Unit 30- Digital Graphics THEORY P2 and D2

What Is P2?

What Is D2? For D2, learners need to use and show use of: different file formats different compression techniques different image resolutions different colour depths For each show the differences between the origional and final file sizes and discuss the differences

What Where? P2 Information Goes In Client Proposal (General Background Information) D2 Evidence Goes In Client Proposal A Mix Of Screenshots / Written Evidence

File Handling What Is File Management or File Handling It is making sure that converted files; file sizes; file formats eg jpg, bmp are in correct format in your folder structure Always name your files properly Always setup folder structures that help you find your work

Graphical File Conversion You cant just convert one type to another Many of these image formats are native to one specific graphic application and are not offered as an export option in other software. Not all vector and bitmap graphics convert / swap file formats If you need to convert between other formats, you can check into the image converters,image editors and image viewers 

Different compression techniques Compression can be lossy or lossless. Lossless compression means that as the file size is compressed, the picture quality remains the same - it does not get worse. Also, the file can be decompressed to its original quality. Lossy compression permanently removes data.

Let’s Watch A Video https://www.youtube.com/watch?v=2Qo5prktYNQ

File Compression PNG PNG is a lossless compression type. It is often used where the graphic might be changed by another person or where the image contains layers of graphics that need to be kept separate from each other. It is high quality. JPEG JPEG is often used for digital camera images because it has a fairly small file size for the quality that it displays. JPEG is a lossy format that offers a higher compression rate than PNG in the trade-off for quality. GIF GIF compresses images to a maximum 8-bit colour depth, making it unsuitable for high-quality photographs. GIF is often used where transparency is needed on the graphic. GIF can also be used to store simple animated images.

Compressing File Sizes Below are comparisons of the same image saved in several popular file types. Tiff, uncompressed 901K  Tiff, LZW lossless compression (yes, its actually bigger) 928K  JPG, High quality 319K  JPG, medium quality 188K  JPG, moderate web quality 105K  JPG, low quality / high compression 50K  JPG, absurdly high compression 18K  PNG, lossless compression 741K  GIF, lossless compression, but only 256 colors 131K

File Formats, Meanings & Compression

What Is Colour Depth?

Different image resolutions Image resolution is the detail an image holds. The term applies to raster digital images, film images, and other types of images. For example, an image that is 2048 pixels wide and 1536 pixels high (2048X1536) contains (multiply) 3,145,728 pixels (or 3.1 Megapixels). Higher resolution means more image detail or quality. Quality and Compression The quality of the image can also be manipulated.  Here we use the word "compression".  An uncompressed image is saved in a file format that doesn't compress the pixels in the image at all.  BMP or TIF files do not compress the image.  If you want to reduce the "file size" (number of megabytes required to save the image), you can choose to store your image as a JPG file and choose the amount of compression you want before saving the image.

What Is Best Where?