Photoshop Tutorials #1 - Understanding Image Size and Storage

These photoshop tutorials were written by Cressida Goddard. Click here to go to her site
To start these photoshop tutorials, we will define some terms

Image Resolution

The fineness of detail in a digital image.

Image Size and Resolution

If the number of pixels stays the same in an image, then, as the size of the image increases, the resolution (fineness of detail) decreases.

• Images which are intended to stay on screen, need to be a low resolution. Why? Because monitors only have a resolution of 72dpi, a resolution considerably higher isn’t able to be displayed.
• Images which are intended for printing, need to be a high resolution. The printed image and the on-screen image are completely different entities. An image printed at 72dpi will be a low quality image.
  
  

Pixels (image elements)

The individual dots that are used to display an image on a computer monitor. The higher the resolution, the more pixels.

DPI (dots per inch)

A unit that is used to measure the resolution of a printer or imagesetter.
Dpi is sometimes used to describe the input resolution of a scanner, but ppi is the more accurate term.

Flash Tutorials in Video Format - Watch them now at LearnFlash.com  

Storage

RAM (Random Access Memory)

The system memory of a computer that is used for running an application and processing information, and for temporary storage.

Zip Disk

100 Megabytes

Floppy Disk

1.4 Megabytes

CD-ROM

Approx 600 Megabytes

File Size

File size is measured in bytes, kilobytes, megabytes, or gigabytes.
8 bits = 1 byte
1024 bytes = 1 kilobyte
1024 kilobytes = 1 megabyte
1024 megabytes = 1 gigabyte

File Formats used in these photoshop tutorials.

PSD

Photoshop file is the only format in which multiple layers and layer transparency are available. PSD’s are large files.

JPEG

(Joint Photographic Experts Group) A compression method in photoshop that shrinks a file's storage size, but which can also cause image degradation as a result of data loss.

TIFF (Tagged Image File Format)

A common format that is used for saving a bitmapped image, such as a scan. A TIFF image can be colour separated and can contain colour management profiles. Used for magazine, high quality images

BMP

Large file, standard windows format, not compressed

PNG

New format, good for alpha channel masking to Flash

Vector Graphics (lines / circles)

Used in Illustrator, Corel Draw, Autocad

Bitmap Graphics (pixels)

used in Paint programs, Photoshop

[ Photoshop tutorials #2 - scanning ]

The second part of the photoshop tutorials will deal with scanning.

• Make sure the scanner is switched on before the computer is turned on.
• To start these photoshop tutorials, place image or object in the scanner, close the lid.
• In Photoshop select File - Import - Twain_32
• The scanning software will appear outside photoshop. When the preview of the scan comes up;
• Select with the crosshairs the area you want to send to photoshop. This will greatly reduce the file size of the scan during these photoshop tutorials.
• Select the image type ie colour drawing, sharp colour photo, B/W photo.
• Check the size of the image and make adjustments.
• Change the resolution depending on the destination of the final scan
• Send the image to Photoshop

[ photoshop tutorials #3 - Tips for Better Scans ]

The 3rd part of the photoshop tutorials will give further instructions on gaining better quality images.

• Place the image in the scanner making sure it is straight to prevent having to rotate it later.
• Try to use a high quality image to scan where possible
• Scan the size you plan to use to avoid scaling in your page layout applications.
• Check the calibration of your scanner to get the best scan you can so you can do as little adjustment as possible when in photoshop.
• When scanning material that has been printed on both sides, place a black piece of paper behind the page in your scanner. This will prevent the printing on the back from showing in the scan.
• Make sure you think about where the final image is going (ie print, web) before starting the scan. This information is essential for selecting the scan resolution.
• For doing straight reproduction images where faithful colour reproduction is important, your monitor, scanner and printer all need to work together to produce the correct image.
• If your scanner or printer tends to put a wash of colour over the image, notice it and learn to overcome the problem.
  photoshop tutorials example:- scan a photo , don’t do anything to it and then print it , then compare this image to the original photo .
  if there is a yellow tinge to the image for example find a way in photoshop to override the problem.
• Make adjustments like sharpening later in Photoshop.
• Never use Brightness/Contrast in photoshop to adjust photos as it destroys too much information, use Curves or Levels instead for the purposes of these photoshop tutorials.
• File size grows faster than scan resolution. The file size of an image scanned at 200ppi is four times greater than when it is scanned at 100ppi.

[ photoshop tutorials #4 - improve your digital photographs ]

The 4th of the photoshop tutorials will deal with handy hints for getting the best out of your photoshop image processing.

• Think about composition before taking the photo
• Experiment with different settings taking the same photo.
• Don’t place the subject in the centre of the photo.
• Sometimes it is good to fill the frame with the subject and not include any background.
• Sometimes it is good to let the background take over and let the focal point be very small.
• Shoot at the eye level of your subject.
• Compose from different angles.
• For a portrait, think about your subject’s personality and try to capture it.
• Use a tripod, or don’t use a tripod to get a blurry effect.
• Print on good quality photographic paper from a good quality printer if possible. Epson papers are good.
• Print at a high resolution eg 300 dots per inch (dpi).
• Take more pictures than you need.
• If compressing the file in JPEG format, use the optimum compressing setting.
• Look carefully at other people’s photographs and the way they have framed the composition. Be critical, do you think they work as a composition?
• Remember that you don’t have to take photos of breathtaking landscapes or good looking people, sometimes photos of objects, which you would never consider, make beautiful photographs. E.g. a brick wall, the top of someone’s head, a doll, textures.
• Remember Photoshop is very handy for quickly cropping images and correcting mistakes.
• Break all the rules

[ photoshop tutorials #5 - Photoshop Exercise ]

The 5th of the photoshop tutorials gives you exercises to practice and enhance what you have learnt during these photoshop tutorials.

Navigation

• Open Adobe Photoshop using the shortcut on the desktop.
• In the Photoshop screen choose File - New. Accept the default settings and you should get a white document on your screen.
  
• Save your document to the hard drive.
• Have a look at the toolbox on the left-hand side of the screen, experiment with different tools by clicking on them and using your mouse to draw on the document.
• When you have finished experimenting, press F12, this will take you back to the blank document.
• Now choose the paintbrush tool and write your name with the mouse.
• Then experiment with filters from the Filter menu.

[ photoshop tutorials #6 - Zooming ]

• Using the zoom tool is very helpful to making accurate selections and paint work.
• Choose the zoom tool and click on the image to zoom in.
• Choose the zoom tool and press the Alt key while clicking to zoom out.
• Note: Zooming does not change the image size or anything else in the image. It is just a temporary viewing option to help you with selections, painting etc.

[ photoshop tutorials #7 -Selecting an area ]

Marquee tool

• Select the Marquee tool and draw a rectangle around the area to be selected.
• Press Ctrl / D to deselect.

• Open an image in the samples folder, which has one solid colour somewhere within the image.
• Use the Magic Wand tool and click on the area with the solid colour.
• If the whole area is not selected, use the Shift key while clicking with the mouse to select more of the area.
• On the keyboard press Ctrl/D to deselect the area.

• Using the same image select the Lasso tool
• Trace around part of the image
• Notice how difficult and inaccurate it is.
  
• Filling a selection
• After making a selection with the magic wand tool, choose Edit / Fill

• Open an image from the samples folder.
• Select the Crop tool, which is hidden under the marquee tool. Then click and drag around the part of the image you want to keep.
• Then press Enter. The image is cropped.

[ photoshop tutorials #8 - Image Adjusting ]

• Open a file you have already been working on.
• Choose Image-Adjust, and adjust the image with a number of the tools in this menu.
• Then press F12 to revert to the previous image.

• If the brushes palette is not visible, choose Window - Show Brushes.
• Open a blank document, make sure black is the foreground colour.
• Choose the Paintbrush from the toolbox and experiment with different brush sizes.
• Experiment with the eraser, airbrush etc... Notice that their thickness is also controlled by the brushes palette.
• Note: When choosing a tool, if you double-click on it you will usually get an options palette to give you more control over the tool.

[ photoshop tutorials #9 - Text ]

• Open a new document File-New and accept and the default settings.
• Select the Type tool from the toolbox.
• Click anywhere on the document. A dialogue box appears.
• Select font, font size and colour.
• Type in your name

Cloning part of an image

• Choose the Rubber Stamp tool from the toolbox.
• Alt / Click an area that you want to clone. This copies that area of the image.
• Then, without pressing the Alt key, use the mouse over the area you want to clone to.

[ photoshop tutorials #10 - Layers ]

• Open 2 images from the samples folder.
• Select the Move tool, click one image and drag it across to the other image.
• Go to the layers palette on the right hand side of the screen. Notice that you have a Background layer and a Layer 1.
• Click on the Layer 1 and then adjust the opacity slider in the palette to 60%.
• Notice that the background layer is now visible underneath layer 1.
• Make sure Layer 1 is highlighted in the layers palette.
• Choose Layer - Free Transform and reduce the size by clicking and moving the corner handles.
• Then press enter to remove the box.

Info on layers

• In the Layers Palette you can;
• Temporarily hide layers by clicking the eye icons on and off.
• You can click and drag layers up and down to change the order of the layers
• Note. The top layer in the palette is the top layer in the image.
• You can change the opacity of a layer and change the blending mode on a layer.
• You can create a new layer by clicking the new layer icon at the bottom of the palette.

[ photoshop tutorials #11 - Understanding Resolution ]

• Open the two images titled 300dpi and 72dpi.
• Take note of the print size of both images.
• Choose View - Actual pixels for the 300dpi image. This shows the image at 100%. Notice the image is sharp and appears to be huge.
• Then zoom in on the 72dpi image until it is at the same size as the 300dpi image. notice how pixelated the 72dpi image is.

Resolution

• The number of pixels or dots in an image
• A monitor can only show 72dpi, so when an image has a resolution larger than 72dpi.
• The monitor can only display the image by enlarging it to fit in all of the pixels.
• If you were to print both images they would be the same size on the page.
• The only difference being that the 300dpi image would have sharper detail.
• Therefore
• 72dpi is suitable for images which will stay on screen eg web pages, animation, video.
• 300dpi is suitable for printing quality images.

Display and Screen modes

• Open a file
• By pressing the F key repeatedly you see that there are 3 screens to view your work in.
• Then by pressing the Tab key you will temporarily hide the toolbox and the palettes.
• To hide or display the palettes only, press Shift / Tab.

This ends the photoshop tutorials for now.
Stay tuned for further developments on this front !