How to enlarge images without losing resolution?

[Bill George]

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]

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]

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]

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]

Thread: How to enlarge images without losing resolution?

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...
tree1.jpg

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
tree2.jpg

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.
tree3.jpg

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...
tree4.jpg

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)
tree5.jpg

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".
tree6.jpg

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]

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
dial a bus.png
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]

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
dial a bus.png
.

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...
dialabus.jpg

[Gary Hair]

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]

You can get that converted to a vector with 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]

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]

Here's a screen cap, took about 8 minutes but the 3 swoops and the kerning could do with a bit of refining.Capture.jpg

Here you go, tidied up the swoops and kerningCapture.jpg

[Bill George]

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]

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...h-machine.html

[daniel coyle]

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!