Making selections in a vector drawing is really easy. This is because they consist of discrete objects each of which can be selected and manipulated independently of the rest of the drawing. By contrast, bitmapped image is one continuous whole consisting of a matrix of pixels. Making selections in a bitmapped image is therefore much more complex and difficult than simply clicking on an object as you would do in a vector drawing. In fact, selections are such a big deal in Photoshop that there is a whole menu dedicated to selection options and techniques: the Select menu.

Having made a selection, you have the option of saving it so that you can reload it at a later date. If the selection has sharp edges, you will probably save it as a vector path. In the Paths panel (Window – Paths), choose Make WorkPath from the panel menu. If you may want the selection to contain feathering and other soft edge effects, you are best to save it as an alpha channel. To do this, simply choose Save Selection from the Select menu.

There can be many reasons why one may need to make selections in an image. Perhaps we want to cut out a product or person and place them on a different background. Perhaps we want to blur part of an image to add emphasis to the remainder.

Photoshop recognises the selection itself as a separate element which can be manipulated independently of the pixels it includes. Selections almost make you forget the absence of objects within bitmapped images. Once part of an image is selected, it can be targeted and manipulated in such a way that the pixels inside the selection can almost be treated as an object.

Making selections is often a painstaking operation; and so Photoshop allows you to build selections gradually and contains a number of sophisticated tools for modifying them. One of the simplest techniques is to add to or subtract from an existing selection. This can be done either by using modifier keys (hold down Shift to add or Alt to subtract) or by clicking on icons to enter Add or Subtract mode. Any selection made using one of these methods will take into account the pixels that are already selected.

Having mastered these basic techniques, you will find that selections become less like hard work. Photoshop is extremely consistent in the use of modifiers, so it doesn’t matter which selection tool you are using, the same techniques are always used for adding to and subtracting from a selection.

Adobe Photoshop’s native file format is “.psd”. This is the only format which supports all of Photoshop’s features: layers, layer masks, layer comps, etc. If you have used these features in creating your final artwork, it is always a good idea to retain the “.psd” version and use File – Save As to export your work in any other format.

When exporting images from Photoshop, you will normally either be targeting print or web graphics. Print graphics are saved in the CMYK colour space while web graphics remain in Photoshop’s native colour space: RGB. With print graphics the focus is on quality, while the main talent of web graphics formats is file compression.

TIFF (Tagged Image File Format) and the CMYK colour space are the standard when exporting work for print. Although the TIFF format is capable of preserving layers, best practice is to make sure that you flatten the image by choosing Layers – Flatten Image before exporting. EPS (Encapsulated PostScript) is another option for exporting files for print. However, this option is now normally reserved for files that contain one or more spot colours.

GIF (Graphic Interchange Format) and JPEG (Joint Photographic Experts Group) are the two main formats used for exporting web graphics. The GIF format compresses files by reducing the number of colours in an image. This makes the format ideal for exporting images that contain flat colour such as logos, charts and symbols. If photographs or images containing smooth transitions of colour are saved in GIF format, posterization and banding will normally occur. This is where, instead of seeing all the colours that were in the image, we see simplified clumps or bands of colour.

The JPEG format reduces file size by dividing the image into blocks of 8 x 8 pixels and locating redundant information within these blocks and rewriting the information in a simplified manner which requires less data storage. The fact that the human eye does not detect slight changes in colour means that pixels which have very similar colour values can be treated as being identical. When saving an image in the JPEG format, Photoshop allows you to specify the degree of compression. Naturally, there is always some loss of quality, so it is never a good idea to open a JPEG, make changes to it and then resave it. It is always better to fall back on the original PSD file if changes need to be made.