I know it sounds dumb, but what exactly is a vector, or whats the diff between vector and rastor. I always seem to get the two badly confused
Whats the Difference between Vector and Rastor
I know it sounds dumb, but what exactly is a vector, or whats the diff between vector and rastor. I always...
&nsbp;
#1
xValentynex
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#2
Coy
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Elite Designer
Posted 01 May 2009 - 09:17 PM
In simplest terms Photoshop is raster based image editing program. It has very powerful tools which can analyze and allow you to modify these pixels. Raster or bit mapped graphics are defined by a grid of pixels to Photoshop. Each pixel has a specific color value assigned to it depending what color mode you are working in it is defined differently. A pixel is usually very small so you don’t notice the individual pixels, they all combine to make up you image.
Differences between raster and vector image formats
A computer screen generally displays 72 pixels per inch and most printers work with 600-2400 pixels per inch. The terms ppi, pixels/inch, dpi, dots/inch and spi, samples/inch all are different terms for describing how the grid is laid out which is it’s resolution. The only difference between the terms are the devices being used. Scanners and monitors generally use PPI or spi. Output devices use dpi or lpi. Lpi is lines per inch which we will talk about in the future.
Drawing programs like Freehand and Illustrator are vector based which is very different. They use math to describe the shapes that make up an image. The advantage of using math to describe a shape is it doesn’t have a set resolution. The shape will display/print at the highest resolution the output device supports. This is very different then raster images which have a fixed resolution. Also fonts and therefore text is usually vector based.
The way each format handles resolution is very important. In Photoshop to achieve the highest quality you need to work at the correct resolution from the beginning. Each time you resize or alter the resolution the quality suffers.
As you can see a raster based image at 72 dpi has fairly jagged edges. When increasing the size to 200% the resolution drops to 36 dpi and it is really jagged. On the other hand a vector based image looks much less jagged since the curves are defined mathematically and resizing the image has no effect on quality
Differences between raster and vector image formats
A computer screen generally displays 72 pixels per inch and most printers work with 600-2400 pixels per inch. The terms ppi, pixels/inch, dpi, dots/inch and spi, samples/inch all are different terms for describing how the grid is laid out which is it’s resolution. The only difference between the terms are the devices being used. Scanners and monitors generally use PPI or spi. Output devices use dpi or lpi. Lpi is lines per inch which we will talk about in the future.
Drawing programs like Freehand and Illustrator are vector based which is very different. They use math to describe the shapes that make up an image. The advantage of using math to describe a shape is it doesn’t have a set resolution. The shape will display/print at the highest resolution the output device supports. This is very different then raster images which have a fixed resolution. Also fonts and therefore text is usually vector based.
The way each format handles resolution is very important. In Photoshop to achieve the highest quality you need to work at the correct resolution from the beginning. Each time you resize or alter the resolution the quality suffers.
As you can see a raster based image at 72 dpi has fairly jagged edges. When increasing the size to 200% the resolution drops to 36 dpi and it is really jagged. On the other hand a vector based image looks much less jagged since the curves are defined mathematically and resizing the image has no effect on quality
#3
Coy
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#4
xValentynex
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Posted 01 May 2009 - 09:21 PM
I dont have enough money for illustrator hahah but I usually try to keep my resolution high because i keep in mind that these might be printed...so i usually do 300 dpi with rgb or cmyk
#5
designumber18
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Posted 21 May 2009 - 03:45 PM
Coy explained it very well!
I would just add the fact that for some usage, Vector is the ONLY way to go. Logos should almost always be designed in vector, because your client may want to print it in a 1-color newspaper/magazine ad, for instance. Or save money printing 2-color business cards instead of full color (4-color). With the popularity of online printers, this isn't as much of an issue nowadays... but still relevant.
Additionally, most apparel (hats, shirts, etc) makers prefer vector files to work with. Screen printing is done with separate plates for each color, so CMYK files turn out cost more to be screen printed than files that can be broken down into 1 or 2 colors. Also, embroidery (like on a baseball team's hat) is almost exclusively with vector files, because they company needs to use individual color threads for each section. They can't use CMYK or RGB raster files, which create colors by combining the foundation colors.
Most importantly, vector images can be enlarged to any size with no loss of quality, whereas raster images can only be enlarged to a limited degree (usually 20% or so is safe) before they begin losing quality (the "jaggy-ness" Coy referred to).
Sometimes your client says "Don't worry, I'll only need it for my website", in which case RGB and/or CMYK are just fine. But inevitably, they'll come back and say "I want to print some t-shirts, and the company wants a vector file" or "I need to print a 200ft x 200ft building wrap... they need a vector logo"... If you have created their logo as raster, you usually can't justify charging a client to re-create it in vector format... so you're losing money by taking the time to re-do it. Safest bet is to start with vector for logos in the beginning!
Hope that makes sense! :-)
I would just add the fact that for some usage, Vector is the ONLY way to go. Logos should almost always be designed in vector, because your client may want to print it in a 1-color newspaper/magazine ad, for instance. Or save money printing 2-color business cards instead of full color (4-color). With the popularity of online printers, this isn't as much of an issue nowadays... but still relevant.
Additionally, most apparel (hats, shirts, etc) makers prefer vector files to work with. Screen printing is done with separate plates for each color, so CMYK files turn out cost more to be screen printed than files that can be broken down into 1 or 2 colors. Also, embroidery (like on a baseball team's hat) is almost exclusively with vector files, because they company needs to use individual color threads for each section. They can't use CMYK or RGB raster files, which create colors by combining the foundation colors.
Most importantly, vector images can be enlarged to any size with no loss of quality, whereas raster images can only be enlarged to a limited degree (usually 20% or so is safe) before they begin losing quality (the "jaggy-ness" Coy referred to).
Sometimes your client says "Don't worry, I'll only need it for my website", in which case RGB and/or CMYK are just fine. But inevitably, they'll come back and say "I want to print some t-shirts, and the company wants a vector file" or "I need to print a 200ft x 200ft building wrap... they need a vector logo"... If you have created their logo as raster, you usually can't justify charging a client to re-create it in vector format... so you're losing money by taking the time to re-do it. Safest bet is to start with vector for logos in the beginning!
Hope that makes sense! :-)
Edited by designumber18, 21 May 2009 - 03:50 PM.
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Graphic Design for print and web. 10 years of Proven success!
My site: http://www.designumber18.com | some additional work
My site: http://www.designumber18.com | some additional work
#6
jmillgraphics
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Posted 08 November 2009 - 03:07 AM
I dont have enough money for illustrator hahah but I usually try to keep my resolution high because i keep in mind that these might be printed...so i usually do 300 dpi with rgb or cmyk
No money for illustrator? Inkscape is pretty sweet.
Inkscape. Draw Freely.
Enjoy all your free vector drawing! Seriously, do the vectors! It's the only way to design.
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#7
joyasmith
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Apprentice Designer
Posted 04 February 2010 - 06:01 AM
Well..the basic difference between rastors and vectors is that vector is used for the cut style and the rastor is used for the print style for the fabric image. You have to be trace the image or the print as a vectors. Typically vectors images are used as a screening printing. And you can use photoshop for smart printing layer also....!!
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Edited by joyasmith, 08 February 2010 - 09:48 AM.
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