Olympus-OM
[Top] [All Lists]

[OM] Re: One for S:t Adams -- a step by step

Subject: [OM] Re: One for S:t Adams -- a step by step
From: AG Schnozz <agschnozz@xxxxxxxxx>
Date: Wed, 17 Aug 2005 07:46:15 -0700 (PDT)
I think the noisiness in the image was mostly artifacts in
processing for the web image... resizing, usm, jpeg...

This does bring up a rather important discussion about
converting digital files to monochrome.  This is something that
is as much an art form as it is a science.  I definitely do not
profess to have arrived yet, but I continue to attack it like a
viscious (or is that viscous) dog.

I've gotten my best results from in-camera RAW files. Primarily
because of JPEG artifacts and the ability to keep the bulk of
the tonal editing in 48-bit/16-bit mode. JPEG's 8-bit mode
causes you to lose the ability to radically change brightness
levels.

1. Think film.  Make your entire process mimick the film realm
as much as possible.  What works in the analog world does work
in the digital world.

2. Think flat.  Keep the contrast of the image as low as
possible when working in color.  You'll top and tail the curves
much later.  Don't screw things up yet.  If you make the image
too contrasty during capture or when in color, you'll never
recover the subtlety later.  Use Polorizers if you want, but
otherwise don't do any color filtering when photographing or
scanning.

3. Think color response characteristics of film.  Study the
response (spectral sensitivity) curves of your favorite film. 
(published in the product info PDFs from the manufacturers) For
example, take a look at the curves for most B&W films and you
see a marked dip in response to the color green. (around 500nm).
 Lock in the WB to "sunlight", and decrease the green channel
brightness by 20% or so. The following link helps guide you
through the different colors: 

http://eosweb.larc.nasa.gov/EDDOCS/Wavelengths_for_Colors.html

4. Think color filters.  Look at the scene and ask yourself what
color filter, if any, you would have placed on the lens when
taking the picture.  Red, orange, yellow and green are the
standard ones we've used for a hundred years with film.  In the
digital editor, you have cyan, blue and magenta at your disposal
too.  As a general rule, lean towards using a color filter that
crosses the RGB array.  For example, red will result in a
noisier image than orange, but will have almost the same
response.  Cyan and green will be similar, but cyan will tend to
be a little cleaner.  If noise is not an issue, feel free to use
red, green and blue.  However, read the next note carefully.

4a. Red isn't red.  A red lens filter will not give the same
response as a red filter applied during color-monochrome
conversion.  The red filter on the lens isn't 100% effective,
whereas the red filter in the digital editor is.  To counteract
this, take the color balance of the entire image and skew it
slightly towards the red side. And I mean slightly.  It should
have a hint of red hue everywhere. What this does is reduce the
total effect of the red digital filter and keeps the shadows
from blocking up. This is true for all of the colors.  Whatever
color filter you use, give the image a slight hint of that prior
to conversion.  Overly contrasty and obviously digital images
result if you are not careful at this stage.

4b. Convert to monochrome. Most editors now have the convert to
monochrome function which allows you to select the color filter.
 Convert to a 16-bit tiff.

5. Open up the levels dialog box and "top and tail" the
histogram by moving the black and white points to the outer
edges of the "hills".  Adjust the mid-point (gamma) to get the
mids where you want them.  This is quick, simple and gets you
90% of the way there.  Or, if you are a wiz, use the curves
dialog box to accomplish the same thing.  With the curves dialog
box, you can also push up the high levels a little, pull down
the low levels and mimick a toe and shoulder.

6. When you are happy with the overall tonal curves, finish up
with localized dodging and burning.  Don't get too crazy with
Ansel Adams' edge burn.  You can't be subtle enough for it to
really work and overdone is worse than not doing it at all.

7. Sharpen.  If the image is too grainy/noisy, you can apply a
noise-removal algorithm, but that's another subject for another
day.  We'll talk grain emulation later.

8. Save as 16-bit tiff to preserve your hard work.

9. Scale to desired size.  If there is a pattern in the scene,
you may need to multi-step the scaling process using odd amounts
of resizing to get there.  For example, instead of reducing an
image to 25% in one step, you can reduce by 31%, 22%, etc., to
get to your final size.  Sharpen occasionally. This will keep
aliasing artifacts to a minimum.  Especially grain/noise
artifacts that bloom when scaled.

10. Sharpen.

11. Convert to 8-bit BW or 24-bit RGB.  Save as JPEG for web.

12. Enjoy.

The key here is trying to duplicate the film process as much as
possible to achieve a film-like image.  Digital monochrome is
usually very ugly.  Even with the above steps (of which I'm
still developing and adapting), it's difficult to match the
qualities of a decently processed and printed roll of Tri-X.

AG


                
____________________________________________________
Start your day with Yahoo! - make it your home page 
http://www.yahoo.com/r/hs 
 

==============================================
List usage info:     http://www.zuikoholic.com
List nannies:        olympusadmin@xxxxxxxxxx
==============================================

<Prev in Thread] Current Thread [Next in Thread>
Sponsored by Tako
Impressum | Datenschutz