Difference between Vector and Raster images
The war of raster images vs. vector images has already been won; however, many people still question which is better? We are going to guide you through the difference between Vector and Raster images. A better question might be, what’s the difference? To answer this question, let’s take a moment and lay out the particulars of each one and then, hopefully you’ll be able to answer the question of which is better or yourself.
What are Raster Images?
A raster image, also known as a bitmap, is a full-color image comprised of hundreds, thousands, and maybe even millions of colored pixels.
Each pixel on its own represents nothing more than a tiny square of color. The concept of raster images is very similar to pointillist paintings. Each point in the painting, just like each pixel in a digital image, is important for the whole picture to turn out right, but taken out of context means very little.
The quality of these images is often determined entirely by how many pixels are present in the design. Raster images are measured in pixels. For instance, an image may be five thousand pixels high by thirty-five hundred pixels wide.
The exact unit of measure for raster images is known as ppi (points per square inch) or dpi (dots per square inch). The number of pixels in a single area will determine the number of variable colors possible and, therefore, will determine the level of nuance that can be applied to gradient colors, which offer smoother contrast.
Digital cameras create extremely complex raster images comprised of nearly countless pixels to produce the high-resolution images that we see on our cell phones.
As you can see 2 colour vector images are less detailed for laser engraving, although the quality will stay the same when scaled, opposed to raster, which will blur and become pixelated
Now that you’ve read about what raster images are and how they’re used, you’re probably asking yourself what the downside is. I’m sure you love your digital photos, and the cameras that major phone companies are creating just keep getting better and better. Have you ever tried to resize a photo yourself?
The major problem with raster images is that they lose integrity when stretched. This dilemma is most apparent when design graphics. Have you ever been working on a PowerPoint presentation for school or work, and no matter what you did, the images you placed just kept coming out all blurry and blocky?
This is because as each pixel stretches, its square corners become more pronounced, creating that blocky effect that you see.
What are Vector Images?
Unlike raster images, which are comprised entirely of pixels, vector images are designed using mathematical formulas that define certain geometric primitives. In other words, vector images also called “line-art,” are made of simple geometric shapes.
Each color in a vector is assigned to a single simple polygon or circle. These colors then have defined edges that are restricted to the shape they’re in rather than their size.
This simple fact is what makes vector images far more malleable than raster images, as they are almost infinitely resizable.
Because vector images have no minimum resolution requirements, it allows these files to be far smaller and take up far less space on any device. The image resolution of vectors conforms to the output of whatever device is used to view it.
Common uses for vector images would be things like logos, illustrations, technical drawings, specialty signs and printing, and engraving and etching. They are also used in CAD, Engineering, and 3D graphics.
Vector images are recommended for use with Laser Engraving machines because they are scalable and can be manipulated without losing quality.
If you are engraving a large project with text, for instance, you will want to be able to scale your laser cutting font up and down to the correct size without losing any quality
The only time you might want to use a raster image program over a vector program might be when you’re looking to make a photo-realistic design with gradual shifts in colors and shading.
When creating any design that is meant to look more like drawn images with defined edges, vector images are the way to go.
Not only can you change the size of the image with degradation, you can also change its angle without losing the integrity of the original image.
Now that we have covered a detailed summary of the difference between Vector and Raster images, here is a quick guide for reference next time you are determining which format to use for your cnc project.
• Raster programs best for editing photos and creating continuous tone images with soft color blends
• Do not scale up optimally – Image must be created/scanned at the desired usage size or larger
• Large dimensions & detailed images equal large file size
• It is more difficult to print raster images using a limited amount of spot colors
• Some processes cannot use raster formats
• Depending on the complexity of the image, conversion to vector may be time-consuming
• Raster images are the most common image format, including jpg, gif, png, tif, bmp, psd, eps and pdfs originating from raster programs
• Common raster programs: photo editing / paint programs such as Photoshop & Paint Shop, GIMP (free)
• Shapes based on mathematical calculations
• Vector programs best for creating logos, drawings, and illustrations, technical drawings. For images that will be applied to physical products.
• Can be scaled to any size without losing quality
• Resolution-independent: Can be printed at any size/resolution
• A large dimension vector graphic maintains a small file size
• Number of colors can be easily increased or reduced to adjust printing budget
• Vector art can be used for many processes and easily rasterized to be used for all processes
• Can be easily converted to raster
• It is not the best format for continuous-tone images with blends of color or to edit photographs
• Common vector graphic file format: ai, cdr, svg, and eps & pdfs originating from vector programs
• Common vector programs: drawing programs such as Illustrator, CorelDraw, Inkscape (free)