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NAF Graphic Design

Lesson 6Basic Photo Corrections

Student Resources

Resource Description

Student Resource 6.1 Reference Sheet: Photo Correction Tools

Student Resource 6.2 Photo Correction Chart: Which Tool?

Student Resource 6.3 Interactive Reading: Improving Color and Sharpness in Photos

Student Resource 6.4 Reference Sheet: File Formats

Student Resource 6.5 Assignment Sheet: Photo Planning and Corrections

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NAF Graphic DesignLesson 6 Basic Photo Corrections

Student Resource 6.1

Reference Sheet: Photo Correction ToolsStudent Names:_______________________________________________________ Date:___________

Directions: Fill in this reference sheet according to your teacher’s instructions.

Healing Tools

Tool Name

Description Important Options

Healing Brush

Correct imperfections by painting over and blending them with sampled pixels from another area.

Spot Healing Brush

Remove blemishes by automatically selecting pixels from the area around the retouched area.

Patch For larger corrections, select the area that needs correction and replace it with pixels from another area.

Red Eye Click in the middle of a red eye to remove the red.

Clone Stamp

Select pixels from a sample point and paint them into an area that needs correction.



Toning Tools

Tool Name

Description Important Options

Dodge Paint over shadowed areas to lighten the area, which can bring out the details hidden in the shadows.

Burn Paint over washed-out areas to darken the area.

Sponge Make subtle adjustments to color saturation.

Color Tools

Color Balance

Change the overall mixture of colors. (For example, if the shadows look too green, subtract some green and add some red to balance.)

Levels and Curves

Correct tonal ranges and color balance to fix poor exposure.



Hue/ Saturation

Adjust the hue (color), saturation (intensity), or lightness of a color component in an image.

Sharpening Tools

Unsharp Mask filter

Focus images by increasing the contrast of adjacent pixels, adding emphasis to the edges of objects.




Photo Correction Chart: Which Tool?Student Names:_______________________________________________________ Date:___________

Directions: Look at the before and after version of each photo on your computer, and then write down the corrections that you can detect in each “after” photo. Finally, write down your guess as to which tools were used to make the corrections.

Photo What Corrections Do You See? Which Tools?

Your guess:

Tools actually used:

Your guess:


Your guess:


Your guess:





Interactive Reading: Improving Color and Sharpness in Photos

Student Name:_______________________________________________________ Date:___________

Directions: Read about each Photoshop tool and then try out the tool according to the instructions provided. Be sure to record your experience as directed in the “Your Notes” area.

Color issues in photos can result from incorrect exposure, lighting issues, color casts, and other problems. Photoshop contains a variety of tools for correcting these color issues. Before you make color adjustments, remove any flaws such as blemishes and scratches from photos.

The Histogram PanelThe Histogram panel is a way to keep tabs on your image as you are adjusting the color and tones. Keep the Histogram panel open while you are working on color and tone adjustments to check that your image maintains full tonality. You can open the Histogram panel from Window > Histogram.

A histogram shows how pixels in an image are distributed by graphing the number of pixels at each color intensity level. It shows if there is enough detail in the shadows, midtones, and highlights. The left part shows the detail in the shadows, the middle shows the detail in the midtones, and the right part shows the detail in the highlights. An image with full tonal range has some pixels in all areas.

Look at the histogram at the upper left in each of the images above. The left image shows an overexposed photo. Note that the histogram shows no pixels in the shadows area on the left. The middle image shows a properly exposed photo with full tonality. Note that the pixels are spread across the histogram. The bottom image shows an underexposed photo, with no pixels in the midtones or highlights.

Try Out the Histogram PanelOpen a photo of your choice in Photoshop and then open the Histogram panel.

Your Notes:What does the histogram tell you about the tonality of your photo?



The Adjustments Panel

Most tools for making color and tonal adjustments are located on the Adjustments panel. When you click one of the tool icons on the Adjustments panel, Photoshop opens the dialog box for the tool and automatically creates an adjustment layer on your image. Creating this adjustment layer gives you more flexibility and means that you do not lose image information when you make adjustments. Before beginning any photo manipulation, it is a good idea to create a copy layer of the background so that you have the untouched original as a reference.

Levels Tool

You can select the Levels tool from the Adjustments panel. Use the Levels tool to correct the tonal range and color balance of an image. Drag the black triangle marker to introduce contrast in the image. Drag the white triangle to set the image’s white point and reassign where white should begin in the image.

You can use the middle input levels (gray) slider to change the intensity of the midtones. This lets you expose the image better. Drag the midtone slider to the left to add light; drag it to the right to subtract light. The Levels histogram is a visual guide for adjusting the image tones.

Tip: To give your image added crispness in the shadow areas, convert your file to CMYK (Image > Mode > CMYK Color) before working with the Levels tool.



Curves Tool

The Curves tool is also used to adjust the tonal range or color, but it gives you more control than the Levels tool. The Curves tool has up to 16 control points, whereas Levels has only three. In the Curves dialog box, the tonal range is represented as a straight diagonal baseline with highlights in the top-right corner and shadows in the lower-left corner. When you first open the Curves dialog box, there are two points: one for white and one for black.

You can adjust the tonality and color of an image by changing the shape of the curve in the Curves adjustment. Moving the curve upward or downward lightens or darkens the image. The steeper sections of the curve represent areas of higher contrast; flatter sections represent areas of lower contrast. The Curves dialog box also has a pointer tool in the upper right that you can use to click the area of the image that you want to adjust. You can drag the pointer up or down to lighten or darken the values for all similar tones in the photo.

Color Balance Tool

You can select the Color Balance tool from the Adjustments panel. This tool changes the overall mixture of colors in an image. You can remove unwanted color casts or correct oversaturated or undersaturated colors. For example, if the shadows look too green, you can subtract some green and add some red to balance the image.

Drag a slider toward a color that you want to increase in the image; drag a slider away from a color that you want to decrease in the image.



Hue/Saturation

The Hue/Saturation tool lets you adjust the hue (color), saturation (intensity), and lightness (which adds white or black) of a specific range of colors in an image. In addition, you can simultaneously adjust all the colors in an image.

You can also use the Hue/Saturation dialog box to tint an image by checking the Colorize box.

Try Out the Adjustments Panel ToolsOpen a photo of your choice in Photoshop and then open the Adjustments panel. Try out the Color Balance, Levels, Curves, and Hue/Saturation tools.

Your Notes:Which tools were you able to use to improve your photo? What kinds of improvements did you make?



Sharpening Edges

As one of the final steps in correcting a photo, you can use the Unsharp Mask filter to sharpen the clarity of edges in the photo. The Unsharp Mask filter sharpens an image by increasing contrast along edges. It locates pixels that differ in value from surrounding pixels by the threshold you specify. For example, a threshold of 4 affects all pixels that have tonal values that differ by a value of 4 or more, on a scale of 0 to 255. The filter increases the contrast of neighboring pixels by the amount (percentage) you specify. So neighboring pixels that are lighter get even lighter and neighboring pixels that are darker get even darker. With the Radius slider, you specify the radius of the region to which each pixel is compared. The larger the radius, the greater the edge effects. Too much sharpening may result in a halo effect around the edges.

Try Out the Unsharp Mask FilterOpen a photo of your choice in Photoshop and then open the Unsharp Mask filter.

Your Notes:What values did you use to improve the sharpness of your photo?

Amount:

Radius:

Threshold:




Reference Sheet: File FormatsStudent Name:_______________________________________________________ Date:___________

Directions: Read the file format descriptions in the chart below and then choose the file format that matches the description. Write the file format name in the left column of the chart.

File Format Description

This image file format is supported on the web and recognized by most graphic editing programs. It uses lossy compression, which eliminates some color detail but can shrink a file to about 5% of its original size. The information that is discarded in the compression is information that the human eye cannot detect. This format supports 16 million colors. It’s best suited for photographs and complex graphics.

This image file format is supported on the web. It uses a lossless compression technique and supports only 256 colors. Good for images with only a few distinct colors, such as line drawings, black-and-white images, and small text that is only a few pixels high. It supports transparency, where the background color can be set to transparent in order to let the color on the underlying web page show through. This format can support animation.

This image file format is supported on the web but is not supported by all browsers. It uses lossless compression but can have millions of colors. An image in this file format can be 5% to 25% more compressed than a GIF file of the same image. It supports transparency and allows control of the degree of transparency, known as opacity.

This is one of the most widely supported file formats on both Macs and PCs for image-manipulation and page layout applications. In desktop publishing, it is the standard format for importing images into documents. It doesn’t use compression, so file sizes are large.

This is a full-color format commonly used for editing raster graphics in Windows. It doesn’t use compression, so file sizes are large.

This is the native file format for all Photoshop software. It supports layers and masks. It doesn’t use compression, so file sizes are large.

JPEG (Joint Photographic Experts Group)



PNG (Portable Network Graphics)

BMP (Bitmap)

PSD (Photoshop Document)

GIF (Graphic Interchange Format)

TIFF (Tagged Image File Format)




Assignment Sheet: Photo Planning and CorrectionsStudent Name:_______________________________________________________ Date:___________

Directions: In this assignment, you will make photo corrections to two photos. Before you start working on the photos, you need to plan out what corrections are needed and think about what tools you will use to make the corrections. Be sure to read through the assessment criteria before you start work so that you understand how your work will be assessed.

RequirementsYou must demonstrate your ability to make photo corrections by making four different types of corrections:

Healing

Toning

Color adjustment

Sharpening

When you select two photos to improve from the Photo_Corrections folder, make sure that you will have occasion to demonstrate all four types of corrections with just two photos.

Planning Your Work1. Look at the images in the Photo_Corrections folder. (Your teacher will give you access to this

folder.) Select the two images you want to improve, and write the names of the images in the left column of the planning chart on the following page of this resource.

2. Study each of the photos you chose and, by working through the following questions, think about how you could improve it. Write down your notes in the “Corrections I Want to Make” column for each photo.

o Are there blemishes of any type that need to be healed?

o Are there objects that should be removed?

o Are there shadows that need lightening?

o Are there washed-out areas that need darkening?

o Are there edges that need to be sharper?

o Are there areas that need to be desaturated?

o Are there areas that need brightening?

o Are there colors that need correction?

o Are there other types of corrections that would improve the photo?

3. In the third column, write down which tool you think would work best for each correction. You may decide to change tools as you are working, but write down the tool that you think would be best to start the correction with.



Photo Name Corrections I Want to Make Tools I Will Use

Making Your Photo CorrectionsIn Photoshop, open the photos that you are going to improve, and make all of your corrections. When you are satisfied with your photo, select File > Save As to save the photo, and append your own name to the file name. Submit this new file, along with your planning chart, to your teacher for assessment.

Make sure your work meets or exceeds the following assessment criteria: Photo corrections show evidence of careful work to get the desired effects listed in your planning

chart.

Healing tools are used effectively to replace unwanted pixels with adjacent pixels, creating a natural look in all areas that are “healed.” All healing work is precise and accurate.

Toning tools are used effectively to lighten shadows, brighten washed-out areas, or desaturate. All toning work is precise and accurate.

Sharpening tools are used effectively to sharpen the edges of items in the photos.

The Hue/Saturation, Color Balance, Levels, and Curves tools are used to effectively adjust color and/or tone.


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