You can find tips on scanning in general here.
You can find tips on scanning for print here.
Basic scanning procedure on a mac
- Turn on the scanner(duh).
- Place your image face down on the scanner.
- Open the image capture application.
- Choose the scanner if it does not start automatically.
- Choose your color depth(24 bit is fine for the web).
- Choose your resolution(see below for web resolution).
- You will need a larger image if your destination is a print document
- Choose your format, either JPEG or TIFF. JPEG is smaller, but compressed, and is usually fine for most purposes. TIFF is large but full quality.
- Start an overview scan if the scanner has not already done it.
- Select what you want to scan in the preview scan.
- Click the scan button.
Tips on scanning for the web
Color: You would usually want to scan at
full color(24 bit).
Resolution: You have 2 main choices as far
as what resolution to scan at for an image going on a web page.
You can scan at a higher resolution than you need. This gives you the flexibility
to resize the image down to the size you need later. You then might need to
sharpen the image afterward using he unsharp mask filter(see
If you know exactly what size you need beforehand, you could scan at the exact
resolution you need to get the image at the size you want for your web page.
To figure out the resolution to scan at for a web page, you can use the following
|your scanning resolution=
||pixel size you want(either height or width)
|original size in inches(either height or width)
|your scanning resolution=
||you want 200 pixels high
|4 is the original height in inches
Your scanning resolution is 50 ppi(pixels per inch)
If you get a moire
pattern from your scan, there are a couple of ways
to repair them, but your better off avoiding them in the first place.
Moire Patterns are not an issue when scanning photos printed traditionaly(not with ink).
To avoid moire patterns:
- Look for a descreening filter in the scanning software.
- Try a different scanning resolution(probably higher).
- Angle the print on the scanner a little.
- Scan at a higher resolution and then downsample.
General Steps to correct and prepare images for screen or print
Some steps can be optional.
- Straightening and cropping
- Use the ruler tool under the eyedrop tool to correct tilt.
- Drag along what should be horizontal or vertical like the horizon or a building.
- Go to image-image rotation- arbitrary to rotate to straight.
- You can also rotate while cropping if you put your cursor near the corner of the crop tool marks.
- Use the crop tool to crop.
- Get this C key on your keyboard to choose the crop tool.
- Hit the enter key to accept the crop, or the escape key to start over.
- Spotting, retouching, dust and scratch removal.
- For spotting, the spot healing brush usually works well.
- Pick a brush at the top that is slightly larger than your spots.
- Click on the spots to remove
- Brightness and contrast/Global tonal correction
- For a quick adjustment of contrast, use a levels adjustment layer
- Click on the adjustment layer button at the bottom of the layers panel and choose levels.
- Drag the black-and-white sliders under the Histogram in towards the center until you get to an area of the histogram where there is some image data.
- Correct colors/saturation/Global color correction
- One way to do a color correction in your image is to use the gray eye dropper tool in a layers adjustment layer and click on something in your image that should be gray.
- Another way would be to go to the channels menu in the levels adjustment layer, and drag the center slider in each channel to adjust the color balance.
- Selective tonal and/or color correction
- This would be for small areas in the image that have a color caste you don't want, like a window.
- You can right click on the layer name and select "Convert to Smart Object" so that you can change sharpening settings repeatedly without damaging your original image layer.
- Sharpen using the unsharp mask or smart sharpen filters under the filter menu. See below for a description of the settings for the filters.
- Suppress noise and artifacts
- This might be necessary if you took a photo using and high ISO setting, or you were trying to fix a JPEG that had been overly impressed.
- Target for print (sharpening, handling out of gamut colors, compressing
tonal range, converting to CMYK.)
Optimize for Web
or USM, is a traditional film compositing technique used to sharpen edges in
an image. The Unsharp Mask filter corrects blurring introduced during photographing,
scanning, resampling, or printing. It is useful for images intended both for
print and online.
The Unsharp Mask filter locates pixels that differ from surrounding pixels
by the threshold you specify and increases the pixels contrast by the
amount you specify. In addition, you specify the radius of the region to which
each pixel is compared.
The effects of the Unsharp Mask filter are far more pronounced on-screen than
in high-resolution output. If your final destination is print, experiment to
determine what dialog box settings work best for your image.
To sharpen an image using the Unsharp Mask filter:
1 Choose Filter > Sharpen > Unsharp Mask.
2 Sharpen the image:
For Amount, drag the slider or enter
a value to determine how much to increase the contrast of pixels. For high-resolution
printed images, an amount between 150% and 200% is recommended.
For Radius, drag the slider or enter
a value to determine the number of pixels surrounding the edge pixels that affects
the sharpening. For high-resolution images, a Radius between 1 and 2 is recommended.
A lower value sharpens only the edge pixels, whereas a higher value sharpens
a wider band of pixels. This effect is much less noticeable in print than on-screen,
because a 2-pixel radius represents a smaller area in a high-resolution printed
For Threshold, drag the slider or
enter a value to determine how different the sharpened pixels must be from the
surrounding area before they are considered edge pixels and sharpened by the
filter. To avoid introducing noise (in images with fleshtones, for example),
experiment with Threshold values between 2 and 20. The default Threshold value
(0) sharpens all pixels in the image.
If applying the Unsharp Mask filter makes already bright colors appear overly
saturated, convert the image to Lab mode and apply the filter to the L channel
only. This technique sharpens the image without affecting the color components.
Sharpen using Smart Sharpen
The Smart Sharpen filter has sharpening controls not available with the Unsharp Mask filter. You can set the sharpening algorithm or control the amount of sharpening that occurs in shadow and highlight areas.
- Zoom the document window to 100% to get an accurate view of the sharpening.
- Choose Filter > Sharpen > Smart Sharpen.
- Set the controls in the Sharpen tabs:
- Sets the amount of sharpening. A higher value increases the contrast between edge pixels, giving the appearance of greater sharpness.
- Determines the number of pixels surrounding the edge pixels affected by the sharpening. The greater the radius value, the wider the edge effects and the more obvious the sharpening.
- Reduce Noise
- (PhotoshopCC only)Reduce unwanted noise while keeping important edges unaffected.
- Sets the sharpening all algorithm used to sharpen the image.
Gaussian Blur is the method used by the Unsharp Mask filter.
Lens Blur detects the edges and detail in an image, and provides finer sharpening of details and reduced sharpening halos.
Motion Blur attempts to reduce the effects of blur due to camera or subject movement. Set the angle control if you choose motion blur.
- Sets the direction of motion for the Motion Blur option of the Remove control.
More Accurate Processes the file more slowly for a more accurate removal of blurring.
- More Accurate (CS6 only) Processes the file slowly for a more accurate removal of blurring.
- Adjust sharpening of dark and light areas using in the Shadow and Highlight tabs. (Click the Advanced button to display the tabs). If the dark or light sharpening halos appear too strong you can reduce them with these controls, which are only available for 8-bits and 16-bits-per-channel images:
- Fade Amount
- Adjusts the amount of sharpening in the highlights or shadows.
- Tonal Width
- Controls the range of tones in the shadows or highlights that are modified. Move the slider to the left or right to decrease or increase the Tonal Width value. Smaller values restrict the adjustments to only the darker regions for shadow correction and only the lighter regions for highlight correction.
- Controls the size of the area around each pixel that is used to determine whether a pixel is in the shadows or highlights. Moving the slider to the left specifies a smaller area, and moving it to the right specifies a larger area.
- Click OK.