We often do not think about our software in terms of why it does something in a certain way or even how it is capable of assisting us in creating our art. However, the process behind the scenes that allows us to create our digital art, truly is an art-form in itself. In this issue of Digital Hacks, I will be showing you behind the curtain of Adobe Photoshop and introduce you to the basic theory of how it all works. I look forward to introducing you to the basics and continuing to teach you about Photoshop using Digital Hacks as our "online classroom" until you have mastered the software for yourself. Oh, and don't worry I have tons of creative tutorials, tips, and tricks coming up in future articles to make your life as a digital artist easier.
Adobe Photoshop (Ps) is an image editing application, with an abundance of tools and commands for creating and working on bitmaps (digital images). Photoshop provides its users with tools for color correcting, retouching, painting, composting, and much more. Also, Photoshop comes with well over 100 creative and functional filters that can be applied to an entire image, selected areas, or specific layers determined by you
, the user.
Bitmaps also known as digital images consist of a rectangular grid, or raster, of pixels much like a digital mosaic. Photoshop works its magic through rearranging and recoloring the color values of those individual pixels that collectively make up your image. If you were to zoom in close on an image within Photoshop you will see the pixels that make up your image, as shown below:
In the above example, I have used a stock photo of an apple taken at 240 ppi shown at its actual sized compared against the same apple, but I have scaled (zoomed in) to 400%. As you can see, when we zoom in on the apple our image becomes pixelated; showing us the tiny squares that make up our digital image.
Image editing applications like Photoshop differ vastly from their vector counterparts, such as Adobe Illustrator or Inkscape. In vector applications, users work with objects that can be scaled, transformed, moved, stacked, and removed, either as individual objects or as grouped objects. Vector objects are defined by mathematical formulas, which makes vectors resolution independent
. This means you can scale a vector as large or small as you want and they will never become pixelated ensuring that they will always print smoothly and crisp (more information on vectors will be in a follow-up article). Unlike vectors, bitmaps are resolution dependent
, which means they are created at a fixed number of pixels per inch. Remember how when we zoomed in on our apple it became pixelated? Well, when we take a bitmap and try to enlarge it beyond its set resolution that pixelated effect is what becomes of our image. Tip:
Avoid pixelization and the need to go larger later by creating/scanning your image slightly larger than what you intended to make it in the first place. Remember it is easier to reduce size/pixels than it is to create them!
Pixels and Resolution
As digital artists, we use the terms pixels and resolution, but how many of us actually know what they mean or why they are important? If you are a self-taught artist like myself, you know that while tutorials reference these terms they often leave out information regarding them because they assume we already know it. Well, I do not like teaching on the basis of an assumption... so in this section I am going to explain both pixels and resolution in a way that is easy to understand for all of us.
Pixel short for "picture element" is the smallest part in a bitmap (digital) image. As we discovered earlier, when we zoom in on an image in Photoshop all of the individual pixels that make up the image will become visible. Anytime we work in Photoshop we are effectively copying, moving, and editing pixels.
Resolution is very important when working with bitmap (digital) images because they are resolution dependent. Resolution is measured in pixels per inch or ppi
for short. Many people do not realize this, but pixels can vary in size. For instance, if you create an image with a resolution of 100 ppi, each pixel would be 1/100th of an inch square. If you create an image with 300 ppi, each pixel would be 1/300th of an inch square; providing a higher quality less pixelated result. Tip:
When working on an image you know will eventually be printed, you need to work on a higher-resolution image. Need help calculating which ppi to use? Check out these: Printing PPI Calculators
PPI vs DPI: There is a difference?
Contrary to what many people think pixels per inch (ppi) and dots per inch (dpi) are not
the same thing. If you're reading this and thinking how can this be true or are simply confused... don't worry I will explain everything. You see, the problem started with people using the terms interchangeably because they assumed they referred to the same thing. Even worse, dpi became the more commonly used term by digital artists when it isn't even the one we are supposed to be concerned with.
Now as you previously read a pixel is short for picture element and your resolution is measured in pixels per inch (ppi). It makes sense that we would refer to our resolution as ppi, right? So what happened to cause the confusion and led us to using dpi? Well, pixels are often made up of "sub-pixels" - red, green, and blue light elements aka RGB
- that our eyes cannot see because additive
color processing blends them into a single hue. We only see the pixel level so this really has no impact on us. However, some manufacturers refer to the sub-pixels of a pixel as "dots" because they are similar to the CYMK dots of a printer. This CYMK dots act in a similar way except they utilize a subtractive
Dots Per Inch (DPI)
Printers do not function in a way that allows them to reproduce an image by placing pixels on top of one another. Instead, printers reproduce an image by spitting out (printing) tiny dots that consist of mixing four colors: Cyan, Yellow, Magenta and Key (Black) or CYMK. These colors combine to produce a wide variety of hues using the subtractive color model I mentioned earlier. Due to the nature of printing these "dots" there is space in between the dots, which is what dpi measures. It is important to mention that a higher dpi does not necessarily equate to higher quality because there is no standard dot size or shape in printing. In conclusion, dpi is just a technical aspect for a printer and aside from being good to know is not something used by digital artists.
Thank you for reading! Hope you have found this to be informative as well as helpful.
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