PDA

View Full Version : How to enlarge images without losing resolution?



daniel coyle
11-18-2016, 10:18 PM
Lately I have been engraving enlarged versions of logos and images. I find the logo on the web and increase its size on my software (Chinese Laser Cad software) and, viola, I get a really poor image that does not engrave well or even has hash marks. Is there a way to take an image and scale it up without losing resolution?

Joe Pelonio
11-18-2016, 10:29 PM
Yew, you have to trace it to ceate an EPS file, convert back to a bitmap to engrave, if your software does that. Lots of time consuming work, especially if a lot of detail. The alternative is to find a higher resolution image to begin with. Bitmaps, especially jpegs lose resolution as you increase size, because they are just. A series of pixels (dots).

daniel coyle
11-18-2016, 11:23 PM
Thanks Joe. I use a website called Vector Magic that can convert Jpg, Png etc. into EPS files. It is extremely easy. Will that work or is this a fantasy shortcut? Once it is in EPS form you are saying I need to convert it AGAIN, back into a bitmap? I can't just engrave from the EPS image? Do I "enlarge" the EPS image before converting back to a bitmap and, if so, what is the best way to do this?

Kev Williams
11-18-2016, 11:41 PM
If you have Corel, use the Photo-Paint re-sampler. Forgive the big pics, but it helps explain-

original pic:

http://www.engraver1.com/erase1/stang1.jpg

Now, the next four pics I enlarged using the resampler. Starting with the above pic, I'm resampling at 125%,
and THEN I use the unsharp mask, percentage at 40%, radius at 2, zero threshold. Then repeat the resampling and
unsharp mask 3 times until the pic is effectively 200% of the original. The resampler doesn't just upscale everything, it
also splits the pixels somehow. There's still some pixelation as you get larger, but nowhere near as bad as just upsizing
the original some other way. The first large pic is the resampled, compare it to the 2nd and 3rd same-size pics... the
2nd was upsized once using my old PhotoSuite, the 3rd resized using 'photo resizer'. They're okay, and can probably
be sharpened up to look better, but check close, the resampled pixelation is much less... :)


http://www.engraver1.com/erase1/stang2.jpg

http://www.engraver1.com/erase1/stang3.jpg

http://www.engraver1.com/erase1/stang4.jpg
http://www.engraver1.com/erase1/stang5.jpg
http://www.engraver1.com/erase1/stang6.jpg

daniel coyle
11-19-2016, 12:03 AM
So, getting Corel is the key then, you are saying? The resampling tool allows for high resolution scaling?

Kev Williams
11-19-2016, 12:30 AM
I'm sure there's higher-quality solutions for upscaling photos, but probably on the spendy side... I'll just say that I upscale a LOT of photos and graphics, and this is the best way I've found, for the money anyway. I use Corel X4, and I paid $35 for an online download about 2 years ago, probably cheaper now...

Michael Hunter
11-19-2016, 5:51 AM
So, getting Corel is the key then, you are saying? The resampling tool allows for high resolution scaling?

Corel Photopaint is good, but almost all photo editing software will resample to a higher resolution. If you don't need the whole (expensive) Corel Graphics Suite, then something like Paintshop Pro will manipulate your photos at a much lower cost.

It is well worth you trying out the Vector Magic route - once you have converted the bitmap into EPS you will be able to make it ANY size without any further messing about.

George Bokros
11-19-2016, 6:55 AM
Nice Mustang

Bill George
11-19-2016, 8:32 AM
If your taking logos off the internet, you might need to check the copyright laws. They are low resolution in most cases to prevent bootleg copies. You can purchase logos in vector format or ask the owner of the logo for one to use.

Ross Moshinsky
11-19-2016, 8:42 AM
I very rarely will engrave a logo that is a "bitmap". In some occasions I have little choice but generally speaking, if it's a logo, it's vector art.

So my recommendation is to learn how to find vector logos on the net and also learn how to vectorize images.

daniel coyle
11-19-2016, 11:49 AM
Ok. Lots of helpful or potentially helpful counsel here.

When I vectorize, using Vector Magic (http://vectormagic.com/online/download?id=18788109&k=Y64BWfxLxWk36Z3iDMixxsRWf21kEuFj), into an EPS or SVG I find I am not able to import this image/file into the chinese Laser Cad software. I can import PNG or JPG just fine. Under "supported file types" when I import it doesn't list EPS or SVG but does list, beside PNG and JPG, a couple dozen other types including BMP, DXF, TIF, AI and 16 others (but not CD). Vector Magic says it can download "vectorized images" into SVG, PDF, EPS or a "vectorized" PNG (is that a thing?) I thought PNG was a bitmap? I will play with this more and see what happens

When looking for vector logos online, where can I go to find them? Nonetheless, if I do find them I am wondering how I import into my current platform, given the problem I mentioned above, and assuming the vectorized images are EPS or SVG.

I had a version of Corel Draw (I think 11 or 12) on another computer and was able to save/(vectorize?) images as AI (which my current platform says it can import.) If this is a good solution what do folks think is the best option as far as a cheap corel package goes?

Art Mann
11-19-2016, 12:26 PM
As you can see, Kev's samples are gradually getting worse and worse. The apparent degradation is most evident among smooth curves or lines. That is the type of graphics you desire to upscale. No program, no matter how sophisticated, is able to create visual information that wasn't already there. For line art, the only way to increase real resolution is to vectorize the original image. Once that is done, the lines and curves will always scale sharply and accurately, just like Joe said.

Robert Delhommer Sr
11-19-2016, 2:00 PM
How about using Inkscape (a free program) and convert to a vector, resize & convert back.

Ross Moshinsky
11-19-2016, 3:33 PM
Ok. Lots of helpful or potentially helpful counsel here.

When I vectorize, using Vector Magic (http://vectormagic.com/online/download?id=18788109&k=Y64BWfxLxWk36Z3iDMixxsRWf21kEuFj), into an EPS or SVG I find I am not able to import this image/file into the chinese Laser Cad software. I can import PNG or JPG just fine. Under "supported file types" when I import it doesn't list EPS or SVG but does list, beside PNG and JPG, a couple dozen other types including BMP, DXF, TIF, AI and 16 others (but not CD). Vector Magic says it can download "vectorized images" into SVG, PDF, EPS or a "vectorized" PNG (is that a thing?) I thought PNG was a bitmap? I will play with this more and see what happens

When looking for vector logos online, where can I go to find them? Nonetheless, if I do find them I am wondering how I import into my current platform, given the problem I mentioned above, and assuming the vectorized images are EPS or SVG.

I had a version of Corel Draw (I think 11 or 12) on another computer and was able to save/(vectorize?) images as AI (which my current platform says it can import.) If this is a good solution what do folks think is the best option as far as a cheap corel package goes?

At this point you need to do some research. This topic has been discussed many times and I know I've given very specific advise on how to deal with logos when being imported in a program like LaserCad or similar programs.

If you want to cut boxes, you don't need much knowledge. To do graphic design and manipulate artwork, you need to learn how to do it and what works. It's taken me years to learn how to manipulate artwork to achieve optimum results. It's not something you magically learn over night.

daniel coyle
11-19-2016, 8:32 PM
Ross, if you have already given out lots of advice on this subject and have a link to where you have done that, it would indeed help me in the research I am doing. Thanks in advance for that.

Robert, I used the inkscape idea and it seemed to work. It certainly improved things. I was able to increase the scale and get a more refined engraving. However, the improved engraving still has a hash mark effect to it. The old bitmap based image (that hadn't been vectorized) looks like widely spaced hash marks and the new one still looks like it is composed of hash marks though much more closely spaced. Any ideas? I took a picture with my phone that was really good but I couldn't download it onto the site here so I had to take a low quality pic with my computer camera.
347854

Bill George
11-19-2016, 9:37 PM
Taking a cr@ppy image into Corel or Inkscrape and Saving As a Vector is not going to work wonders. Using the Search function will.

daniel coyle
11-19-2016, 10:04 PM
Okay, thanks Bill, but now I'm confused. It seems like some people are saying if I vectorize a bitmap it is vectorized and then can be scaled up without losing resolution. You are saying that if the image is poor to begin with vectorizing it will just minimize how bad it gets when you scale it as opposed to scaling it as a bitmap, correct? Also, when you say use the search function, I assume you mean to search for a higher quality image? If so, I have done some of that and haven't found anything. Seems like some logos are never put into a high quality version and/or those versions are not posted on the internet. I'm doing this work pro bono for a nonprofit that helps disabled and elderly folks and I'm not sure they are really on top of their branding and Logo work

Kev Williams
11-20-2016, 12:29 AM
A couple points to clarifiy.

You cannot vectorize photographs of everyday things like cars, people, trees, etc. Well, you can, but what you'll get is 'cartoonized' graphics. Not good for laser reproduction.
But while you can't vectorize everyday photos, you CAN turn them into bitmaps. This simply means the computer has broken the photo into tiny bits-aka pixels- each having its own color. How big the pixels are is determined by the DPI/dots-per-inch being used. How many colors available for each pixel depends on more 'bits' - an 8 bit bitmap allows for 256 colors, 16 bit allows for 65,000 colors, close to 17,000,000 for 24 and 32 bit bitmaps.

HOWEVER- for engraving photos with a laser, you only want a 1-bit bitmap, which is simple black and white and nothing else...

I should point out here that many Western lasers will completely convert color photos into engravable photos automatically. Most Chinese lasers will not, which makes all this necessary.

So this is where grayscale and halftone/dithering come in. Now you have to convert your color photo or bitmap into simple 2-color bitmap. Only it's not all that simple. First you change your color original to grayscale. That's the easy part. Then comes contrast adjustments, then converting to halftone, which simulates grayscale by mixing black and white dots (or squares or whatever) to render the various dark and light areas. Choosing which halftone or dithering method is the hard part. Lots of learning curve.

So that's 'working with photos'. And when enlarging/upscaling photos or bitmaps, all those bits get bigger, and all the detail gets proportionally worse. The simple rule is, start with the biggest original possible...

A vector graphic by (my) definition means it has a "toolpath", a defined line that has a starting point and an ending point, and in the case of anything but a straight line, intermediate points. (Corel calls points "nodes") And all of these points will have an X and Y axis coordinate. These points and their coordinates are how all CNC plotters know where to go and what to do. The lines, boxes, or whatever shapes they end up as are 'contours'. An "open" contour has different start and end points. "Closed" contours have the same start and end point. Closed contours can be "filled" or "painted" or whatever you like to call it. Open contours can't be painted, they're only purpose is as a toolpath. Closed contours are also toolpaths, but their use as a toolpath is optional. Running any contour as a toolpath is what we all know as 'vector cutting'

What is typically vectorized are images of graphics or shapes or letters that have sharp, defined edges, that can be traced by a trace or vector program. Or you can trace (digitize) your own graphics. But it's much easier if the computer does it. :)

Once you've created and saved your vecotored graphic, it, unlike a bitmap, can be resized to ANY size thereafter with NO loss of detail.

Bill George
11-20-2016, 10:07 AM
Okay, thanks Bill, but now I'm confused. It seems like some people are saying if I vectorize a bitmap it is vectorized and then can be scaled up without losing resolution. You are saying that if the image is poor to begin with vectorizing it will just minimize how bad it gets when you scale it as opposed to scaling it as a bitmap, correct? Also, when you say use the search function, I assume you mean to search for a higher quality image? If so, I have done some of that and haven't found anything. Seems like some logos are never put into a high quality version and/or those versions are not posted on the internet. I'm doing this work pro bono for a nonprofit that helps disabled and elderly folks and I'm not sure they are really on top of their branding and Logo work

You have most of it. You will not find "free" top quality vector art online. I have a lot of vector art I have paid for and don't give away. If your indeed working for a non-profit you need to contact the companies that sell the art you require and apply for a grant. Dover sells a lot of vector images in packages. Link> http://store.doverpublications.com/

Searching.... you can find so much information on this forum just by searching and reading. When I was teaching full time the community college where I was at offered evening classes on learning in Photoshop or Illustrator basics you might look in to that. Like Ross and others have pointed out, you don't learn these graphics skills in a week, sometimes it takes months or years.

Kev Williams
11-20-2016, 1:24 PM
Thread: How to enlarge images without losing resolution? (http://www.sawmillcreek.org/showthread.php?249058-How-to-enlarge-images-without-losing-resolution/page2)

I just did a test conversion, turned out pretty well. It only took a few minutes, here's the steps I took. Note that the pics are actual size screen shots

First, I found some fairly detailed and small clipart to try, these trees. Note the original image is only 380 x 285 pixels...
347879

I copied the image and pasted into Corel Photo-paint.
Rather than go thru the small-steps upscaling, I just did a one shot 250% upscale. (Note that Corel says small up-steps works better, but honestly, one big step works just fine for most jobs)
This is the bare result
347880

Then I went to the Unsharp mask tool. I just played with the Percentage and radius numbers until it looked good to me.
I believe the settings were around 250% and 4 radius... anyway it sharpened everything up nicely.
347881

I saved it, and uploaded it to the Vector Magic site and let it do it's thing.
Turned out very well, only HOW well I won't know because I won't start an account just to download it.
So, part of the before/after screenshot is what we have here.
For reference, it took about 3 minutes for the changeover, half the time for the original vector, the other half when I opted for 2 colors...
347882

I also let my 22 year old Casmate vectorize it. Took exactly 8.25 seconds.
I exported it as a DXF to Corel, and this is the result. I did no editing. (I have found nothing better than Casmate for vectorizing) ;)
347883

I combined it in 2 sections, and painted as shown, half blue with red outlines, the other half brown with green outlines.
The as-finished size direct from Casmate is 9.2" x 6.5".
347884

Not bad for what started out as a very small image. Other than combining and coloring, I did no editing at all, I didn't even remove the partial text that was vectorized. It's completely editable and re-sizeable.

And anyone can do it. FWIW I'm actually pretty impressed with how Vector Magic did with it. :)

daniel coyle
11-20-2016, 8:30 PM
Thanks Kev, for the quick explanation on bitmaps and for the example test run. For what its worth, regarding the bitmap explanation, I am not using a photograph to work from but a logo
347926
I don't currently have corel draw but downloaded inkscape and will see if there is a similar function there. If Corel Draw is the way to go does it make sense to purchase the X4 version that was recommended earlier?

Bill, I went to the link you sent and I didn't find any images or vectors but just books? Did I miss something there? Also, I do understand that there is a wealth of information available from searching all of the posts and I usually do spend a little bit of time doing this before posting any questions directly. If there is a post or two that you know of that would be particularly good for me to review I would certainly love the lead. In the meantime I will work with the good advice and ideas I have already gotten here from everyone.

Kev Williams
11-20-2016, 8:50 PM
Thanks Kev, for the quick explanation on bitmaps and for the example test run. For what its worth, regarding the bitmap explanation, I am not using a photograph to work from but a logo
347926
.
It's a logo, yes, but it's not in vector format. What it is, is an image of a logo, which is, as far as computers are concerned, a photograph :)

But, as I noted above, it's "traceable" because the colors have defined, reasonably sharp edges. However, at 244 pixels wide, it's extremely small. I've enlarged it 250%, and worked the colors out of it, and while it will trace just fine. The thumbnail here looks great, but when you see the enlargement, you'll notice how bumpy the sides of the letters are. This is the problem with upscaling an image that's simply too small in the first place. These bumps will transfer to the traced vector art, and will have to be edited out, which is a whole 'nuther can o' worms. It's do-able, but time consuming...
347947

Gary Hair
11-20-2016, 9:28 PM
I have to throw in a couple of things here.
First, a digital photo is a bitmap - period. It can be saved as a tiff, bmp, gif, jpg, etc., etc., but it's still a bitmap. What sets a bitmap apart from a vector file is that it is defined by dots that are a particular color, or combination of colors, and a particular quantity of dots in the horizontal and vertical axis (resolution). A vector file is defined by objects that have specific geometry - x/y coordinates of start points and end points, angles, diameters, circumference, etc., all of these mean they can be scaled very easily by simply calculating the new values associated with the objects. This doesn't work on a bitmap because all you can do is create more dots from the information given - basically guesswork. There are, however, programs that do a pretty good job of this, one of them is Photo-Magic, which is integrated into Corel PhotoPaint. If you use it to do the enlargement first, you'll get a much better result than by resizing in Corel Draw, and your subsequent trace using Corel will be better as well. Still not perfect, but better than just resizing. This is part of X8, not sure when they added it but that would be reason enough to get X8 if it's not in previous versions. I'd advise against X4, get the current version and you'll not be missing out on features and support, as well as an upgrade path if you choose.

If I have an image that needs to be vectorized then I'll start with auto-trace and see if it will take much editing, if so I'll send it to William Desrochers at Excalibur - he is fast and does an amazing job for a reasonable price. I'm sure I could learn to vectorize as well as him but by that time I'd be old(er) and gray(er) and I'd rather pay him a bit and have it done while I'm working on something else that is making me money.

Wilbur Harris
11-20-2016, 9:36 PM
You can get that converted to a vector with vectorfactory.biz (http://vectorfactory.biz)...prolly 5 bucks and a days wait. Be sure to tell them black and white - one layer. Also, see the above post for another individual that does the same.

Scott Anders
11-20-2016, 10:33 PM
This logo would be insanely easy to just redraw with either Inkscape or Corel (i wish they were all that easy), 10 minutes tops probably more like 5. The typeface is Crillee if that helps, give it a go :)

Scott Anders
11-20-2016, 10:45 PM
Here's a screen cap, took about 8 minutes but the 3 swoops and the kerning could do with a bit of refining.347950

Here you go, tidied up the swoops and kerning347951

Bill George
11-21-2016, 8:50 AM
Bill, I went to the link you sent and I didn't find any images or vectors but just books? Did I miss something there

Dover art has more than books, do some Browsing.

I need vector art for my vinyl machine, both Amazon and eBay have vendors selling legal packages.

PS On the Dial a Bus logo, if he is doing a promotional is is not easier just ask them for a digital copy?

Ruben Salcedo
11-21-2016, 1:39 PM
Perhaps this won't help the OP much, but I think still is withing the topic.

Take a look at what Google is working on.

https://research.googleblog.com/2016/11/enhance-raisr-sharp-images-with-machine.html

daniel coyle
11-21-2016, 7:00 PM
Thanks all for the responses. I have a much better sense of how this whole thing works, why and what the options are (and that there are more than a couple). Scott, thanks for throwing that last drawing together. I will be trying out all of the different suggestions going forward and will send the results of this one as soon as the piece that will be engraved on is complete. Thanks again!