Basic Image File Preparation using Adobe Photoshop 6
copyright
1997, Marvin Bartel, Photography Instructor, Goshen
College file/photPrep.html Further
editing (marked) by Paul M. Reimer, 1998, and Merrill Krabill, 2002.
Located in UN001, there are flatbed scanners and
a slide/film scanner with which to convert any image to a computer file in Photoshop.
See the Scanning Instructions sheet or an assistant if you need
help scanning. For digital cameras, follow the camera's downloading instructions.
WARNING. Copyright law prohibits the publication of images without permission.
Posting web pages and photocopying are forms of publishing. An image does not
need to display ã
in order to have legal protection. When you create an original image, whether
with a camera or otherwise, it has U.S. copyright protection.
- Save it. After scanning, Save the file using the File>Save
command from the top menubar in Photoshop. If you downloaded from a digital
camera, your images will already be saved files.
- Where to save. The first time a file is saved, you get a dialog
box asking where you want to save it. Image files can be temporarily saved
in a folder you make on the computer desktop (the Mac screen is called
the desktop). Diskettes are too slow and may be too small for image files.
Save it temporarily on the Mac desktop so it responds faster while you
work. If you are more comfortable not using a Mac, Adobe Photoshop is
also on the PCs on campus.
- File size. Large high-resolution image files can respond very
slowly in Photoshop. If this is a problem, you may want to scan at a lower
resolution next time. In some cases low resolution just isn't good enough.
See B-5 for more information about file sizes and to make smaller files
after they are scanned.
- Where to save when done working. Images that you want to keep
should be saved in your own drive, on a Zip disk, or on 3.5-inch diskettes,
[or directly to your webserver folder--see the GCWeb
publishers' manual]. Don't leave any personal files on an individual
computer unless it is your own computer.
- Enhance and Correct It. Use Adobe Photoshop to check and make corrections
and enhancements. Here are several easy routines to help make an effective
photograph.
- Use Full Range of Tone. Go to the top menubar. Use Image>Adjust>Levels
to take out any unused latitude. If the histogram shows a flat area at
either end, use the sliders to eliminate the flat area. Almost every image
will be improved by this simple adjustment. Experiment with the center
slider, but most images do not need this adjustment. Select OK
when finished.
- Color Correction. Often digital photos have a slightly magenta
cast. Others have the wrong color balance because of the light during
photographing. Correct color balance by using the Image>Adjust >Variations.
By experimentation the color can be made to look more natural. If we print
out the image on a color printer, we generally find that the printer produces
a different color balance than the monitor does. Artists who understand
color theory can generally get a good print after two or three printouts.
Some monitors can be "tuned" to match the printer, making it easier to
use Variations.
- Crop. Cropping should be done before finalizing the image size.
Crop images to eliminate uninteresting, and/or distracting elements. The
crop tool allows you to draw a rectangle on your image. It has handles
on the corners and the sides which allow you to adjust the size of it.
When you get it positioned where you want it you double-click within the
area that will remain.
- File Size.
[Paul suggests to web graphic designers that they do all resizing directly
in units of pixels].
- Use Ruler. If you don't see a ruler at the top and left of
the image, press Ctrl +R. Use the ruler to help you visualize
the size.
- Image>Image Size from the top menubar can be used
to change the image height and width.
- The Image>Image Size dialog box also gives control of the
file size by stipulating the resolution after we have stipulated the
height or width of the image. Web page images can be set to a resolution
of 72 after they are scaled to size. Lower than this will produce noticeable
deterioration of quality. More than 72 probably won't make them look
better. Images intended for printing will benefit from a resolution
slightly better than the maximum resolution of the printer used.
- Remove Blemishes. If your image has a distracting detail or blemish,
take it out with the any one of several of the tools on the vertical tool
bar. Zoom in on the area first using the magnifying glass from
the vertical tool bar. Your cursor changes to a circle with a + sign.
Click repeatedly to enlarge a detail. It shrinks the image again if you
hold down the Option key on a Mac while clicking (use the Alt key on a
PC).
- The rubber stamp tool (cloning tool) is a convenient favorite
for removing blemishes. It can replace a blemished portion or a distracting
part of a photo with a color and texture from any place else on this
photo or even from another photo open near by on the monitor.
- First you press the rubber stamp button.
- Then position your mouse where you find a color, tone, and texture
you want to copy.
- Hold down the Option key (Alt key on a PC) and click once.
- Move the stamp to the blemish and click on it.
- Repeated use can cover a large blemish.
- Adjusting the size of tools. If the stamp is covering an area
too small or too large, the effective size is adjusted by selecting
a different brush size. Brush size is one of the options for the rubber
stamp tool that is at the top of the screen.
- Sharpening.When you are done with adjusting the photo there is one
last step that will enhance it alittle further. Go to Filters>Sharpen>Unsharp
mask. Have your setttings at Amount=100%, Radius=1.5, Threshold=10. This
will help define the features of the photo.
Note--By now you realize there are a multitude of additional
Photoshop commands. Experiment and use the Help files to improve and manipulate.
You can undo the last change you made with Command>Z(the Command key is the
one with the apple). The History palette will let you undo recent changes you
have made or go back to the last time the file was saved.
- Saving when you are done.
When you have all of the adjustments that you want made choose File>Save
for Web. In the dialogue box that appears there is a row of tabs at the
top left corner, choose the 4-Up. The upper-left window is the original
image. The other three can be given different settings and compared to see which
is the best compromise between image quality and download time. The options
from here on are beyond explaining in much detail for the time we will spend
now. An oversimplified set of directions for an image coming from a typical
photograph would be:
- Click inside of one of the windows.
- Set the file format (the scheme for compressing the image) to JPEG.
- Set the quality at high.
- Repeat steps 1-3 for the remaining windows with quality settings of medium
and low.
- Decide which is the smallest file that still maintains adequate image
quality and click in that window.
- Click Save.
- In the dialogue box give the JPEG file a name and save it into your desktop
folder. You will usually want Images only (not an HTML page with the image
on it).
What you have done is to save a copy of the Photoshop file you have open
with the chosen format and settings. Your original Photoshop image has not
been changed or saved since you started the Save for Web process. When you
close it the prompt will pop up asking you if you want to save changes to
the file. Your choice there affects the Photoshop file, but has no effect
on the xxxx.jpg file you generated.
- Moving finished files to your network folders. When you are done,
drag the files (Photoshop and JPEGs) from the desktop folder into folders
on your M and/or W drives. At night files left on the desktop are erased,
so don't leave information there you want to save.
- Log off so nobody has access to your M drive and W drive folders.
photPrep.html -- by Marvin Bartel/ Gwen Miller, 9-1997 ã