What is the main Difference between Adobe Photoshop and Adobe Illustrator?

Knowing the difference between Adobe Photoshop and Adobe Illustrator can help you choose which software to use when creating and enhancing your art. Adobe Photoshop generates raster (bitmap) images while Adobe Illustrator generates vector images. Note: Scanned art is converted to raster images.

Difference between Raster images and Vector images


Raster Images

Raster Images are composed of square dots called pixels. The more dots per inch (dpi) in an image the better the detail (resolution). If an image is scanned or created at a low resolution and later increased, the image tends to become blurry. Adobe Photoshop tries to fill in the missing pixels when the resolution is increased but it is not always successful. That is why it is recommended that you create and scan art at 300 dpi (preferred resolution for most manufacturers) or even greater.

The example at the left shows the blurry (jaggy) edges of a shape that was originally saved at 72 dpi and then enlarged to 300 dpi. The same thing happens when a small painting is enlarge too much in Adobe Photoshop. Enlarging the design increases the size of the pixels creating jaggy edges. Thus, you should not create or scan small paintings or any painting at low resolution because when increased too much the design will become blurry. Note: All of my art is created at 300 dpi with the smallest side of the design no smaller than 12 inches.


Vector Images

Vector images (objects) are made up of points that are connected (paths) by lines and curves. Because the object and placement on the page is described mathematically, the resolution is not degraded when the object is enlarged. Note: Vector file sizes tend to be smaller and print faster than raster files.


Comparison of Adobe Photoshop and Adobe Illustrator

The main tool in Adobe Photoshop (brush) is more intuitive to use than Adobe Illustrator's main tool (pen). The brush and pencil tools in Adobe Photoshop works similarly to actually painting with brushes and drawing with pencils but the pen tool in Adobe Illustrator uses a different technique that requires the user to click and drag the mouse to make objects. There is a definite learning curve in producing complex shapes in Adobe Illustrator. But once you master the pen tool you can make some fantastic free-form curves (called Bezier curves) that are absolutely smooth which would be difficult if not impossible to do with the brush tool in Adobe Photoshop.
Adobe Photoshop does have some vector tools such as the text, shape, and pen tools. Because those tools are vectors, the resolution is not degraded when the objects are enlarged.
The look and the shading of images in Adobe Illustrator is also different than in Adobe Photoshop. Adobe Illustrator uses gradients of color to shade an object so art created in it looks more illustrative. Adobe Photoshop shading is pixel by pixel so art generally looks more painterly.



When Should You Use Adobe Photoshop and Adobe Illustrator?

If you want to create 3D product mock-ups for your art, you need to use Adobe Illustrator. If your art style is painterly or you scan your art, you need to use Adobe Photoshop. If your art style is more contemporary or illustrative looking with crisp edges you may want to use Adobe Illustrator. Many artists that design patterns for the fabric industry find Adobe Illustrator better to use than Adobe Photoshop. Editing colors of objects for different colorways is easier to do in Adobe Illustrator than in Adobe Photoshop. And, if you want smooth and crisp outlines of motifs for the rubber stamp industry, templates for product development/design, etc. you will want to use Adobe Illustrator.

Using the pen tool in Adobe Photoshop is more difficult than Adobe Illustrator's pen tool. So I normally use the pen or brush tool in Adobe Illustrator when I want to make smooth-edged complex-shapes such as ribbons (shown in the example at the left). By working back-and-forth between Adobe Photoshop and Adobe Illustrator, you can create some interesting and beautiful art.