I have heard of vectors and have apps that use vectors but I'm wondering if I'm missing some nuances of what a vector is. It seems like lines and shapes. Can someone give me a quick "Vectors for Dummies"?
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Okay. I'll have a go hoping I can make it sound easy, hoping that someone else will fill in with anything I have left out.
The difference between jpegs and vectors (which often have a .svg ending) is that jpegs are made up of lots of colour pixels which make up the image and vector images are made up of mathematical points and lines or curves filled in with blocks of colour. It means that vectors are much smoother and you can make the image as big or small as you like with no degradation in the quality of the image because the mathematical points and lines are recalculated. Pixelated images will degrade because the software has to guess what colour pixels to remove or fill in if you are decreasing or increasing the size.
If you look at a very old blog post of mine, you can see how I converted a low resolution jagged BW pixel file into a vector file which I was then able to use to create a stencil which can be cut with a cutting machine. Sign companies or printing companies will prefer vector files especially for logos because they can print any size sign or letterhead and the image remains consistent.
http://annpassmore.blogspot.co.uk/2011/07/creating-stencil.html
This blog shows how I converted a colour image to a black and white jpeg but lots of apps do that now as you probably know.
http://annpassmore.blogspot.co.uk/2011/07/converting-photographs-to-black-and.html
If you want to convert a photo to a black and white vector image there are a couple of apps that do this, the best one I know is probably Adobe Capture with the Shape option. You can also see what the image will look like directly from the camera option. It will still save the original pixel file as well as the vector file. I also used an app called VectorSnap but it doesn't seem to exist anymore. Imaengine creates vector files too but with colour. Adobe Draw enables you to create colour vector files and you can import Imaengine files into it and change it.
As for actually changing a black and white vector file using the points and curves, I think you use to be able to do this with the Inkpad app. This used to be free but has been taken over by a developer and now costs and I haven't bothered to buy it. It may have a name change - can't remember.
Photographs are always taken as pixel images. As soon as you convert a photo to a vector, it really becomes a graphic image. One of the problems on the iPad is that you can't save a vector file into the Photos app so what you need to do is either email it to yourself, save it to Dropbox, save it in a file manager app like Documents or drop it into another app which handles vectors otherwise it will just save it back as a pixelated file.
The question is what do you want to do with vector files anyway? If I do doodles and sketches sometimes I want to smooth them out and a vector app does this and then you convert it back to jpeg:
View attachment 94466
Otherwise, the only other reason for saving vector files is to transfer them to a PC and use them for cutting out shapes using a cutting machine or if you have designed a logo, for printing. Also, to resize a graphic image for printing.
Technically, all pixel based images are called raster images, (as opposed to vector). So jpegs, gifs, pngs, tiffs and even raw files are all raster.
An interesting development is the vexel art form which is a raster format (pixel) trying to emulate the clean lines and often simplified palette of vector graphics.
E.g, from Wikipedia,
Yes.Going out on a limb here, but I remember "rasterizing" layers in Photoshop. (Text, I believe) was I turning a vector into a raster file?