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PHOTOGRAPH YOUR AMIGA'S SCREEN TO CREATE PROFESSIONAL SLIDE PRESENTATIONS
By John F. Johnson
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     I created a slide show for a contraception presentation my wife, a
nurse, gave to a group of young soldiers in Germany. To do this, I had to
create text and graphics slides using my Aegis Images software, run the
DPSLIDE show in a darkened room, and photograph the pictures as they
appeared on the screen.
     Some of the things I've learned in the process include the use of
effective AmigaDOS commands, the use of the Aegis Images Change Directory
command, techniques for the creation of consistent text slides, and skills
for taking photographs from monitors.
     Let me share my discoveries with you.
     Some of the helpful AmigaDOS commands include LIST, ED and SORT.
     A. LIST - The use of the LIST command was immediately obvious to
determine what was on my picture disk. Eventually, I became aware of even
better uses for the command. After re-reading Compute's "AmigaDOS Reference
Guide" I came up with this powerful combination of CLI commands:

LIST P #?.PIC TO newfilename QUICK

The commands mean:
LIST        - will spool all data specified
P           - establishes that a pattern follows
#?.PIC      - search pattern looking for a match to anything with
              ".PIC" in it
TO          - specifies where spooled data goes
newfilename - whatever you wish to name the new file
QUICK       - strips all data but the disk filenames
     This means that only Aegis Images picture filenames (suffixed with the
extension ".PIC") are loaded to a specified file (newfilename) and they are
stripped of all extraneous file data, such as dates, times and protection
information.

     B. ED - Now all the picture-file filenames necessary to run the slide
show exist in one file. Next, use AmigaDOS's editor, ED, to modify the
file. In CLI give the command "ED filename". Then make line-by-line
deletions of unneeded filenames. The line deletion command in ED is
"CTRL-B", i.e., a simultaneous press of the CTRL and letter "B" keys. After
the deletion sweep is completed, the slide show instructions are added.
     First, enter the extended command mode by hitting the escape (ESC) key.
An asterisk prompt "*" is returned at the bottom left corner of the screen.
Then, enter the following ED commands:

ESC T;RP E/.PIC/.PIC,2,0,0,1/

Here's what it means:
T   - returns the cursor to the top of file.
;   - separates commands.
RP  - repeats the command that follows until an error is found.
E   - command to exchange string-for-string.
/  - delimits the searched-for and replaced-by string

     Press the RETURN key to complete the transaction. The first string,
".PIC", is replaced with the second string, ".PIC,2,0,0,1", which is the
series of commands I use for taking photos from the screen. Other codes are
possible, but this works best for me with photography.

C. SORT - Next arrange the order that the slides are shown. For photo slide
shows this isn't critical, because the slides may be manually sorted after
they are returned from processing. However, if the slide show is to be
videotaped, arrange the order within the DPSLIDE control file. Instead of
using ED's horribly tedious Block Transfer commands, let the SORT command
do the hard work.
     My picture filenames are mnemonic, i.e., PILLADV.PIC is a text slide
about the advantages of birth control pills. To sort the filenames within
the control file, add a prefix letter to each file member. For example, "P"
for the pill, "I" for IUD, etc.
     Get as detailed at this step as is necessary. To further qualify the
sorting sequence, specify a second alpha or numeric digit. Another
alternative is to do an initial sort to help organize the filenames. To do
this, issue the simple CLI command "SORT filename TO newfilename". The new
file members will be rearranged in main groups that you have specified with
the first character. Adding further prefix qualifiers will further refine
the sort.
     It is important to add the same number of characters to the beginning
of each member name so the original names will be restored after the steps
that follow. Again, enter the extended command mode by hitting the escape
(ESC) key. Next, use the following ED commands to delete the prefixes,
returning the member names to their original state:

T;RP(nDC;N)

T;RP - as explained before
( )  - to enclose a series of commands
n    - number of times to perform following command
DC   - delete character (delete as many as you added)
N    - moves cursor to next line to repeat process

Press the Return key to complete the changes.


AEGIS IMAGES
     Change Directory - When I first used the Images software I kept filling
up the disk with pictures. I had to make a new Images disk by dragging the
software icon over another disk. I couldn't figure out how to get rid of
unwanted files until I learned about the CLI DELETE command. I even wrote
to Aegis suggesting that a deletion routine be added to the product. They
informed me the suggestion has been passed on to their programmers. If
nothing else, their documentation should at least inform their users how to
use the CLI DELETE command. Since discovering the command, I've cleaned up a
lot of junk.
     That method required quitting Images, entering CLI and deleting the 
unwanted files. A more productive method to keep Images' disk space free 
is to:
     -- Have a formatted disk in your external disk drive (how can anyone
work without two drives?)
     -- Pull down the Images Project Menu by moving the cursor to the Title
Bar while holding down the right button on the mouse.
     -- Specify Change Directory.
     -- Within the open window spell out "DF1:".
     -- Press the RETURN key.
     Thereafter, the disk accessed will be on the external device and any
saves made will go there. This saves time in another way, too. If you copy
DPSLIDE to the same disk, you can use it as your PIX disk. Then simply ED
a file as discussed above to run your slide show. If you have files saved
on the Images disk that you wish to have on the PIX disk, change directory
to DF0:, open the file, change directory to DF1: and save as whatever name
you wish. Images automatically adds the ".PIC" suffix.

CREATING TEXT GRAPHICS
     To quote "Inside Aegis Images", the book that comes with the software:
"To create text:
     * Hold the Menu button with the cursor on the Shape selection and
       drag the cursor down until it highlights the word Text. Release
       the Button.
     * Place the cursor on the screen where you want to start printing text
       and click the Selection button.
     * Use the keyboard to type in the text on the screen. The text will
       be displayed in the current color. The backspace key works if you
       make a mistake and want to back up."

     Sounds good so far, but there are some tips and bugs to know about.
When it comes to placing "the cursor on the screen where you want to start
printing. . . "? Well, yes that's what you do, but if you want precise or
consistent placement , you need to know things that aren't covered in the
book. For example, the text cursor is an odd shaped "F", but you don't see
that until after you have used your other cursor (the current brush shape)
to place it. What I recommend is selecting the cross hairs brush from the
Brush Options menu, because the results are more predictable. The only way I
can describe the alignment is to think of the cross hairs as an intersection
made up of four corners. The F-shaped text cursor describes a path you are
going to walk. Approach the intersection from the south walking on the
eastern sidewalk. When you cross the street, stop halfway across, turn
right (east) and walk down the middle of the street. If you put a map of
that route over the one of the intersection, you would have a rough idea of
the correlation of the cross hairs and text cursor. It's tough to describe,
but with practice you will understand what I mean. With Grabbit software, I
could snap a picture of the screen illustrating my point, but I do not own
that program.
     There are a number of reasons to want that kind of precision. One use
is to create a font with dimension to it:
     -- On a dark background type a white heading in caps.
     -- Use the Return key to scroll the text cursor off the bottom of the
screen and back to the beginning of the heading line.
     -- Space to the first letter of the heading. The text cursor should be
wrapped around the letter, like a wrench around a nut.
     -- Place the cross hairs over the text cursor so the horizontal gap
sandwiches the top crossbar of the text cursor. The lower right-facing angle
of the cross hairs should be butted up to the left side of the text cursor.
     -- Now slide the mouse slightly to the left until you first see motion.
     -- Click on the left mouse button once and the text cursor should move
slightly left.
     -- Change the color of your font to black.
     -- Retype the heading in a pseudo 3-D font.

     Another use for precise text cursor placement is to correct errors in
typing. Typing text in Images is a slow, methodical process. The QWERTY
keyboard was developed to slow down the typists on the earliest typewriters,
but that's still not slow enough for the text software in Images. Typing
errors will occur. Your fingers are just too fast for the program. As the
quote from "Inside Aegis Images" says, "The backspace key works if you make
a mistake and want to back up. . . ." to erase errors, but there are some
catches.
     If you have been working on another text screen and cleared the screen,
some vestiges of that screen will show up occasionally when you backspace to
erase errors on your new screen.
     One way to fix the junk that shows up backspacing is to paint it out:
     -- Select the large Block brush from the Brushes menu.
     -- Select the same current color or pattern as your text background.
     -- Choose either Freehand or Line from the Shapes Option menu.
     -- Wipe the contaminated area clean.
     This method seems best for garbage discovered during backspace
deletions.
     If you have manually modified the space between lines for better
placement, kerning or other reasons, you may need to return to a line to
make corrections.
     1. Make the current color identical to the background's.
     2. Use the cross hairs alignment method to place the text cursor at
the first letter of the line being corrected.
     3. Type the letter and case identical to the first letter in the line.
     4. If it disappears the alignment is correct. Skip to step 6.
     5. If not, backspace to delete the letter and repeat steps 2 - 4
until successful.
     6. Backspace to delete the test letter.
     7. Change the current color to the desired color.
     8. Use the spacebar to space to the end of the line (spacing forward
does not affect existing text).
     9. Backspace to delete the offensive letters.
     10. Type the corrections.

MAINTAINING CONSISTENCY IN YOUR SLIDES
     Here are two simple methods to preserve slide consistency.
     -- Use the same background color or pattern for those slides covering
related subjects.
     -- Keep the placement of text lines fairly regular throughout the slide
show by aligning the text cursor at the northwest corner of the screen using
the cross hairs. Then space down and over to the desired starting point.

SLIDE PHOTOGRAPHY FROM THE SCREEN
     I've been creating slide presentations for many years. These are some
of the things I've learned:
     1. Use a macro lens to permit close focusing.
     2. Take the photos in a darkened room to prevent glare from the screen.
     3. Use a medium speed film, ASA 100 or 200, to give a fast enough film
speed without creating excessive graininess.
     4. To avoid a diagonal slash and uneven exposures, shoot the screen at
1/15th of a second or slower to capture the full raster scan on the
terminal. The slower exposure also permits a smaller aperture opening,
providing greater depth of field, which means your focusing has some leeway
for error.
     5. Bracket camera exposures to ensure that the slides have the correct
density. Of the light that falls on a scene, on the average 18% is
reflected. Light meters are calibrated to take an "average" picture based
on a gray card which reflects 18% of the available light. Take an exposure
reading from an 18% gray card and shoot the photo using the camera's
recommendations, and the photo looks 18% gray. Take a reading from a white
wall and shoot the photo using the recommended reading; the photo looks
gray. The same thing happens if a photo is made of a black wall using the
recommended exposure - a gray wall. That's why bracketing is recommended,
to get white walls when a white wall is photographed, and black walls when
black walls are shot.
     If only bracketing would give me white walls where my daughter's
fingerprints exist.
     To bracket shots, use the exposure that the camera's meter says is
correct, and then take a photo one stop faster and one stop slower than the
meter indicates. To do that, open and close the aperture one number (f-stop)
higher and lower than the suggested exposure. If the speed is set at 1/15th
of a second and the meter indicates that an aperture of f/8 is correct,
expose the film three times - once at f/5.6, once at f/8 and once at f/11.
     If you have an automatic camera and cannot adjust your metering, you
can still fool the exposure meter by changing the ASA setting for the film.
Merely double or halve the film's normal ASA to accomplish the bracketing.
An example - if you have film with an ASA of 100, shoot the slide show three
times - once at ASA 50, once at ASA 100 and once at ASA 200. After the first
few experiences, the proper exposure will be obvious and you may just shoot
the screen with the exposure which works for you.
     6. Use a tripod and a cable release to avoid camera shake.
     7. Frame the shot through the viewfinder keeping the edges of the
viewfinder parallel with the edges of the terminal to avoid a keystone
effect.
     8. Do not use Polaroid Instant Slide Film. The film and monitor screen
both have a grid pattern which combine to create a distracting, rippling
moire pattern. Avoid it if possible. Sometimes, for quick and dirty work, it
will do, but Kodak's Kodachrome and Ektachrome films work better. If time is
a factor, the Ektachrome can be developed at home, though it's an unpleasant
chore. In many cities there are custom labs that cater to professional and
commercial photographers. For a premium price they will expedite development
of film with critical turnaround times.

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