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Adobe Photoshop Ruler Guides and Grids

You can show a grid in your image window to help with alignment and measuring, and you can also drag in ruler guides from the rulers. Both sets of guides are non-printing, Customize the appearance of the grid and guides using Edit > Preferences > Guides & Grid.





1.To hide or show the grid. Choose view > show/hide grid.


2.To create a ruler guide, first choose view > show rulers to display the rulers along the top and left edges of the image window. Position your cursor in a ruler and then click and drag onto your image to create either a vertical or horizontal guide.

3.To reposition a ruler guide, select the Move tool, position your cursor on a guide, theb click and drag. The cursor changes to a bi-directional arrow when you pick up a guide. To remove a ruler guide, drag the ruler guide back into the ruler it came from. Alternatively, choose View > Clear Guides to remove all guides.


4. To temporarily hide any grid or guides in order to preview the image without the clutter of non-printing guides, choose View > Show Extras(Command/Ctrl+H). use the same command to bring back the guides and grid.

Adobe Photoshop Screen Environment

There are three ‘screen modes’ to choose from when working on images in Photoshop. The screen mode icons are located at the bottom of the toolbox. Full screen with Menu Bar mode is useful when working on individual images because it clears away the clutter of the Finder environment or the Windows desktop. Use Full Screen mode to see the image without the distraction of other screen elements, and without any other colours interfering with the colours in your image.

1.Click This Can to return to Standard Screen mode.

2.Click this icon to go to Full Screen With Menu Bar Mode.

3. Click this icon to go to Full Screen Mode. Press the tab key to hide/shoe the Toolbox and Palettes.

Colour Management

No two devices that represent colour, from scanner to monitor to printer, will reproduce colour in exactly the same way. The aim of a color management system is to ensure, as far as possible, that the colors you see on your screen will be as close as possible to the colors you see in the finished work, whether in print or on screen.

Color management settings are available so that you can choose a color management workflow most suitable for your needs.

Using the color settings dialogue box you can define how you manage color in your images as you work in Photoshop.

1.To specify color management settings for your Photoshop working environment. Launch photoshop, then choose Edit > Color Settings (Ctrl + Shift + K).
2.Choose the most appropriate setting for your intended final output from the settings pop-up list. For example, if you are using Photoshop for images that will be used in multimedia presentations, or on the World Wide Web, choose web graphics defaults. If you are working with images that will be color separated then printed using CMYK inks, choose Europe or US Prepress Defaults as appropriate.
3.Leave the advanced Mode option deselected unless you need to change one of the advanced settings.



4.Only make changes to the default settings when you have gained experience of using Photoshop and you have a valid reason for making changes, or if you have consulted with your commercial printer and they have suggested changes to suit your specific output requirements.
5.To get a better understanding of how the settings work in the color settings dialogue box, roll your cursor over the pop-up lists. The description area at the bottom of the palette updates with information on how the options affect the image.

RGB and CMYK Colour Models

As you start working with Adobe Photoshop there are two colour models that you need to be aware of. These are the RGB(Red, Green, Blue) and CMYK (Cyan, Magenta, Yellow and Black) colour models.

RGB is important because it mirrors the way the human eye perceives colour. It is the model used by scanners and digital cameras to capture colour information in digital format, and it is the way that your computer monitor describes colour.

Red, green and blue are referred to as the ‘additive primaries’. You can add varying proportions of the three colours to produce millions of different colours – but still a more limited range (or ‘gamur’) than in nature, due to the limitations of the phosphor screen coating of the monitor. If you add 100% red, green and blue light together, you get white. You produce the ‘secondary’ colours when you add red and blue to get magenta; green and blue to get cyan; red and green to get yellow.

The CMYK colour model is referred to as the ‘subtractive’ colour model. It is important because this is the colour model used by printing presses. If you subtract all cyan, magenta and yellow when printing you end up with the complete absence of colour – white.

Pixels and Resolution

Pixels
A pixel is the smallest element in a bitmap image such as a scan. Pixel is short for ‘picture element’. Zoom in on an image in Photoshop and you will start to see the individual pixels- the fundamental building blocks – that make up the image. When working in Photoshop, you are editing pixels, changing their colour, shade and brightness.

Resolution
A key factor when working on bitmap images is resolution. This is measured in pixels per inch (ppi).

Pixels can vary in size. If you have and image with a resolution of 100 ppi, each pixel would be 1/100th of an inch square. In an image with a resolution of 300 ppi, each pixel would be 1/300th of an inch square – giving a much finer, less blocky result.

When working on images that will eventually be printed on a printing press, you need to work on high-resolution images. These are scanned images whose resolution is twice the halftone screen frequency (measured in lines per inch – lpi) that will be used for final output – that is when you output to bromide or film.

For example, for a final output screen frequency of 150 lpi – a typi8cal screen frequency used for glossy magazines – you need to scan you image at a resolution of 300 ppi.

Resolutions of double the screen frequency are important for images with fine lines, repeating patterns or textures. You can achieve acceptable results, especially when printing at screen frequencies greater than 133 lpi, using resolutions of 11/2 times the final screen frequency.

To work with images for positional purposes only, as long as you can get accurate enough on-screen results and laser proofs, you can work with much lower resolutions.

Bitmaps and bit-depth

An important factor when the digital data for an image is captured, typically at the scanning stage, is its bit-depth. Bit-depth refers to the amount of digital storage space used to record information about the colour of a pixel. The more bits you use, the more colour of a pixel-but also, the larger the file size you end up with.

To output realistic images using PostScript technology an image should be able to represent 256 grey levels. A 24-bit scan is sufficient for recording 256 grey levels for each of the Red, Green and Blue channels, resulting in a possible combination of over 16 million colours.

Ideally, when you work on images in Photoshop you will do so using a 24-bit monitor capable of displaying over 16 million colours. This ensures that you see all the colour detail in the image. Although you can work on images using only thousands of colours, for best results, especially where colour reproduction is important, you need to work with as many colours as possible.

Bitmaps and Vectors

Photoshop is an image-editing application with of tools and commands for working on digital images or bitmaps. there are ultilities for retouching, colour correcting, compositing and more. There are also over 90 functional and creative filters that can be applied to entire images, or selected areas within images.

A bitmap image consists of a rectangular grid, or raster, of pixelsin concept, very much like a mosaic. when you edit a bitmap you are editing the colour values of individual pixels or group of pixels.

Image-editing applications differ fundamentally from vector-based applications such as
Adobe Illustrator and Macromedia Free Hand. In these applications, you work with objects that can be moved, In these applications, you work with objects that can be moved, scaled, transformed, stacked and deleted as individual or grouped objects, but all the time each exists as a complete, separate object.

These applications are called vector drawing packages, as each object is defined by a mathematical formula. Because of this, they are resolution-independent-you can scale vector drawings up or down (either in the originating application or in a page layout application such as QuarkXPress or Adobe Page Maker) and they will still print smoothly and crisply.

In contrast, bitmaps are created at a set resolution-a fixed number of pixels per inch. If you scan an image at a specific resolution (unless you add more pixels). You are likely to end up with a blocky, jagged image, as you have increased the size of the individual pixels that make up the bitmap image.

NOTE- You should always try to scan an image at, or slightly larger than, the size at which you intend to use it. This means you will avoid having to increase the size of the image.

Photoshop Tools > Pen Tool

1.Pen Tool(P)
The pen tool lets you create straight lines and smooth flowing curves with greater precision than is possible with the freeform pen tool. For most users, the pen tool provides the best control and greatest accuracy for drwaing.


2.Add Anchor Point Tool
The add anchor point tools let you add points on a shape.



3.Delete Anchor Point Tool(P)
The Delete anchor point tools let you delete points on a shape.



4.Convert Point Tool
The convert point tool lets you convert a smooth curve to a sharp curve or to a straight segment.



5.Freeform Pen Tool
The freeform pen tool lets you draw as if you were drawing with a pencil on paper. Anchor points are added automatically as you draw. You do not determine where the points are positioned, but you can adjust them once the path is complete