INTRODUCTION TO PHOTOSHOP
What is PhotoShop ?
Adobe PhotoShop is the most popular image editing application available for use on Macintosh and windows based computer systems. PhotoShop takes the image editing market up to 80%, compared to the other available systems.
PhotoShop enables the user to
Most of the tools found in PhotoShop is fully customizable, its more or less like having access to infinite amount of pencils, pastels, airbrushes, watercolors, and so on, all of which are certainly erasable.
Painting programs
Image editors fall into large software category of painting programs. In painting program you can draw line and the application convert into tiny squares dots called pixels. The painting itself is called bitmapped image. Logic behind is that each pixel convert to one byte.
Advantages of painting programs
Disadvantages of painting programs
Drawing programs
The drawing programs consist of objects, which are independent, and they are mathematically defined lines and shapes. For this reason they are said to be object oriented. Some preferred to call they as vector based. Adobe illustrator is a drawing programs.
In drawing program the term constructing can be used, because you actually build lines and shapes point by point and stack them on top of each other to create a finished image. Each object is independently editable.
Advantages of drawing programs
Disadvantages of drawing programs
When to use PhotoShop?
THE PHOTOSHOP DESKTOP
Introduction to:
Image windows
Like any windows package, PhotoShop allows you to open multiple windows at a time. Each opened window resides inside its own window.
You can cycle through open image by pressing CTRL+TAB
Status bar
Which provides the running commentry on the active tool and image. Use Windows menu, show status bar to activate it. Left end of the status bar indicates two boxes. Magnification box shows the current view size, and preview box shows the how much room it has taken in the memory.
Toolbox
Tools box contain all necessary tools for drawing, which contains 46 tools and 20 of them are visible. Lower end of the tool bar contains three sets of controls, color control, mask control, image windows control.
Preview box
More or less this can be called information box. By clicking the arrow key next to the preview box can be used to select the category of the information that need to be view, which are given bellow
The document size:- By default preview box contains two numbers divided by slash. The first number is the size of the base image memory. The second number takes into account any additional layers in your memory. First number is calculated by multiplying the height and width with the bit depth. For example if you have 320 pixels wide 200 pixels height and 24 bit image. Then you will have a value of 192K in your first box where 24 bits are converted to 3 bytes. Second value accounts for the real amount of memory required. Theoretically if the image has only one layer both values will be same. But virtually impossible to predict the second value since system uses compression methods and use other information associated with it such as spot color channels, unloadables, miscellaneous data etc.
Image position:- Click and hold the image window which indicates a popup box which shows the position of the image in the printed paper.
With ALT mouse down can be used to display the size and the resolution of the image.
With CTRL mouse down can be used to calculate the tile size of the image.
Memory consumption and availability:- When you select the scratch size, PhotoShop change the value in the preview box to indicate the amount of memory used divided by a slash and amount of memory available in the system. To program to run at its maximum efficiency the first value has to be smaller then second. (If multiple number of undos used, first number can be grown over the second number). If the first value is larger than the second value the PhotoShop has to swap extra amount of information to hard drive, which will considerably slow down the application. Following operations can be done to increase the memory availability.
Operating efficience:- This indicate the amount of time that PhotoShop wasted swapping information back and forth to hard drive. The best case is 100%, where no virtual memory is used. If the value is bellow 75%, either one of the four steps given before need to be used to increase the efficiency.
Clocking PhotoShop:- If the timing is selected, the preview box tells how long it took to finish the last operation.
The active tool:- If the tool option is selected then the preview box indicates the current tool in use.
Floating palettes
Palettes menu allow you to do tasks similar to tool box but the tasks are more less configuration tasks. Use Shift and click on the palettes title bar to align the palette to far left. Palettes can be activated from the window menu when required.
Shift + Tab can be used to hide or unhide the palettes. Panel of the palette can be dragged out as user preferred to customized the palette or merged to produced one palette box.
NAVIGATING IN PHOTOSHOP
The View Size
The user can change the size at the image appears in the screen. So you can see more of the image or concentrated a large image into small area. Each changes in the view is expressed as zoom ratio, which is the ratio between screen pixels and image pixels. 100% zoom ratio indicates one image pixel for each screen pixel, which is same as 1:1. A 200% image ratio doubles the size of the image pixels on the screen, and so on.
Actual Pixels
This is the 100% zoom ratio, where the image can be seen as it really is, with out a trace of screen distortion. This can be set by
Fit On Screen
PhotoShop use this to fit the image into a window either by reducing or increasing the size of the window. This can be set by
Print Size
This will show on the screen at the size that it will be printed on paper. Normally PhotoShop assumes the monitor displays exactly 72 pixels per inch. This may vary according to the monitors that you choose. To see the size of the printed image
Print size can be predefined by setting the Image menu Image size option.
The Zoom Tool
The zoom tool work in the range of 1600% to 0.2%. Methods used
Creating A Reference Window
This is useful when you work with manified view of the image. To activate a reference window, select View menu New View.
Scrolling Inside The Window
Other than the scroll bars the standard way that is used in PhotoShop is to use keyboard.
PageUp Up one screen
Shift+PageUp Up slightly
PageDown Down one screen
Shift+PageDown Down slightly
Ctrl+PageUp Left one screen
Ctrl+Shift+PageUp Left slightly
Ctrl+PageDown Right one screen
Ctrl+Shift+PageDown Right slightly
Home To upper left corner
End To lower right corner
The Navigator Palette
You can move the view box in the navigator palette view box to see different areas of the image.
By holding down the CTRL button and click on the windows will zoom the windows to its maximum size.
Certain area can be zoom in the image by holding down the CTRL button and selecting or a dragging a certain area in the view box.
The color of the view box can be changed by setting the color option in the navigator palette menu.
CUSTOMIZING THE INTERFACE
Most of the general preferences can be found in File menu Preference then General or by CTRL+K. All the preferences configuration is stored under a file called "prefs.psp". If PhotoShop started acting funny its good idea to delete this file, where it will create this file and restore the factory defaults. If you do not want others to play with the preference settings, set read only permission on this file.
Preference panel contains 8 different categories, which are explained in detailed bellow.
General Preferences
Color picker:- Either this can be set to windows or PhotoShop. This works with foreground and background color control icons in toolbar.
Interpolation:- This works with Image menu Image Size. When you increase the size of the image, PhotoShop calculate the required pixels by using the following three methods.
Anti-alias PostScript:- PhotoShop allows the other Object Oriented programs to import graphics, cut and paste or drag and drop.
Export Clipboard:- PhotoShop allow to transfer a copy of the image to Operating Systems clipboard from its internal clipboard. Therefore that data can be transfer to another application.
Short Pantone Name:- To support the older printers which do not support new color pantone names.
Show Tool Tips:- Display the labels of the tools and other objects.
Beep When Done:- request PhotoShop to beep when an operation is completed which is indicated by progress window.
Dynamic Color Sliders:- Instruct the PhotoShop to preview color effect within the color bars.
Save Palette Locations:- PhotoShop remembers the location of the floating palette and the tool box from one lesion to another
Saving Files
Image Preview :- When a file is saved PhotoShop can be requested to save with the postage-stamp, so that you can view thumb nail before opening it. Preview appears in open dialog box. This should not be used with WEB graphics, which causes to increase the size of the file.
File Extension:- Should use lower case for the last three letters in the file, which maintains the computability with the other operating systems such as UNIX in WEB graphics
Include Composite Image With Layered Files:- This try to maintained the computability with other programs which can read PhotoShop files but do not understand the layered graphics, where PhotoShop saves an extra layer for them, which doubles the file size. TURN THIS OFF ALWAYS.
Display & Cursors
Color Channel in Color:- All the pixels will be converted to 8bit of color data.
Use System Palette:- (Only matters if you work with 8bit color monitor or graphic card) PhotoShop try to convert high color such as 16million color images to 256 color images.
Use Diffusion Dither:- (Only matters if you work with 8bit color monitor or graphic card) This will try to enhances the pictures edges by using a natural diffusion.
Video LUT Animation:- (Only matters if you work with 8bit color monitor or graphic card) Required color correction is taken care.
Painting Cursors/Other Cursors:- Let you select the brush size
Transparency & Gamut
Transparency Settings:- Photoshop images resides on layers of total transparency. When you view layers independently from others, PhotoShop shows the fill through section with the check boxes. The color and the size of the check boxes can be set over here.
Gamut Warning:- If selected color can not be printed, Percentage of gray can be set to be displayed on screen to identify those places. From View menu select Gamut Warning to see this in the image. If you do not want it to be printed in Gray scale, reduce it to 10% or less.
Units & Rulers
Rulers:-Desired measurement can be set. Recommended to set to Pixels
Column Size:- Enable you to set to desired size for the grid
Point/Pica Size:- For traditional printer to set the number points that found in a inch. Always use default.
Guides & Grid
Guides:- Set a color to the ruler
Grid:- Set a color to grid lines
Plug-ins & scratch Disk
Plug-ins:- If you change the plug in folder, indicate PhotoShop where to find them.
Scratch disk:- If computer has more that one had drive, PhotoShop can be given the access to store its temporary information from memory to desired drives, to increase the efficiency. This has to be any drive other than the working drive. Setting will not be taken into effect ntill next time you load PhotoShop
Memory & Image Cache
PhotoShop keeps the image in the memory including different sizes, if color correction or some other method is applied, it will be applied to all and can be viewed at any size. Cache size has to be change according to memory availability. For example, if you have only 64Mb then it has to be set to 4, and 128Mb for 8 so on. This number indicates the number of images which will be caches.
The Physical memory usage value has to be set to less than 100%, if the user is desired to run other applications along the photo shop. If the PhotoShop is the only appellation which runs, then this can be set to 100% indicating that total memory will be given to PhotoShop.
Annotating an Image.
User File menu File Info to select this option, where you can put copy right as well as references to the designed image.
SCRIPTS
Scripting is the most powerful tool that is given in PhotoShop, where you can automate you tasks, or do batch processing. A script can be written and apply to a folder full of files.
Recording A Script
Use Windows menu Show Action to invoke action palette, which allow you to record and manage your recorded scripts. A script allows to record commands and are kept in form of sets or groups.
To record a script
To edit a script
Playing a script
Saving a set
Select the set or the group name. Then select Save action from palette menu. It will do nothing ordinary than sending it to disk. If you do not save it, it will be some how kept in the "prefs.psp" file. If this file get corrupted, you will lose all your scripts. Therefore its good idea to save them to different file.
Batch Processing
IMAGE FUNDAMENTALS
Size Versus Resolution
Size is the physical size of an image. Resolution is the number of pixels per linear inch. Number of pixels in an image is fixed. Therefore increasing the size of the image will decrease the resolution of the image. Higher resolution images gives sharper images with grater clarity.
Changing The Printing Resolution
From Image menu select Image Size and enter the required resolutions. Re-sampling Image should be unselected. Otherwise PhotoShop will add as well as subtract to reform the image to desired size. Constrain properties check box allow you to control each variable independently.
Resolution of Screen Image
Regardless of resolution and scaling value, PhotoShop displays each pixel on screen according to the zoom ratio. If zoom ratio is 100%, for example each image pixel takes up single screen pixel. This is same as doing CTRL+ALT+0. (Either you use Mac or windows, there is no difference, since same VGA standards are used in both the technologies.)
To Open an Existing Image
Select File menu Open and give the path to the image. (or CTRL+O). All image formats that PhotoShop recognize will be listed in open dialog box. If the file has lost its extension and user has knowledge of the file format user can use File menu Open As dialog box and selecting the correct format along the file.
File menu Import can be used to load images straight from scanners or Digital cameras. For this we need the required plug in for the PhotoShop. Certain cameras allow the user to check the pictures stored in the memory of the camera and allow the user to load the desired picture. To do this, required plug in need to be loaded first.
To Create A New Image
Select File menu New to create a new image from scratch. (or CTRL+N). Size, width and number of pixels per inch/centimeter need to be set. If color mode is selected either as Bitmap or Grayscale a black and white image will appear. RGB, CMYK and Lab colors can give up to 16 million colors with certain differences. The background color can be selected as white, current background color or transparent. If transparent is selected, no color will be set. Therefore it can be used as a layer. This type of images can not be saved other than native PhotoShop format. Therefore it has be flatten by using Layer menu flatten command.
Duplicating an Image
Image can be duplicated by selecting Image menu Duplicate. The same image will be duplicated and user will be able to later it with out affecting the main image. This is a good idea to save images with out affecting the original image. If the image contains multiple layers PhotoShop will ask user requires to merge layer to single visible layer.
Saving an Image to Disk
Image can be saved to disk by using File menu File As for firs time saving it. Afterwards its good idea to save the changes by using File menu Save command after every 10 to 15 minutes. (This can be done by CTRL+S) Saving a thumb nail with a image is a good idea, which allow you to preview it rapidly. Do not save a copy of thumbnail when you planning to do WEB postings, which will increase size of the image.
Save a Copy is a good idea to dump a copy of that image to disk, which will not alter the relation ship with the original image in the disk.
File Formats
The native Format PSD
This format is optimized for most of its capabilities and functions. This saves every attributes that you can apply in PhotoShop, including layers, extra channel info etc. This is the most efficient format that PhotoShop can work with.
Amiga’s IIF
This is failed format, developed by Commodore computers. Some Mac computers can recognized this format.
Microsoft Paint BMP
Used in Microsoft paint brush application. This format can recognized up to 16 million colors. Most common uses are to create wall papers for windows and images in help files.
ComputerServe’s GIF
This is the format used in WEB pages. This format is limited to 256 colors, and files can be highly compressed by using LZW argorithem.
PC Paintbrush PCX
Out dated format develop by paint brush package which is the oldest dos based painting packages. Can save up to 16 million colors. Most of the clip arts are saved in this format.
Adobe Paperless PDF
The Portable Document Format is a variation on postscript printing language that enables you to view electronically produced documents on screen. Using a package call Adobe acrobat Reader, you can view documents saved in this format. Find more documents in internet in this format, since this was the method developed for WEB browsing, but never became popular.
Apple’s PICT
Macintosh system software’s native graphics format based on QuickDraw package. This is the only file format which holds the bitmap as well as the object oriented file information equally.
Pixar Workstation Format
This is very common package which is used to 3D animated movies. PhotoShop allows the user to read as well as write to this format, after that can be used with Pixar Workstations.
PNG file type
This format use up to 16 million color to save with out compression. This format is ment to developed to be used in WEB. Neither Internet Explorer or Netscape Navigator use this format with out a plug-in.
Scitex Image-processors
This format is used to save the document in layered format for certain printers and scanners.
TrueVision’s TGA
TrueVision’s targa and NuVista video boards enable you to overlay computer graphics and animate them onto live video. The effect is called chroma keying, where the key color is set aside to let the live video show through.
EPS file type (Adobe Illustrator)
PhotoShop support the above object oriented file type which can be printed in any postscript printer. When this type of file is opened a Rasterize Option box is appeared and ask the user to convert the document to bitmap image. Its recommended to accept the default value or higher resolution rate. Anti-aliased check box need to be selected to blur the pixels to soften the image.
If you require EPS graphics into foreground image rather than placing it to background, use File menu Place command. After you import it do all necessary changes before rasterizing it to bitmap image. Double click on inside box or press enter key to rasterize the image.
When you saving it EPS format it will ask the screen preview method and the quality of the picture to be saved. It’s good idea to use encoding as Binary. Halftone Screen is the printing attribute, which can be set as defined in page setup dialog box. Transfer Function is the Brightness and Contrast of the screen can be saved with the file. Postscript Color management help the printer to define more accurate colors which is saved along EPS file. However EPS is very inefficient format.
QuarkXpress DCS
This is a modified version of EPS developed by QuarkXpress, which facilitates printing of color separation. Before you can save in DCS you have to convert the image to CMYK color space using Image menu Mode CYMK color.
Premiere Filmstrip
Adobe Premier is a popular QuickTime movie editing tool. This program is a wonder when it comes to frames, mergers, and special effects. These movie files can be edited PhotoShop in film strip format, after that they can be altered and saved into same format.
JPEG file format
Most popular file format in the WEB named after Joint Photographic Experts group. This is the most efficient and highly compression schemes it uses. But compression loses certain amount of image information.
When you try to save in JPEG format, a pop up window will appear and ask you to enter the quality value. To achieve maximum quality the value has to be close to 10 but consumes more disk space, and visa versa. Filed saved in JPEG format is not good for printing. JPEG works well with continuos-tone images (Images in which the distinction between immediately neighboring pixel is slight.)
TIFF file format
Developed by Aldus in the early days of the Macs to standardized scanned images. This is the most widely supporting printing file format. Compression is very powerful but not lossy as JPEG.
If you have limited RAM use can open isolated region of TIFF image by using File menu Import then Quick Edit. ( If this menu does not appear in the menu, this has to be installed from the Plug-in from PhotoShop installation CD)
Opening a RAW Document .raw.
This is uncompressed binary file, which contains image information. In this case width, height, number of channels, and bit depth has to be known in advance.
Resampling
Resampling means scaling the image, where it will contain larger or smaller number of pixels than the original image. Resampling will effect either size or resolution independently. (Resizing is enlarging the image but keeping the number of pixels same.) When resampling an image same method applied where resampling check box has to be selected. Resampling will increase or decrease number of pixels in the image by adding or subtracting.
Cropping
Another way to change number of pixels in an image is to crop it, which is to clip away pixels around the edges of an image without harming the remaining pixels. Cropping enables you to focus on an element in your image.
One way to crop an image is to choose Image menu Canvas size, where options in the dialog box allow you to scale the imaginary canvas which the image rests seperatly from the image itself.
Best way to do cropping is to use crop tool. To select the crop toll press "C" key.
After aligning it to correct place, either double click or press enter key to activate cropping. Crop can be activated from Image menu crop as well.
Information Palette can be used to gather the exact pixel location, color setting of a point on the image. To activate the information palette from Window menu select Show Info or press F8.
DEFINING COLORS
Foreground colors:- The colors that you apply when you use paint bucket, pensile, airbrush etc.
Background colors:-The back ground color applies when you use erase tool, or gradation created with gradient tool.
Using the Color Picker
When you double click on foreground or background color you will get color picker. Required colors can be selected for background or foreground by double clicking on the color. Required colors can be either selected from the slider of the values can be set in the text box according to the letter. Radio buttons are defined as seen in color picker.
H Hue up to 360O L Luminosity 0 to 100%
S Saturation up to 100% a Axes a -127 to 127
B Brightness up to 100% b Axes b -127 to 127
R Red 0 to 255 C Cyan up to 100%
G Green 0 to 255 M Magenta up to 100%
B Blue 0 to 255 Y Yellow up to 100%
K Black up to 100%
Slider represents 8 bit colors and the panel shows 16 bit colors, which eventually gives 16x65000 of 16 million colors.
Alert triangle will appear with a small color box to right of previous color boxes, which indicates that PhotoShop will not be able to print that color, it will show CYMK equivalent in that box.
Color Modes
Image menu Modes can be used to set the desired color.
RGB
RGB is the color mode of light, which comprise three primary colors of red, green and blue. In PhotoShop the intensity of each color can be set to 0 to 255 or 8 bit. RGB model is also called additive primary model, since color becomes lighter as you add higher level of primary colors. All monitors, televisions etc works with RGB principle. RGB mode displays wide range of colors some of them can not be printed. For best result in printing, image has be scanned in CMYK and all alterations has to be done in same mode.
HSB
Not widely used. Hue is pure color. Red is at 0, yellow at 60, green at 120, cyan at 180, blue 240, and magenta at 300. Saturation represents the purity of the color, a zero value equals to gray scale and full saturation is purest version of hue. Brightness is lightness or darkness of color.
CMYK
The is the color mode of the reflective paper. In nature our eyes perceive pigments according to the subtractive color model. Object absorb some of the light and reflect rest, such as fire brigade absorbs all the light except red.
In commercial printers three colors are mixed with black to form the complete color spectrum. Cyan absorbs only red light, Magenta absorbs green light, and Yellow absorbs blue light. If CMY is mixed together the output will be muddy brown. To get pure black we need black as well as to enhance the shadows and other dark places in printed image.
View menu Preview can be used to see how the CMYK print out will look like if you are using some other color mode. If necessary individual ink plates can be view, which will appear in gray scale. To view ink plate in exact color set the File menu Preferences, Display & Cursors, then select Color Channels in Color. If you are using CMYK for editing, there no need to worry about View menu Gamut warning.
Lab
This is the color mode which is most sensitive to human eyes. In lab luminosity is equivalent to HSB brightness. Channel "a" contains deep green to gray to pink. Channel "b" contains bright blue to gray to yellow. As RGB these colors mix to produce other colors. Device independent mode.
Grayscale
Grayscale will have all the picture information except color information. PhotoShop automatically use a algorithm to produce gray scale image. Useful to print color images in black and white.
Bitmap (Black & White)
This will allow only one bit images with lack of image information. Hardly any use. Only gray scale images can be converted.
Image menu Mode can be used to select above color methods. If you switch from RGB to CMYK the image will look duller due to certain bright colors will not be supported in CMYK mode. Caution should be taken if the color mode is set to bitmap or grayscale and saving the image, where the color information will not be able to restored easily.
Predefined Colors
If custom button is click inside the color picker dialog box, the custom colors will be displayed. Book popup menu contains other standard colors in use, but very uncommon in real world.
The Color Palette
The color palette is the other convenient way to set colors for foreground and background. To activate it select Windows menu Show colors. From the menu in the color palette desired color method can be set. The color bar has to be set separately.
The Swatches Palette
The swatches palette enables you to collect the desired color for future use.
The Eyedropper Tool
This tool can be activated by clicking it in tool bar or pressing I
Color Sampler Tool
Color sampler tool merely measures the colors of pixels so that users can monitor how the pixels reacts to various color changes. Select the Color sampler from toolbar, which sits next to eyedropper tool. Click anywhere in the image window to add that information to info palette, and Small cross hair will be added to image window. To remove it ALT+click on it. Use CTRL+drag it to desired location.