© 1999, Darryl C. Nicholas, All Rights Reserved
So, let's see--you
shoot with a 35mm camera and occasionally want the lab to make an 8x10
print for you. That's nice. Except whenever the lab does that,
they always cut off the edge of the picture. Or, they make a 7x10"
print and you are left with a lot of white space above and below your
picture. Either way, it isn't exactly what you wanted.
Then, you remember there's something called aspect ratio. It has
something to do with not being able to make an 8x10" print from
a 35mm negative without losing something from the edges.
Well, if you think that's all there is to it, hold on. There's
Over the years we have developed over 60 different, official, sizes
of pictures. It seems that every time a company decides to invent a
new camera, they invent a new frame aspect ratio to go with it.
Now, it's true--some of the cameras and frame sizes have
been retired over the years. But, there are still a lot to contend with.
I'd hate to guess at how many different sizes of negative carriers
have been made over the years, let alone how many I have accumulated
in my darkroom.
Before I go further, I want all of you history and math experts to put
it on "Pause" for a while. I don't need long letters
telling me that I didn't tell the whole story. What I'm
going to reveal here is the short, abridged, version of this subject.
If anyone really wants all the gritty details, you can spend a day in
your local, friendly, library.
Here goes. The Golden Mean is a ratio that is present in the growth
patterns of many things--the spiral formed by a shell or the curve
of a fern, for example. The Golden Mean or Golden Section was derived
by the ancient Greeks. Like "pi," the number 1.618...is
an irrational number. Both the ancient Greeks and the Egyptians used
the Golden Mean in their temples. Artists as diverse as Leonardo da
Vinci and George Seurat used the ratio when constructing their paintings.
These artists and architects discovered that by utilizing the ratio
1.618:1, they could create a feeling of order in their works. Even today,
artists are still using this proportion.
The Golden Mean is also called the Golden Ratio, or Golden Rectangle.
Of course, the Greeks also gave us a lot of our current understanding
of mathematics, which is all a part of this aspect ratio thing. Since
I don't want too many of you nodding off, I'll stick to
discussing how all of this bears on photography.
Here are the most simple of instructions for constructing the Golden
Rectangle--a rectangle whose sides measure 1 and 1.618, or a ratio
of 1.618:1. The Golden Rectangle was so popular that it formed the basis
for much of human history and art. The Golden Rectangle is very close
to what we, today, call a 35mm frame. It is also almost the same ratio
as most credit cards, paperback books, legal tablets, "D"
size drafting paper, high density television screens, and the Classic,
Advanced Photo System (APS), print size of 4x6".
It seems that since we humans have two eyes, we tend to see things in
a rough, rectangular, horizontal, pattern. Which is approximately the
same ratio as the Golden Rectangle. Therefore, whenever we see a picture
with those proportions, it appears to seem natural, or normal. Conversely,
when we see pictures that have different proportions--like square--they
just don't quite seem as pleasing. They don't "fit"
into our mind's eye quite right.
Incidentally, I recently bought a new Kodak DC260 digital camera. I
like this camera. It captures just enough data to allow me to make a
beautiful 8x10" print. Want to guess what its aspect ratio is?
It is almost a perfect match for the classical 35mm ratio--1.50:1,
which is very close to the old, Greek, Golden Rectangle of 1.618:1.
To be specific, the camera captures images that are 1536x1024 pixels.
If you multiply those two numbers times each other, you get 1,572,864.
That is where Kodak gets the 1.6 megapixel figure that they advertise.
Actually, the camera captures 4.5MB of data. If you take the image into
Photoshop or a similar image manipulation program, you can then interpolate
up the real data to about 20MB, which is about what is needed to make
a good quality 8x10" print. When you do that, you are asking the
computer to "look" at every two real pixels of data and
make up about 2-3 new pixels to place between them. Computers can do
a pretty good job of that. As a rule of thumb, I try not to attempt
to interpolate much more than that. If you do, the data just isn't
good enough to be able to support photo-quality printing.
If you have specific questions about aspect ratios or digital imaging,
you can write to me care of Shutterbug, e-mail me at: firstname.lastname@example.org.