share images via SMC please tell me/us.

4shared.com. is a free file sharing site, my free account gives me 5Gb storage and I'd recommend anyone that wants to contribure either open an account there or another file sharing site. The high resolution image of ziggy can be downloaded from here. 4shared.com/photo/HzlKVFBP/ziggy.html just add the www.

The image you'll be downloading is my own image of my dog and give permission for any sawmill creek user to experiment and use this image of ziggy as you see fit.
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To only thing I've done to this image is clipped out the background and resized to 300 dpi no other colour or tonal adjustments have been made. The image has lots of white and fine details in the wiskers so I think this would be a good image to use for comparison of different methods.

[Chuck Stone]

..interesting to see how varied the results are. Just reaffirms that people
look for different things in an image.. they can all be different without any
one being more 'correct' than the others..