home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Amiga Collections: MegaDisc
/
MegaDisc 04 (1988)(MegaDisc Digital Publishing)(AU)[WB].zip
/
MegaDisc 04 (1988)(MegaDisc Digital Publishing)(AU)[WB].adf
/
ARTGALLERY
/
DigiViewHints.Usenet
< prev
next >
Wrap
Text File
|
2007-12-01
|
8KB
|
176 lines
Ed. note: Another Usenet download via Lightning BBS in Perth:
this time a lot of hints for how to use DIGIVIEW to best
advantage. Anyone with more, please send them in.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
HOW TO DIGITIZE A PICTURE... HINTS AND TIPS BY ORAN SANDS
ojsands- Plink
The DigiView hardware and software make up a great product, so good in fact
no imitators have sprung up to challenge them. Perhaps the only Amiga
product that can make that claim. Many examples of the system exists on
Plink and local bbs's some good, some great and some not so good.
What makes for a better picture? What determines quality of the picture?
Well I'll let you in on what I've found out through trial and error and pure
dumb luck.
Start with the best equipment.
The software and hardware are fixed givens so make sure the equipment
you add is as good as you can afford (or borrow). The camera must have
the following attributes:
Interlace - 2:1 not random!
Internal Sync (unless you can feed horizontal and vertical drives to it ...
and if you don't know what those are, then stick with internal sync)
High Resolution - Perhaps the most important spec to check. The higher the
resolution the better the picture. The Amiga's horizontal resolution maxes
out at 704 pixels for the full screen. Using a camera with less than this
is underachieving. The better b&w cameras can easily approach 600 - 800
lines of HORIZONTAL resolution (dont get confused with the scanrate of
525 lines vertically). The extra investment will pay off. Your typical
home color camera has only 200 -250 lines of horizontal resolution. Try
to find a good monochrome camera if at all possible.
ALC - Auotmatic level control The human eye can adjust to light levels with
differences of a billion to one. Your camera should have a ALC of 100,000:1
or so if you're not using extra lighting.
Sensitivity - This will usually be low enough if the camera was built in the
last 5 years. 10 lux (10 footcandles) is usually fine.
Signal to noise ratio - The lower the better. The noise in the signal
becomes more apparent as the light level drops (also in the dark sections
of an otherwise well-lit picture.
Good glass - The lower the f/stop of the lens (a number like f/1.9 , f/2.5,
f/4.5 ) the more light the lens will pass to the camera alleviating the
need for more or brighter lighting. A zoom lens is helpful in framing up
the shot as you like it.
Etc. Use good cable and connections. RG-59 coax is proper spec for video
(75 ohm impedance). Try not to use adaptors if possible. Lights can be of
various types, shadowless types are preferable for shooting many things.
Harsh lighting can edge and shadow however and may be what you need.
Choose good pictures.
Although you may think the picture subject is great the picture itself may
not be suitable for digitizing. I've found some good rules of thumb for
choosing them. Stay away from pictures with soft focus, smoky
looking-thru-gauze type pictures ala Penthouse (did I hear a groan?) When
you digitize a picture you effectively reduce its resolution from 3000
lines to 704 (at best). In short, you're ruining the picture!
Starting with a picture with no actual detail doesn't bode well for the
final product. Choose pictures with clear, sharp detail. The subtle
shading of colors in some pics can make life difficult for the software.
Other than HAMs you've only got 32 colors at most to play with. The softare
will allocate the colors the best it can. Don't ask it to work to hard. A
good example is a picture with flesh tones. These colors are perhaps some
of the worst to try to emulate.
A great deal of complex coloration exists in flesh. It can really drive the
program nuts. Pictures with a limited range of colors are good to use. If
your pictures a nude scene you'll need all the colors to portray your
subject. If the background's green or blue (both colors not found in flesh
tones) the software must allocate colors to them to the detriment of your
nude (less colors to go around).
Use small pictures!
I know this sounds strange but try and follow me. A printed picture has an
effective resolution of say.. 3000 lines per square inch. It follows that
the larger the picture the more detail information there is to try to
reproduce. So the smaller the image, the less to reproduce, the less to try
to represent in the digitized image. The software can do its best if its
not being asked to reproduce subtle detail. Almost all the pictures I've
circulated started out no bigger than 4x6 inches.
Use pictures!
Digitizing live pictures can be very difficult. The reason is that
regardless of how close you get to a real object an infinite amount of
detail still exists unlike with printed pictures. There will also be an
almost infinite amount of color shading which will drive the software
crazy.
Summary:
Use clear, sharp pictures
Use small pictures
Limit the amount of colors
The software almost always creates a black and a white. use this to your
advantage. Trim or mask off sections of the picture that contain
non-essential colors or subject. Mask off with either white or black paper.
This will allow the software to use its black and white on the background
and not have to waste other colors to represent the unnecessary sections.
Light at a 45 degree angle or there abouts. Look for reflections on the
picture or the detail of the texture of the paper. The texture of the paper
can cause the software to see subtle differences in the colors and again
wasting colors.
Use enough light. The program will optimize the the monochrome image (the
second pass of the scan , from top to bottom). Once again, don't make them
program work too hard. If you have enough light the software won't diddle
with the brightness and contrast any more than necessary. Even with a
perfect image the program will still do some correction. Look at the
histogram. It shows your signal and the program's version of it. They
should be as similar as possible.
Don't leave the image alone. Use the color controls to adjust the pic.
I find the image always needs a few increases on the brightness control.
Check out the dark areas where you know there are details but you can't see
them. Get familiar with the controls and what they do. Don't adjust several
at a time. You'll get a result and won't know what did what to the
picture. The sharpness control provides edging on details. This can be
great or a nuisance. Make small adjustments at first. Keep increasing a
little at a time.
If the picture has mostly reds but they look weak compared to the other
colors increase just that color. Remember that many of the other colors may
have a red component and will go somewhat reddish however. Play around,
have fun!
Use a image manipulation program such as Butcher, FPIC etc. to further
adjust the picture. Butcher's ability to merge colors can help free up
colors for use as other things. Such as text in a paint program such as
DpPaintII. Using Dpaint II can be a godsend. Use it to paint out those
annoying staple holes (Playboy readers disregard). If the background is a
solid color check it out carefully. You'll find that its probably a mixture
of several similar colors.
Paint out the background so it really is solid. This will reduce the image
file size dramatically!! If you're up- or down-loading it helps. Many of
my pictures have had backgrounds removed, objects moved, entire sections
repainted to remove random pixelization. Be creative.
Don't allow youself to beat a dead horse. All my pictures are good because
I've thrown away twice as many that never quite made it to their potential.
I've got a Countach picture I've been working on for two months and it's
still not quite right! Keep at it and have fun. Digitizing can produce some
awesome images and it keeps us off the streets. I'd rather be an artist
like Sachs but I'll settle for good images however they come about!
^^^^^^^^^^^^^^^^^^END OF DIGIVIEWHINTS^^^^^^^^^^^^^^^^^^^^^^^^^^