- 1 Introduction
- 2 Interface
- 3 Getting started
- 4 The toolbox
- 5 Editing images
- 6 Applying the techniques
- 7 Image filtering
- 8 Adjusting and repairing images
- 9 Further Reading
Before you start reading this page, make sure you have a basic understanding of what Photoshop is and what the main differences are between Pixels and Vectors. This information is available in the Main Photoshop article.
This article covers the main features of Photoshop and briefly explains how they can be used.
The Photoshop interface contains 4 important fields. In the first field you will find the pull-down menu. This field is also called the menu bar. Here you can find the usual commands.
- opening, saving and closing files en the print settings.
- undo, copy, paste, scale and rotate parts of the image.
- important menu for adjusting the image color, -brightness, and the size of the image and the canvas
- all layer settings and functions.
- selection options
- filters allow you to change the image using all kinds of effects
- menu with settings for viewing the image. Here you can zoom in/out and turn on/off rulers and grid
- Indicates and lets you turn on/off different sub menus.
The toolbox is located on the left side. It contains the main tools like selection, drawing and navigation tools.
A set of menus is located on the right side of the screen. Here you find functions concerning navigation, undo options, color selection and layers. The layer menu will be used very often.
Between all menus and the toolbox is the white canvas. All adjustment take place on this canvas. The size of the canvas can be altered in the pull down menu . The measurements can be indicated in for example pixels and percentages. The anchor functions determines where the existing canvas will remain relative to the expanded part.
In the drop down menuyou can select the location of an existing file you want to open. Photoshop can open primarily Raster images. Vector images can be converted to raster images or become 'smart objects' in Photshop.
Starting a new file
You can create a new file form the menu bar under(ctrl-N). When you do this, a menu automatically opens for choosing the absolute amount of pixels (for example 640 *480) or the print size in DPI. Both values can be changed afterwards under .
Saving a file
In the drop down menuyou can save your file. Choosing Save saves your file under its current name and in its current location. If you just started a new file and have not saved before, Photoshop will ask you where, in which format, and under which name you want to save. With the Save As option you can save a copy of an existing file under a different name and extension. If you are saving files for internet publication, use the Save for Web option. This opens a menu where the quality can be adjusted. Save for Web drastically decreases file size, but may also decrease image quality.
In the toolbox we can find the tools which are often used when working with Photoshop. This toolbox is divided in basically 4 sections. In these sections we can find related tools. We won’t explain them all, only the most used tools. If a tool is not explained in this manual you can access the Photoshop help files. All the tools have similar properties in their handling in the interface:
- Hovering over the tool will open a description of the tool.
- Some of the tools have a small arrow at the right bottom of the icon. This arrow tells us there are additional tools connected to the icon. If the arrow is clicked the additional tools become visible.
- If a tool is activated additional the setting become available in the Pull down menu bar. Some of these options can also be accessed by right clicking when the tool is active.
The tools in the toolbox
The selection option in Photoshop is used to localize the effect of image editing or to cut out parts of the image. Although a part of the image is selected, the editing of that part is only effective in the active layer. The selection can be drawn in free , fixed form or by using the magic wand. The last option selects a color range which can be adjusted by altering the settings in the menu bar. In the pull down menu bar there is a separate section on selection options which demonstrates its importance in editing images. Although most of the selection options in the pull down menu speak for themselves a few must be mentioned.
To add to a selection press SHIFT to subtract from a selection press ALT
- Color Range
- selects parts of an image with the same color, the range can be extended. Often used to make a “soft selection” for example to change the color tone of a single color.
- softens the edge of the selection. Often used when the image is locally adjusted by changing the brightness or color saturation for example. The soft edge of the selection prevents a clear visible border of the adjusted and non adjusted part of the image.
- adding a border to the selection . Making it possible to fill in the border and thereby drawing a line in stet of the border.
- Smooths out the selection edges- not the border between selected and non selected parts of the image!
- Expanding the selection
- Contracting the selection
- Transform selection
- makes it possible to modify the selection area without the need to reselect.
- Save selection
- Option of saving the selection for later use. If the selection has to be saved with the image for later use a PSD, TIFF or TGA format is needed.
- Load selection
- loading a saved selection. This is an effective option to not only use selections on different layers but is gives you also the option of using Alpha channels made during Maya rendering. This Alpha channel makes it possible to easily select the geometry of the Maya model in the image so backgrounds like clouds can be added with no effort.
There are a range of drawing tools available in Photoshop. Although it is possible to draw lines, the draw option is more often indirectly used in the editing of the image. The brush for example is often used to make parts of an layer transparent or opaque by painting the layer mask. The clone tool makes a copy of a part of the image and places it at another location by clicking of the mouse. Although it possible to make sketches within Photoshop the main task of the drawing tools is the support of the editing of the image. Specialized software like SketchBook Pro and Corels Painter are more suited for digital sketching as they support a whole range of different pencils and brushes.
The main drawing tools are:
- Brush tool
- The brush within Photoshop. When the tool is selected the settings become visible in the menu bar. There are a range of brushes available and the brush size can be manually altered independent of the selected brush.
- Clone Stamp Tool
- Very effective tool in making small copies of the image and place them in a different place. This tool is often used to repair artefacts in an image like transitions between two images.
- Paint bucket / gradient tool
- covers the selected area with one color or a gradient between two colors.
- Works like an eraser, locally deleting the information of the image. Be careful in using the eraser, the information is deleted and although Photoshop has an undo option the undo steps are limited. A more effective method of “erasing” image data is making it invisible. This will not delete the image but makes it transparent and if needed opaque again. This technique is explained in the Layer Mask section of this manual.
- Blur/sharpen Tool
- makes it possible to localize a blurring or sharpening effect in the image. Blur and sharpen can also be used on the whole image by using the pull down menu of Filter- Blur or Filter-Sharpen.
- Burn/Dodge Tool
- Localizes the effect of brightening or darkening the image. Always check the settings in the menu bar as they have a major effect on the tool. If this tool is applied it is recommended to make a copy of the part of the image where the tool will be applied. Problems with the limited undo and the large effect this tool has on the images makes it a tricky tool to use.
Vector drawing tools
Although Photoshop is a primarily a raster image editor there are some vector tools available. The vector tools make it possible to generate solid colored surfaces, lines and text. The advantage of the vector tools is that they the effect or drawing can be adjuster after they are used. They are resolution independent and especially with text it can be an advantage to have the text defined as a vector.
- Type Tool
- makes it possible to add text to the image and still be able to change the text, size and letter type afterwards.
- Rectangle Tool
- there are a few options of drawing vector surfaces in Photoshop. There is also a line tool with the option of adding an arrow at the end or/and at the beginning.
Because Photoshop only works with 2 dimensional images the navigating tools are limited to panning and zooming. Additional options are available when the zoom tool is selected and the mouse is right clicked. There is a limit op zooming in. The pixel structure becomes clear when is zoomed in on the image.
Introduction editing images
Raster image editing is the main function of Photoshop. It will allow the user to change, add or erase information of a raster image. It can be used to create complex compositions of combinations of different images, repairing artefacts in the image, erasing unwanted elements in the image and enhance the quality of the image in general. The tools which are available to change the content of the image are at this moment so powerful that it is increasingly difficult to see if a digital image is edited or not. There are 4 levels of image editing;
The actual content of the image isn’t changed. This option is used to enhance parts or the whole image. In this case the color and brightness/lightness information of the image is changed. An example is the adjustment of a digital photograph which was originally to dark, or the colors where of as the result of a wrong gamma setting on the digital camera. Extreme forms of changing the color or brightness/lightness of an image can generate quite alien images and can be used to generate an art like image.
The actual content of the image is adjusted. A good example is the current practice to edit advertisement photographs. Due to the high resolution of the images the slightest imperfections become visible, these imperfections are edited out of the image. This will create a perfect although unrealistic image. Parts of the image can also be erased, a technique which was in its analogue form used by dictatorships to erase party members from photographs who fell out of grace. The difference with the next level is that the content of the image itself is used to repair or alter the image, so no new images are introduced into the image. Although this sounds quite harmless, it is this gray area of image editing which blurs the lines between authentic and artificial.
The actual content of the image is adjusted by adding additional external image data. This technique enables the user to combine different images into one image. It will give the user the possibility for example to add or change backgrounds ,add or replace objects, people and trees and combine renders of virtual objects with digital photographs. The final image is a composition of different images and therefore doesn’t represent an true representation of the actual original image. This technique is especially interesting for people who want to combine different images together to simulate a photograph. The combination of the content isn’t real but it looks like it is real. Architects can use this technique to make photo montages of a render of the virtual model of the design and paste it in a photograph of the location. In the film industry this technique is used for so called Matte paintings, a technique for generating surrealistic and simulated backgrounds.
The actual content of the image is not altered but the appearance is changed. The filtering of images can be used to change the appearance of an image. The filters will add an effect to the image to generate for example an oil painting look to the image. These techniques can be used to match the appearance of the image with the purpose of the image. A concept design render of a building can be to realistic to be used for a presentation for the client. Filtering the image can remedy this problem.
Most of the times when an image is edited in Photoshop it is also adjusted to enhance the overall quality of the image. To get access to the adjustments options we go to the pull down menu. For now we'll only cover the most commonly used adjustment options. Refer to the Photoshop for the other options. You can also find out what they do by a little testing and playing around.
Menu for changing the brightness of your image. The level menu will show a graph representing the brightness distribution within the image. The left side of the graph represents the darkest parts of the image, the right site the brightest parts of the image. By sliding the arrows beneath the graph the brightness can be adjusted. The left arrow will make the image darker, the middle will shift the contrast/brightness of the image and the right arrow will make the image brighter. The color bar at the bottom of the menu is used for the lightness and darkness of the image. The difference with the brightness is that the value is uniformly applied, causing the image to become less crisp. Because there adjustments are previewed , the different settings can be easily checked on the image.
- Auto Level
- Automated setting for leveling the image. No settings are available. This option can be used to get an idea of the quality of the overall brightness distribution of the image. If it changes radically when the option is used, the option can be undone and the levels manually checked.
- Auto Contrast
- Automated setting for optimizing the contrast in the image. No settings are available. This setting can also be applied manually by using the Brightness/Contrast option. This option can be used to get an idea of the quality of the image. If it changes radically when the option is used, the option can be undone and the Brightness/Contrast manually checked.
- Auto Color
- Automated setting for changing the color saturation and hue of the image. No settings are available for this tool. The color and saturation can also be changed manually with the Hue/Saturation option. This option can be used to get an idea of the quality of the overall Hue/Saturation of the image. If it changes radically when the option is used, the option can be undone and the Hue/Saturation manually checked.
The curve option is a tool which changes the brightness and contrast of the image. The option is similar with the levels function, the difference is that with the curve option gives more control on the changes. The line at the bottom left represents the dark areas of the image, the right top represents the light part of the image. By changing the curve the brightness can be adjusted independently on different levels making it an effective tool for preventing glare effects and maintain the right contrast without generation white or black areas in the image. The line can be altered by clicking on it and dragging it to the right for darker and to the left for lighter.
The option color balance will give you access to the color properties of the image. The color sliders can be moved changing the color of the image. There are three options in the tone balance which have a fundamental effect on the function of the too. The tool can be used when the color tone is offset due to a wrong gamma setting of a digital camera for example.
The brightness contrast tool has a similar effects as the level and curve option. However the input is more straight forward it gives less control over these properties. The brightness and contrast can be separately accessed.
The hue saturation tool is used for changing the color information of the image. The hue option is used to shift the color spectrum of the image. This will cause the replacement of one color by another. Images which have an overall dominant color tone which should be there the alteration of the hue can give the image a more natural look. The saturation is the depth of the color and the lightness is the overall lightness of the image. The option of colorize can be used in combination with the hue to replace the color of the image with a single color.
The variations tool is a combination of various tools explained here. The tool gives a interface where the different alterations can be viewed and stepwise applied. Although the interface is user friendly the options are limited.
Applying the techniques
Applying these techniques is quite straight forward. It can be applied on the whole image or on a part of the image. There are different reasons why the adjustment could be necessary. Often it has to do with the different media types and different origins of the images which may require enhancement in Photoshop.
The most common problems of a digital photo are:
The image can be to dark or to light due to:
- Wrong shutter speed settings
- Aperture of the lens
- Wrong ISO value
- Wrong Gamma setting
- Extreme environment which can’t be compensated by the settings and properties of lens and camera.
If a digital image has to be adjusted to enhance the brightness or darkness of the image the following tools can be used in order of flexibility and functionality. The most effective tool for adjusting the brightness of an image:
- Brightness /contrast
- Auto levels
- Auto contrast
Images rendered in for example Maya. Unlike the brightness and color content of a digital photograph the quality of these properties in a render are influenced by the lighting and render setting. The settings of the standard virtual camera have little effect on the quality of the image. Although in some render engines real live properties of the camera can be added to influence the brightness and color of the image, most camera’s in the render engines are primarily used to define the field of view. This means that if a rendered image is to dark or to bright or the color is shifted, the render settings and the lights have to be adjusted. Common problems are:
Renders to dark
Light is not penetrating far enough into the space or in recesses in the geometry. If the render and light settings of the image have to be adjusted in the Rendering software, it can take more time to get the settings right and test render it than import the image in Photoshop en test if it can be enhanced. This will only work for relatively small lighting problems; avoid any absolute black or white areas in your image. These won’t contain any information of geometry only a solid color. Making these spots darker or lighter will only cause them to turn into gray. If there's no detail in the image whatsoever, it cannot be enhanced.
The curve option is the most effective in the enhancement of these images as it can avoid glaring and blackening of parts of the images while some brightness ranges can be adjusted.
Renders have a color haze
Often the result of a colored main light source like the sun or the hemisphere. Although Maya supports the coloring of the sun and hemisphere it should be applied very carefully. If a color is added the best thing to do is to assign a color temperature and not a solid color. The color temperature contains the right setting for the amount and depth of the color. If the image is colored to much anyway the image can be imported to Photoshop where the color can be adjusted. Keep in mind that changing the contrast in the image can also lead to a deeper and more saturated colored image. The most effective method is:
- Color balance
- Hue and saturation
- Auto color
Localize the adjustment
If only a part of the image has to be adjusted the select options will come into play. Besides the selection options in the toolbox there are selection tools available in the pull down menu Select. Especially when a certain color or brightness has to be adjusted the COLOR SELECT option is a powerful tool. The color selection can be picked or preset colors and brightness can be used. With the manual color select option it is possible to increase or decrease the selection based on the size of the color gradient. If the selection is defined and OK is pressed the part of the image is selected and can be adjusted. There are different methods of selecting which can be used for localized adjustment of the image. In order of effectiveness and flexibility in use:
- Color select
- selects a range of colour – preset colour or brightness of the image. Pre selecting a part of the image will limit the colour range selection in that part.
- Magic wand
- selecting a colour range of parts of the images which are connected by the same colour. Similar selection option as the Color range with only less settings.
- Lasso tool
- manually selecting a part of the image by drawing the contour of the selection.
- Fixed shape selection
- manually selecting a part of an image.
If a part of the image is adjusted but there is no fluid transition between the adjusted and non adjusted part of the image the Select – Feather option can be used. This will create a selection gradient at the borders of the selection.
Photoshop has the option of filtering an image. This means that the appearance of the image can altered by a filter. A filter can change the image in, for example, a sketch or an oil painting. This option is very useful to have control over the interpretation of the digital image. The content of a filtered sketch image will be differently interpreted than a realistic digital image of a building. With a wide range of filtering options available the applications are numerous.
The filters can be accessed by the pull down menu . If the option is activated a range of filtering options appear. The top part contains various tools. The bottom part of the menu contains the filters. The best thing to do if you want to explore the different filters is to use the Filter Gallery. It gives you easy access to all the filtering options and gives previews of the effect of the filtering.
Adjusting and repairing images
Sometimes there are objects in your picture that you don't want there. For instance, in the picture below, the little fence in front of the water is not very nice. We also don't want the little pathway in the grass there.
It is recommended to use layers. This is convenient because we are going to place other elements over the undesired parts, so if you work in layers you can always easily delete the pasted part if something goes wrong, and if you work in layers it's easier to edit the new part.
Unlike Maya and Autocad, Photoshop shows the objects in the layers on top of each other in the order shown in the layer box.
In the layer box you see all the layers in your file. When you are using a jpg image there is standard only the background layer. You can add a layer by going to layer > new > layer or by clicking on the new layer icon in the bottom of the layer box:
By double-clicking on the text 'layer..' in your layer box, you can change the name of the layer.
To change the order of your layers you can drag them with your mouse to the desired place.
You can draw in a layer if the layer is current. The current layer is shown in blue in the layer box.
By clicking on the eye-icon next to the layer name you can turn on and off the visibility of the layer.
Copying and pasting part of the picture
A method to get the pathway out of the picture is copying a part of the grass and past it over the pathway. To do this, select a part of the grass that can fit over a part of the path with one of the selection tools and copy it by going to edit > copy:
Now create a new layer, make sure it is above the picture layer, give it a convenient name and paste the part of grass in it by making the layer current and going to edit > paste.
The part of the picture that was selected has now been pasted in the new layer. You can place it over the pathway by using your move tool:
If the edge of the pasted part is clearly visible, you can use the eraser tool from your tool box with a soft brush to make the edges less hard:
The difference is in this case not that dramatic, but it can be useful to make the transition between the pasted part and the picture smoother:
Adjusting the colours like explained in the previous chapter is done per layer, so if the colours of the pasted part don't match the colours of the place where you want to paste it, you can change them easily if you're working in layers.
Clone stamp tool
This tool can be found in the toolbox on the left of your screen and is represented by the icon of a stamp:
With this tool you can directly paste from a chosen spot of the image to another spot in the image by drawing with the brush.
To use the clone stamp tool, make the layer in which you want the pasted part to be in current and select the clone stamp tool. Also for the clone stamp tool it is convenient to have the new part in a different layer than the picture itself, so create a new layer for this. If you are working in a new layer you have to select or check 'sample all layers' at the top of your screen. If you don't, Photoshop will only clone from the current layer. If you now hover above the picture you can see the size of the brush with which you will copy the part of the image, you can change this also at the tool settings at the top of the screen:
Hold down alt on your keyboard when you click on the spot from where you want to start cloning. You will see that if you press alt, your brush will become a target-like icon. After you have clicked a starting point for the place from which to copy, you can release alt and start cloning. Now if you start drawing you will copy from that selected spot onto the spot where you are drawing. The round indicator now indicates where you are drawing, the cross shows what you are copying:
If you turn off the visibility of the other layers you can see what you have cloned:
The image is now like this:
If you want to add information to your picture you can use the same techniques as we described in the previous section. If we would want to add flowers to the grass in the image we can copy them from one picture and paste them into the other. Photoshop will automatically create a new layer for the pasted part:
Now you can erase parts from that layer with your eraser tool to get the flower bed in the shape you want it to be: