Digital Basics Quiz Preparation

Basic Digital Image Concepts Aliasing & Anti‐aliasing Resolution Compression Raster & Vector Color mode & Image mode

Aliasing vs Anti ‐ aliasing These two letters are printed with the same font, size, and style. The only difference between them is that the left letter is aliased and the right letter is not. As you can see, the left letter has a jagged, “stair- step” effect that is the hallmark of aliasing. It is the way that computers display curves on the screen. The right letter has a smoother, fuzzier look to it. It is anti-aliased to simulate the look of a smooth curve on the screen. Images on a computer screen are composed of tiny block or pixels. Depending on the shape of the image, the pixels make it difficult to make a smooth image. Think a shapes out of LEGOS. A LEGO square would have a more accurate shape compared to a LEGO circle. Anti-aliasing help smooth the edges to create an even curve.

Can you pick out the image that uses anti- aliasing? How can you tell the difference?

Resolution Resolution is the measure of how many pixels are in a given space. Print Resolution is measured in DPI (dots per inch) Screen Resolution is measured in PPI (pixels per inch). PPI is used to calculate Megapixels. Digital Cameras are classified based upon Megapixels. The higher the DPI or PPI the more detail can be shown within an image. There is a large difference in image quality when you have 400 pixels verses 25 pixels.

The higher the Megapixels or PPI the larger the image can be before it becomes fuzzy, blocky, or pixelated. Why would having a high PPI be important when editing digital images?

Compression Compression is used to reduce file size for storage, processing, and transmission. Images can be compressed by converting them to different file types or by adjust the compressions setting within a specific format. During compression, data is removed from the image making the image less defined or sharp. The more or higher the image is compressed the more data is changed.

Raster vs Vector Raster Images Composed of individual pixels. Easy to edit Becomes blurry or pixelated when zooming Very detailed images File Types- JPEG, GIF, PNG, BMP, TIFF, PSD Vector Images Uses mathematical formula to create the image. Difficult to edit Images scales perfectly Limited detail File Types- EPS, SVG, PDF

What types of images should be created in a Raster format? Why? Why types of images should be created in a vector format? Why? Greater image detail, but poor quality when scaling Limited image detail, but infinite scalability.

Color mode and Image mode Both Image Mode and Color Mode are different functions, but they essentially deal with the same thing; the amount of color within an image. RGB mode- Best for digital image viewing. CMYK mode- Best for high quality color printing. Index mode- Best for color images who need to have a small file size like Web images. Grayscale- Printing images on a black and white printer or black and white images. Bitmap- The lack of grey makes bitmaps appropriate for text and other images that do not require subtitle changes in tone. Limiting the colors you use will decrease the file size. Modes 1.RGB mode (millions of colors) 2.CMYK mode (four-printed color/ This is a simplified version of the RGB mode. This is due to printers inability to recreate the millions of colors accurately.) 3.Index mode (256 colors) 4.Grayscale mode (256 grays) 5.Bitmap mode (2 colors Black and White)

1.RGB mode (millions of colors) 2.CMYK mode (four-printed colors) 3.Index mode (256 colors) 4.Grayscale mode (256 grays) 5.Bitmap mode (2 colors)

Resources aging/Conceptual/drawingwithquartz2d/Art/antialias.jpg aging/Conceptual/drawingwithquartz2d/Art/antialias.jpg html 07.html jpg/dpi.jpg?t= jpg/dpi.jpg?t= ap_VS_SVG.svg/2000px-Bitmap_VS_SVG.svg.png ap_VS_SVG.svg/2000px-Bitmap_VS_SVG.svg.png