Photoshop CC tutorial 7: Colour modes and how to save for web.
PSD The PSD format (short for Photoshop document), is the ‘working’ file type in Photoshop. This is your main file and will contain all the working parts of your documents including things like layers, editable text, adjustment layers and effects. Use the format until you need to export it as something else like the next options. Most of the next file formats don’t retain all the editable layers and text so always keep a copy of your PSD handy. When working with InDesign or Illustrator you don’t need to save it as anything else, you can use your PSD in those programs just fine.
TIFF TIFF format is an excellent choice for print. They can be saved in CMYK, RGB, or greyscale colour modes. They can result in large file sizes.
JPEG JPEG supports CMYK, RGB and Greyscale colour modes. It is a ‘lossy’ compression format in that the higher the degree of compression, the more data is lost. The best way to end up with a high-quality image as well as a reasonably small file size is not to save it at a lower quality level, but to ‘optimise’ it using File > Save for web and devices.
GIF GIF (Graphics Interchange Format) images hold a maximum of 256 colours, making them ideal for images such as logos, maps or coloured headlines with drop shadows that are intended for display only on a website. GIF is not a suitable format for printing: while it will usually print, the results tend to be grainy and of poor-quality.
Portable Network Graphics (PNG) is a bitmapped image format that employs lossless data compression. PNG was created to improve upon and replace GIF as an image-file format. PNG supports greyscale and RGB. PNG was designed for transferring images on the Internet, not for print graphics, and so does not support color spaces (such as CMYK). PNG’s are great for websites that require images with transparency.
Note: when using PNG’s in photoshop it’s best to use 24 bit PNG not 8bit.
Found under Image > Mode > ...
Red, green and blue is how the computer displays colour on-screen. This mode should be used for any image that will be displayed on a screen e.g. Websites & Powerpoint documents. Use this colour mode also if you plan to print on your home ink jet as these types of printers are setup to accept RGB images.
This colour mode is used for commercial printing. Use this colour mode when creating images to be printed at a professional printers.
Resolution, dots per inch (dpi) and pixel per inch (ppi) are interchangeable terms in the design industry. Resolution is a term used to describe the quality of an image. The terms ‘high and low quality’ are used interchangeably with the terms ‘good and bad resolution’. The resolution of an image can be found under:
Image > Image Size.
Print resolution should be 300 ppi.
Web resolution should be 72 ppi.
Save for web
File > Open > Robot.jpg.
File > Save for web and devices.
You change the view to 4 up to compare different settings. By clicking on each of the four images you can adjust the settings to the right of the panel to increase or decrease the quality and file size.
You can zoom in and out to get a better view of the quality by using the + and - buttons at the bottom left of the panel.
When you have a setting you are happy with click on that image and choose Save.
Resizing images (preserve details)
The all new upsampling mode in the Image Size tool enables you to enlarge your photo using the new ‘Preserve Details’ mode that provides sharper results than bicubic. This mode also has a noise reduction that does a great job minimizing noise in your enlargement.