Adobe Photoshop

Photoshop was created in 1988 by Thomas and John Knoll. Since then, it has become the de facto industry standard in raster graphics editing, such that the word "photoshop" has become a verb as in "to Photoshop an image," "photo shopping," and "photoshop contest," etc. It can edit and compose raster images in multiple layers and supports masks, alpha compositing and several color models including RGB, CMYK, Lab color space, spot color and duotone. Photoshop has vast support for graphic file formats but also uses its own PSD and  PSB file formats which support all the aforementioned features. In addition to raster graphics, it has limited abilities to edit or render text, vector graphics (especially through clipping path), 3D graphics and video. Photoshop's featureset can be expanded by Photoshop plug-ins, programs developed and distributed independently of Photoshop that can run inside it and offer new or enhanced features.

Photoshop's naming scheme was initially based on version numbers. However, in October 2002, following the introduction of Creative Suite branding, each new version of Photoshop was designated with "CS" plus a number; e.g., the eighth major version of Photoshop was Photoshop CS and the ninth major version was Photoshop CS2. Photoshop CS3 through CS6 were also distributed in two different editions: Standard and Extended. In June 2013, with the introduction of Creative Cloud branding, Photoshop's licensing scheme was changed to that of software as a service and the "CS" suffixes were replaced with "CC". Historically, Photoshop was bundled with additional software such as Adobe ImageReady, Adobe Fireworks, Adobe Bridge, Adobe Device Central and Adobe Camera RAW.

Alongside Photoshop, Adobe also develops and publishes Photoshop Elements, Photoshop Lightroom,Photoshop Express and Photoshop Touch. Collectively, they are branded as "The Adobe Photoshop Family". It is currently a licensed software.

Early History

Photoshop was developed in 1987 by the American brothers Thomas and John Knoll, who sold the distribution license to Adobe Systems Incorporated in 1988.Thomas Knoll, a PhD student at the University of Michigan, began writing a program on his Macintosh Plus to display grayscale images on a monochrome display. This program, called Display, caught the attention of his brother John Knoll, an Industrial Light & Magic employee, who recommended that Thomas turn it into a full-fledged image editing program. Thomas took a six-month break from his studies in 1988 to collaborate with his brother on the program. Thomas renamed the program ImagePro, but the name was already taken. Later that year, Thomas renamed his program Photoshop and worked out a short-term deal with scanner manufacturer Barneyscan to distribute copies of the program with a slide scanner; a "total of about 200 copies of Photoshop were shipped" this way.

During this time, John traveled to Silicon Valley and gave a demonstration of the program to engineers at Apple and Russell Brown, art director at Adobe. Both showings were successful, and Adobe decided to purchase the license to distribute in September 1988. While John worked on plug-ins in California, Thomas remained in Ann Arbor writing code. Photoshop 1.0 was released on 19 February 1990 for Macintosh exclusively. The Barneyscan version included advanced color editing features that were stripped from the first Adobe shipped version. The handling of color slowly improved with each release from Adobe and Photoshop quickly became the industry standard in digital color editing. At the time Photoshop 1.0 was released, digital retouching on dedicated high end systems, such as theSciTex, cost around $300 an hour for basic photo retouching.

File Format

Photoshop files have default file extension as .PSD, which stands for "Photoshop Document." A PSD file stores an image with support for most imaging options available in Photoshop. These include layers with masks, transparency, text, alpha channels and spot colors, clipping paths, and duotone settings. This is in contrast to many other file formats (e.g., .JPG or .GIF) that restrict content to provide streamlined, predictable functionality. A PSD file has a maximum height and width of 30,000 pixels, and a length limit of 2 Gigabytes.

Photoshop files sometimes have the file extension .PSB, which stands for "Photoshop Big" (also known as "large document format"). A PSB file extends the PSD file format, increasing the maximum height and width to 300,000 pixels and the length limit to around 4 Exabytes. The dimension limit was apparently chosen arbitrarily by Adobe, not based on computer arithmetic constraints (it is not close to a power of two, as is 30,000) but for ease of software testing. PSD and PSB formats are documented.

Because of Photoshop's popularity, PSD files are widely used and supported to some extent by most competing software. The .PSD file format can be exported to and from Adobe's other apps like Adobe Illustrator, Adobe Premiere Pro, and After Effects, to make professional standard DVDs and provide non-linear editing and special effects services, such as backgrounds, textures, and so on, for television, film, and the Internet. Photoshop's primary strength is as a pixel-based image editor, unlike vector-based image editors. Photoshop also enables vector graphics editing through its Paths, Pen tools, Shape tools, Shape Layers, Type tools, Import command, and Smart Object functions. These tools and commands are convenient to combine pixel-based and vector-based images in one Photoshop document, because it may not be necessary to use more than one program. To create very complex vector graphics with numerous shapes and colors, it may be easier to use software that was created primarily for that purpose, such as Adobe Illustrator or CorelDRAW. Photoshop's non-destructive Smart Objects can also import complex vector shapes.

Plugins

Photoshop functionality can be extended by add-on programs called Photoshop plugins (or plug-ins). Adobe creates some plugins, such as Adobe Camera Raw, but third-party companies develop most plugins, according to Adobe's specifications. Some are free and some are commercial software. Most plugins work with only Photoshop or Photoshop-compatible hosts, but a few can also be run as standalone applications.

There are various types of plugins, such as filter, export, import, selection, color correction, and automation. The most popular plugins are the filter plugins (also known as a 8bf plugins), available under the Filter menu in Photoshop. Filter plugins can either modify the current image or create content. Below are some popular types of plugins, and some well-known companies associated with them:

• Color correction plugins (Alien Skin Software, Nik Software, OnOne Software, Topaz Labs Software, The Plugin Site, etc.)
• Special effects plugins (Alien Skin Software, Auto FX Software, AV Bros., Flaming Pear Software, etc.)
• 3D effects plugins (Andromeda Software, Strata, etc.)

Adobe Camera Raw (also known as ACR and Camera Raw) is a special plugin, supplied free by Adobe, used primarily to read and process raw image files so that the resultant images can be processed by Photoshop. It can also be used from within Adobe Bridge.

Photoshop Tools

Pen tool :- Upon loading Photoshop, a sidebar with a variety of tools with multiple image-editing functions appears to the left of the screen. These tools typically fall under the categories of drawing; painting; measuring and navigation; selection; typing; and retouching.Some tools contain a small triangle in the bottom right of the toolbox icon. These can be expanded to reveal similar tools. While newer versions of Photoshop are updated to include new tools and features, several recurring tools that exist in most versions are discussed below.

Photoshop includes a few versions of the pen tool. The pen tool creates precise paths that can be manipulated using anchor points. The free form pen tool allows the user to draw paths freehand, and with the magnetic pen tool, the drawn path attaches closely to outlines of objects in an image, which is useful for isolating them from a background.

Shape tools

Photoshop provides an array of shape tools including rectangles, rounded rectangles, ellipses, polygons and lines. These shapes can be manipulated by the pen tool, direct selection tool etc. to make vector graphics.

Measuring and navigation

The eyedropper tool selects a color from an area of the image that is clicked, and samples it for future use. The hand tool navigates an image by moving it in any direction, and the zoom tool enlarges the part of an image that is clicked on, allowing for a closer view.

Selection tools

Selection tools are used to select all or any part of a picture to perform cut, copy, edit, or retouching operations.

Cropping

The crop tool can be used to select a particular area of an image and discard the portions outside the chosen section. This tool assists in creating a focus point on an image and excluding unnecessary or excess space. Cropping allows enhancement of a photo’s composition while decreasing the file size. The "crop" tool is in the tools palette, which is located on the right side of the document. By placing the cursor over the image, the user can drag the cursor to the desired area. Once the Enter key is pressed, the area outside the rectangle will be cropped. The area outside the rectangle is the discarded data, which allows for the file size to be decreased. The "crop" tool can alternatively be used to extend the canvas size by clicking and dragging outside the existing image borders.

Slicing

The "slice" and slice select tools, like the crop tool, are used in isolating parts of images. The slice tool can be used to divide an image into different sections, and these separate parts can be used as pieces of a web page design once HTML and CSS are applied. The slice select tool allows sliced sections of an image to be adjusted and shifted.

Moving

The move tool can be used to drag the entirety of a single layer or more if they are selected. Alternatively, once an area of an image is highlighted, the move tool can be used to manually relocate the selected piece to anywhere on the canvas.

Marquee

The marquee tool can make selections that are single row, single column, rectangular and elliptical. An area that has been selected can be edited without affecting the rest of the image. This tool can also crop an image; it allows for better control. In contrast to the crop tool, the "marquee" tool allows for more adjustments to the selected area before cropping. The only marquee tool that does not allow cropping is the elliptical. Although the single row and column marqueetools allow for cropping, they are not ideal, because they only crop a line. The rectangular marquee tool is the preferred option. Once the tool has been selected, dragging the tool across the desired area will select it. The selected area will be outlined by dotted lines, referred to as "marching ants". These dotted lines are called "marching ants", because the dashes look like ants marching around the selected area. To set a specific size or ratio, the tool option bar provides these settings. Before selecting an area, the desired size or ratio must be set by adjusting the width and height. Any changes such as color, filters, location, etc. should be made before cropping. To crop the selection, the user must go to image tab and select crop.

Lasso

The lasso tool is similar to the "marquee" tool, however, the user can make a custom selection by drawing it freehand. There are three options for the "lasso" tool – regular, polygonal, and magnetic. The regular "lasso" tool allows the user to have drawing capabilities. Photoshop will complete the selection once the mouse button is released. The user may also complete the selection by connecting the end point to the starting point. The "marching ants" will indicate if a selection has been made. The "polygonal lasso" tool will draw only straight lines, which makes it an ideal choice for images with many straight lines. Unlike the regular "lasso" tool, the user must continually click around the image to outline the shape. To complete the selection, the user must connect the end point to the starting point just like the regular lasso tool. "Magnetic lasso" tool is considered the smart tool. It can do the same as the other two, but it can also detect the edges of an image once the user selects a starting point. It detects by examining the color pixels as the cursor move over the desired area. A pixel is the smallest element in an image. Closing the selection is the same as the other two, which should also should display the "marching ants" once the selection has been closed.

The quick selection tool selects areas based on edges, similarly to the magnetic lasso tool. The difference between this tool and the lasso tool is that there is no starting and ending point. Since there isn’t a starting and ending point, the selected area can be added onto as much as possible without starting over. By dragging the cursor over the desired area, the quick selection tool detects the edges of the image. The "marching ants" allow the user to know what is currently being selected. Once the user is done, the selected area can be edited without affecting the rest of the image. One of the features that makes this tool especially user friendly is that the SHIFT key is not needed to add more to the selection; by default, extra mouse clicks will be added to the selection rather than creating a new selection.

Magic wand

The magic wand tool selects areas based on pixels of similar values. One click will select all neighboring pixels of similar value within a tolerance level set by the user. If the eyedropper tool is selected in the options bar, then the magic wand can determine the value needed to evaluate the pixels; this is based on the sample size setting in the eyedropper tool. This tool is inferior to the quick selection tool which works much the same but with much better results and more intuitive controls. The user must decide what settings to use or if the image is right for this tool.

Eraser

The Eraser tool erases content based on the active layer. If the user is on the text layer, then any text across which the tool is dragged will be erased. The eraser will convert the pixels to transparent, unless the background layer is selected. The size and style of the eraser can be selected in the options bar. This tool is unique in that it can take the form of the paintbrush and pencil tools. In addition to the straight eraser tool, there are two more available options – background eraser and magic eraser. The background eraser deletes any part of the image that is on the edge of an object. This tool is often used to extract objects from the background. The magic eraser tool deletes based on similar colored pixels. It is very similar to the magic wand tool. This tool is ideal for deleting areas with the same color or tone that contrasts with the rest of the image.

Video editing

In Adobe CS5 Extended edition, video editing is comprehensive and efficient with a broad compatibility of video file formats such as MOV, AVI, MPEG-4, and FLVformats and easy workflow. Using simple combination of keys video layers can easily be modified, with other features such as adding text and the creation of animations using single images.

3D extrusion

With the Extended version of Photoshop CS5, 2D elements of an artwork can easily become three-dimensional with the click of a button. Extrusions of texts, an available library of materials for three-dimensional, and even wrapping two-dimensional images around 3D geometry.

Mobile integration

Third-party plugins have also been added to the most recent version of Photoshop where technologies such as the iPad have integrated the software with different types of applications. Applications like the Adobe Eazel painting app allows the user to easily create paintings with their fingertips and use an array of different paint from dry to wet in order to create rich color blending.

Camera Raw

With the Camera Raw plug-in, raw images can be processed without the use of Adobe Photoshop Lightroom, along with other image file formats such as JPEGs,TIFFs, or PNGs. The plug-in allows users to remove noise without the side-effect of over-sharpening, add grain, and even perform post-crop vignetting.

3D printing tools

Requiring Photoshop version 14.1 or later, users can create and edit designs for 3D printing. After downloading 3D photo models from numerous online services, users can add color, adjust the shape or rotate the angles. Artists can also design 3D models from scratch.

Color replacement tool

The Color Replacement Tool allows you to change the color, while maintaining the highlights and shadows of the original image, of pieces of the image. By selecting Brushs and right clicking, the Color Replacement Tool is the third option down. What is important to note with this tool is the foreground color. The foreground color is what will be applied when painting along the chosen part of the image with the Color Replacement Tool.