TidBITS#809/12-Dec-05
=====================
Charles Maurer returns with a detailed discussion, informed by
perception and painting, of how digital cameras can produce more
naturalistic photos than film cameras. Mark Anbinder looks at the
addition of NBC shows to the iTunes Music Store, Glenn Fleishman
passes on news of new Wi-Fi driver options for Tiger users, and
we examine updates to Firefox, Firefox's Flashblock extension,
[EMAIL PROTECTED], the Prograph programming language, and "Take Control
of Mac OS X Backups."
Topics:
MailBITS/12-Dec-05
DealBITS Drawing: Classic Solitaire
Prograph Spelled Backwards Is Marten
NBC Universal Brings More TV to iTunes
Flashblock Update for Firefox 1.5
Non-Apple Wi-Fi Options Expand for Mac Users
Reality and Digital Pictures
Take Control News/12-Dec-05
Hot Topics in TidBITS Talk/12-Dec-05
<http://www.tidbits.com/tb-issues/TidBITS-809.html>
<ftp://ftp.tidbits.com/issues/2005/TidBITS#809_12-Dec-05.etx>
Copyright 2005 TidBITS: Reuse governed by Creative Commons license
<http://www.tidbits.com/terms/> Contact: <[EMAIL PROTECTED]>
---------------------------------------------------------------
This issue of TidBITS sponsored in part by:
* READERS LIKE YOU! Support TidBITS with a contribution today! <----- NEW!
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Special thanks this week to Edwin Simmers, Peter Tatikian,
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MailBITS/12-Dec-05
------------------
**Firefox 1.5 Released** -- The Mozilla Corporation has released
Firefox 1.5, the latest version of the popular open source
Web browser for Mac, Windows, and Linux. Important new features
include an automated update capability, improved navigation
performance, drag-and-drop reordering of tabs, improved
pop-up blocking, a one-step method of clearing private data,
more-descriptive error pages, automatic RSS discovery, better
accessibility, a wizard for reporting broken Web sites, enhanced
support for Mac OS X (including profile migration from Safari
and Internet Explorer), and numerous security enhancements.
Firefox 1.5 requires Mac OS X 10.2 or later and is a 9.4 MB
download.
<http://www.mozilla.com/firefox/>
Ironically after my article about simplifying installation in
TidBITS-807_, the Firefox disk image provides only graphical
instruction that's actively confusing. An arrow leads from
the Firefox icon itself to a smaller, greyed-out version of the
Firefox icon that is presumably being dragged, to judge from the
non-Mac-like pointer and + badge, and then to a greyed-out icon
that looks like the Applications folder. Unfortunately, it's all
representational - the Applications folder is just a picture,
and not a symbolic link, and there are no textual instructions
to clarify what to do. I've already heard of people not realizing
they had to copy the Firefox package and instead running it from
the disk image. Worse, the instructions on the Firefox Web site
say "double click the Firefox Disk Image to open it in Finder,
and then drag the Firefox application onto your hard disk.
Drag the icon to your Dock if you want it to appear there."
I'm sure there are people who will promptly drag the Firefox
icon from the disk image to the Dock, instead of copying it to
the Applications folder and then dragging the copied version's
icon to the Dock. Obviously, there's nothing all that hard here,
but that's no reason not to make it easier yet.
<http://db.tidbits.com/getbits.acgi?tbart=08346>
In comparison, applications that deserve kudos for using this
installation technique include Jim Matthews's Fetch (of course!),
James Thomson's PCalc, and Frank Reiff's A Better Finder Rename,
with extra points to Rainer Brockerhoff for using the technique
for his XRay utility since 2003. Some disk images don't force icon
view if the user has Open New Windows in Column View set in the
Finder preferences, which eliminates any graphical or textual help
that would otherwise appear. I'm not yet sure how to force icon
view in all situations. [ACE]
<http://www.fetchsoftworks.com/>
<http://www.pcalc.com/>
<http://www.publicspace.net/ABetterFinderRename/>
<http://www.brockerhoff.net/xray/>
[EMAIL PROTECTED] Moves to BOINC Client** -- If you're anything like me,
you don't pay much, if any, attention to [EMAIL PROTECTED] clients you may
have running on machines with CPU cycles to donate to the search
for extraterrestrial life. But Jim Carr, one of the top members
of the TidBITS SETI team, alerted me recently that the classic
[EMAIL PROTECTED] client is being turned off as of 15-Dec-05, and everyone
who wants to continue donating spare CPU cycles must move to the
new BOINC (Berkeley Open Infrastructure for Network Computing)
client that supports not just [EMAIL PROTECTED], but a variety of other
distributed computing projects. The [EMAIL PROTECTED] page has the
necessary instructions for downloading the latest BOINC client
and requesting your account information. Unfortunately, it's a
slightly obtuse process, and I wasn't able to convince BOINC to
attach to the [EMAIL PROTECTED] project, but the error message implied
temporary server problems (which the [EMAIL PROTECTED] folks have
mentioned on their news page). I recommend waiting a bit before
converting; either check the [EMAIL PROTECTED] site every so often to
see if they've resolved their technical difficulties or look for
another note in TidBITS. If you're new to the [EMAIL PROTECTED] project
and want to join the TidBITS team, follow the third link below
and click Join once there. [ACE]
<http://setiathome.berkeley.edu/>
<http://boinc.berkeley.edu/>
<http://setiathome.berkeley.edu/team_display.php?teamid=30293>
**DealBITS Drawing: GarageSale Winners** -- Congratulations to
Doug Breckenridge of gmail.com, Peter Pinch of rcn.com, and
Simon Sunatori of hyperinfo.ca, whose entries were chosen
randomly in last week's DealBITS drawing and who each received
a copy of iwascoding.com's GarageSale 1.9. Even if you didn't
win, you can save 20 percent off the purchase price of GarageSale
by placing an order using the third link below; this offer is
open to all TidBITS readers through 22-Dec-05. If you're planning
to attend Macworld Expo in San Francisco next month, you can find
iwascoding.com and GarageSale at booth 948. Thanks to the 612
people who entered, and keep an eye out for future DealBITS
drawings! [ACE]
<http://www.iwascoding.com/GarageSale/>
<http://www.tidbits.com/dealbits/iwascoding2/>
<http://order.kagi.com/?3W91&lang=en>
<http://db.tidbits.com/getbits.acgi?tbart=08344>
DealBITS Drawing: Classic Solitaire
-----------------------------------
by Adam C. Engst <[EMAIL PROTECTED]>
Solitaire card games have long been a mainstay of computer gaming,
especially for those who don't care for blood-and-guts first-
person shooters. If you're looking for an implementation of
Solitaire for the Mac, it's worth giving dogMelon's Classic
Solitaire a try, since it includes cards with professionally
designed graphics, 20 different Solitaire games and, most
important for those of us who have never even heard of games
like Idiot's Delight and La Grande Imperiale, an explanation
of the rules for each in the online help.
<http://www.dogmelon.com.au/sol/Mac_Solitaire.shtml>
In this week's DealBITS drawing, you can enter to win one of
five copies of Classic Solitaire, each worth $29.95. Entrants who
aren't among our lucky winners will receive a discount on Classic
Solitaire, so be sure to enter at the DealBITS page linked below.
All information gathered is covered by our comprehensive privacy
policy. Be careful with your spam filters, since you must be able
to receive email from my address to learn if you've won. Remember
too, that if someone you refer to this drawing wins, you'll
receive the same prize as a reward for spreading the word.
<http://www.tidbits.com/dealbits/classic-solitaire/>
<http://www.tidbits.com/about/privacy.html>
Prograph Spelled Backwards Is Marten
------------------------------------
by Matt Neuburg <[EMAIL PROTECTED]>
Prograph is back! Perhaps you have to be some kind of weird
programming nerd to think this is intriguing news, but personally
I think _anyone_ interested in programming, from a beginning
learner to an old hand, should care. Prograph is a wonderful
visual, dynamic, object-oriented programming language; instead of
writing lines of textual code, you draw a diagram of how you want
the data to flow. Not long after I reviewed it in 1996 ("Get Your
Hands on Prograph" in TidBITS-312_), Prograph started to wither
on the vine, and by the time Mac OS X came in, I had abandoned
all hope of ever using it again.
<http://db.tidbits.com/getbits.acgi?tbart=01160>
<http://en.wikipedia.org/wiki/Prograph>
It turns out, however, that what was withering was Pictorius's
product, Prograph CPX. The Prograph language itself is an idea,
and ideas are free. Unbeknownst to me, some nutty developers had
reverse-engineered the Prograph language and the Prograph CPX
environment, with a view to making Prograph available on BeOS.
When BeOS died, the effort was ported to Mac OS X and is now
available commercially under the name Marten.
<http://andescotia.com/products/marten/>
I haven't tried Marten, and I have no idea to what extent or how
easily it can be used to generate a native-looking application
on Mac OS X, but I am told that the Marten editor is itself
written in Marten, which is certainly something. And even if
it can't be used to write the next killer app, it's so enjoyable
and educational to express a task in the Prograph language and
environment that those who, like me, have been pining for it
will probably be more than happy to pay their $65 and give
it a shot.
NBC Universal Brings More TV to iTunes
--------------------------------------
by Mark H. Anbinder <[EMAIL PROTECTED]>
When Apple introduced its new video-capable iPod in October, the
early iTunes Music Store video offerings were limited to ABC and
Disney Channel television programs. Don't get me wrong, I like
"Desperate Housewives" and "Lost," but I yearned for this new
service to explore more of its potential. Last week's Apple
announcement of a deal with NBC Universal realizes that dream
for me.
<http://www.apple.com/pr/library/2005/dec/06nbc.html>
Now available is a much broader selection of entertainment,
featuring such NBC drama as "Law & Order" and "Surface,"
the nightly shows of Leno and Conan, science fiction
masterpiece "Battlestar Galactica" from the Sci-Fi Channel,
and the USA Network hit "Monk." But of more interest to me,
since I can already watch all of those shows via DISH Network,
is the collection of vintage NBC shows like "Adam-12," "Dragnet,"
and even "Knight Rider," plus the first season of "Law & Order."
<http://www.apple.com/itunes/videos/>
Episodes of each show are available for $1.99, with new episodes
available the day after they air on television. (Currently, TV
shows are available only in the U.S., and availability of other
videos varies by country.) Just as music albums often offer songs
for a total price lower than 99 cents each, TV series "seasons"
are typically available for a lower total price than $1.99 per
episode.
NBC Universal and Apple are cleverly taking advantage of the
recent surge in DVD sales of old TV shows. If you'll buy old
"Bewitched" episodes on DVD, why not grab an old "Alfred Hitchcock
Presents" episode to take on the morning commute? The programs are
all commercial-free, in contrast to announcements last month that
the NBC and CBS networks would offer 99-cent on-demand shows with
commercials via DirecTV and Comcast Digital Cable, respectively.
Noticeably absent is the NBC Nightly News Netcast with Brian
Williams, available for free in Windows Media format on MSNBC.com
each weeknight after 10 PM Eastern.
Apple says iTunes Music Store customers have purchased more than
three million videos since the service's debut less than two
months ago, for viewing in iTunes or the Front Row application
included with the latest iMac, or on an iPod. Add me to the
list; my first TV show download, of the long-ago pilot episode
of "Law & Order," is almost finished. Would you believe,
considering how many times a day "Law & Order" airs on TV,
I've never seen the pilot?
Flashblock Update for Firefox 1.5
---------------------------------
by Glenn Fleishman <[EMAIL PROTECTED]>
The Flashblock extension for Firefox lets you control whether
Flash animations automatically start playing on Web pages
(see "Firefox Flash Blocker" in TidBITS-794_). With the release
of Firefox 1.5, I was bereft! No update! Andrew Lawrence pointed
out via iChat that Flashblock had an update - the extension has
forked into two separate versions. For Firefox 1.0.x, you can
use Flashblock 1.3.3; for Firefox 1.5, Flashblock 1.5.
<http://flashblock.mozdev.org/>
<http://db.tidbits.com/getbits.acgi?tbart=08225>
Installing extensions within Firefox is a breeze:
1. Visit the Web page containing the extension.
2. Find the install link.
3. The extension should download (if it's blocked, see below);
click Install.
4. Quit Firefox and launch it again to load the extension.
If the extension doesn't download in Step 3, that's due to
Firefox's clever way of disallowing software installations
from sites you haven't approved.
Here's how to approve the site:
1. Click the download button or install button on the Web site.
2. A gray bar appears across the top of the Firefox browser
warning you the installation was blocked.
3. Click the Edit Options button at the far right of this
gray bar.
4. The domain name is prefilled in the pop-up window;
click Allow to add the domain to an approved list.
5. Click the Close button.
6. Try Step 1 again; if it works, go to Step 4 in the
installation steps.
Non-Apple Wi-Fi Options Expand for Mac Users
--------------------------------------------
by Glenn Fleishman <[EMAIL PROTECTED]>
The Taiwan-based chipmaker Ralink may be the solution for many
users of Mac OS X 10.4 Tiger trying to find a Wi-Fi adapter that
works with their particular machine. Although few companies make
Wi-Fi products that include or support Tiger drivers, several
companies use chips from Broadcom, Apple's Wi-Fi chip supplier,
which enables their products to work on a Mac without additional
software.
However, Broadcom's competitors have made inroads into the Wi-Fi
market, and some products that worked six months ago - for
instance, a Belkin 802.11g PCI Card - have been re-engineered
to save costs and no longer use Broadcom chips. Manufacturers
rarely directly disclose which chips are in which products to
avoid making promises about the underlying technology; they're
promising functionality (i.e., a Wi-Fi connection).
That's what makes Ralink's unsupported drivers for Mac OS X 10.2
through 10.4 and Linux so interesting: if you wind up with a
Ralink-based device, you can still use it with your Mac. Ralink
has been listening to its indirect Mac customers, because they
recently updated their drivers for Mac OS X 10.4 Tiger, and they
seem to release regular bug fix updates as well.
Ralink's driver page contains downloads for supported products,
but it's organized by internal chipset and product names. I hope
some enterprising soul will figure out which products and versions
from major makers use Ralink chips, expanding Mac users' options.
<http://www.ralinktech.com/supp-1.htm>
Belkin's 802.11g PCI Card (part number F5D7000) claims to have
Mac OS X 10.2 and 10.3 (not 10.4) compatibility on its detail
page, but doesn't offer drivers for download via the linked page.
Al Varnell wrote in point out that you must take a different
route to find drivers by visiting Belkin's download section and
navigating to the product. I have no idea why the drivers aren't
properly linked in both directions! The drivers were updated
in April, 2005 and include no mention of Tiger compatibility.
(Belkin also has Panther drivers for other products.)
<http://catalog.belkin.com/IWCatProductPage.process?Merchant_Id=1&;
Section_Id=&pcount=&Product_Id=136479>
<http://www.belkin.com/support/download/download.asp?category=9&;
lang=1&mode=>
There are now Tiger-supported USB 2.0 adapters for Macs - I found
this out almost by accident. The ZyXEL AG-225H, a Wi-Fi hotspot
detector with a built-in LCD screen, doubles as an 802.11a/b/g
adapter using USB 2.0. ZyXEL provides Mac drivers for both Panther
and Tiger; I haven't tested them but have been told that they work
by other Mac users. I reviewed the ZyXEL unit, looking primarily
at its Wi-Fi finding functions, for Mobile Pipeline back in
September, 2005. It's about $75 from several online retailers.
<http://us.zyxel.com/support/download.php>
<http://www.mobilepipeline.com/showArticle.jhtml?articleID=171000509>
Thanks to Dave Goldman for this tip!
Reality and Digital Pictures
----------------------------
by Charles Maurer
People often ask me if I think digital photography is as good as
film or will ever become as good as film. I reply that for all but
a few special purposes, digital is better already. Technically, my
digital photographs are at least as good as the best conventional
photographs I ever took with 2-1/4" x 3-1/4" (6 cm x 9 cm) film,
and pictorially they are better. With my digital camera I can take
pictures in the street that used to require a studio.
In this article I shall explain what digital technology can do
that conventional photography cannot - how computers can produce
more naturalistic pictures, not how they can produce special
effects. To do this I'm going to start with perception, pass
through art, and enter computers by the back door. Although this
is an unusual route, it approximates the way I think when taking
a photograph and it provides the only way I know for negotiating
the maze of manipulations offered by photo editors. Although I
shall mention some specific products (all of them available for
the Mac as well as Windows), I shall not describe any in depth.
The difficult part of digital photography is figuring out what
must be done in the computer and which application can do it.
Knowing that, it is rarely difficult to figure out how to make
the application do its job.
This article is illustrated with a number of pictures. To see
them appropriately, your monitor ought to be in rough calibration.
If you have never calibrated your monitor, I suggest that you do
it now. It takes about two minutes. Open the Displays preference
pane, click the Color tab, click Calibrate to launch the Display
Calibrator Assistant, select the Expert Mode checkbox, and then
follow the instructions. When you come to the screen asking you
to set the gamma, select 2.2.
For one reason that will become clear, I find some version of
Photoshop to be necessary. For this reason I shall assume its
use as a photo editor, although you need not own it to understand
the article. Along the way I shall mention the differences among
the last three versions (CS, CS2 and Elements) that matter for
my approach.
**Eye vs. Camera** -- To begin with, let's dispel the notion that
a camera records what the eye can see. It does not and it cannot
because a camera functions nothing like the eye. With a lens of
normal focal length, a camera records an image with a diameter
of approximately 45 degrees. It records the entire image at once
and the image ends up as a print with a range of intensity from
black to white of approximately one hundred to one. In contrast,
the eye sees an area about 180 degrees across but it sees most of
this with acuity that ranges from bad to dreadful. It sees sharply
just in the central 1 to 3 degrees. To see a scene clearly, the
eye must scan it and the brain must assemble the accumulated
information. However, the eye rarely has time to sample more than
small portions of a scene with its spot of clear vision so most
of what you see has no optical source, it is an inference. Your
brain infers information largely by generalizing from what it has
encountered before. In doing this the eye and brain have to handle
contrasts of light that exceed one million to one.
In short, when you look at a snapshot you took at the beach, the
limitations of the camera mean that three-quarters of the scene
will have been lopped off, the range of tones will be compressed
tenthousandfold, and the information that remains will never
be what you saw. Any appearance of realism will be an inference
informed by learning and shaped by convention. It is not realism
but verisimilitude.
Photographs may seem realistic but the technology of film prevents
escaping photographic conventions, which are actually quite
limiting. Less limiting is a paintbrush. A brush can produce every
effect a camera can plus a great many more. Before photography,
skilful and observant artists spent millennia working out how
to represent reality on flat surfaces using this superior tool.
Their work forms the most complete guide available on realistic
ways to put pictures onto paper.
Most artistic techniques cope with two basic problems, problems
that reflect the architecture of the visual tissue of the brain:
how to imply something about form and space using (1) areas of
brightness and (2) lines. These problems are not discrete and
isolated any more than the tissue of the brain is, they are two
sides of the same coin, but it will simplify our thinking to
make a fuzzy distinction between them.
**Contrast** -- The eye does not see light per se, it sees changes
in light - contrast. If two objects do not contrast with one
another, to the eye they meld into one. This fact makes
controlling the contrast of adjacent details to be paramount
in importance. However, the real contrast of any scene can
rarely be reproduced. As I said, the range of reflectance from
the lightest to the darkest objects in a scene is rarely less
than one thousand to one and often exceeds one million to one,
yet the range of reflectance of pigment against paper or canvas
is approximately one hundred to one. On the other hand, even
within a contrasty scene, small areas can have very little
contrast indeed.
From contrasting tones the brain infers three-dimensional objects.
It does this through association, by matching patterns it has
encountered before: a bright spot is a source of light, brilliant
yellow may be fire and hot, areas that are darker tend to be
removed from you or from light, bright areas tend to be near
you or near light, tiny highlights on a face indicate sweat and
heat, etc. To paint realistically, painters use associations
like these to create optical illusions. This is easy because the
eye scrutinizes only tiny areas at a time, so the brain cannot
easily compare colours and tones across broad distances. As long
as adjacent tones vary naturally, distant tones can be impossible
optically yet still look right. You can see this in Rembrandt's
painting of Belshazzar's Feast, linked below. The main source of
light on the faces appears to be the writing on the wall, yet it
is no brighter than the faces. It is not white but fiery gold, yet
it is so far away from his face that nobody notices the optical
absurdity. Also, with writing on the wall as the main light, the
secondary light reflected off the invisible wall on the left ought
logically to be much dimmer than it is.
<http://www.tidbits.com/resources/809/BelshazzarsFeast.jpg>
In other parts of the painting Rembrandt increased contrast where
he had to maneuver within too limited a range to limit himself
to variations in brightness. Look at the woman's red dress to see
an example. Not only do the folds look three-dimensional overall,
each tiny portion of every fold looks three-dimensional, even if
you restrict your eye to small areas, areas where there is little
difference in brightness from highlight to shadow. Every tiny part
of the dress contrasts with the part adjacent to it. Rembrandt
could do this because he did not vary brightness alone, he varied
hue and saturation as well - independently. If you open the
picture in Photoshop and set the Info window to HSB, you can move
the mouse around and see some of this variation that has survived
the miniaturization of the painting. (The real thing, which
somebody long ago trimmed to a smaller size and different angle,
is 66" by 82" or 167 cm by 209 cm.)
Filmmakers and commercial photographers create realistic photos
similarly, by "cheating" lamps that are put on the set as props,
lighting the set so that the light seems to be coming from those
props. An example is the picture of the blacksmith at the link
below. A logical analysis shows that no illumination can have come
from the fire, but the eye is not a logical analyser. However,
cheating like this takes more time than cheating on your taxes,
especially in a still photograph where the illusion does not flit
past your eye. That photograph took me a day to plan and a day to
execute. (Among other things, I needed to wrap the entire workshop
in aluminum foil, to prevent light from coming through chinks
in the walls.)
<http://www.tidbits.com/resources/809/Blacksmith.jpg>
On the other hand, equivalent results can often be obtained
without cheating by using a good digital camera and re-balancing
the light digitally. An example is the dyer in the picture linked
below. The version on the right shows the scene as film would
have caught it; the version on the left shows it as it felt
and as I remember it to be. It is probable that before I took
the picture, I noticed that the room light was bluer than the
firelight - I do tend to notice such things - but my overwhelming
perception was overwhelming heat and that heat is what I wanted
to portray. To the visual system, so many cues to heat are
present that the firelight in his face looks natural although
it's logically absurd.
<http://www.tidbits.com/resources/809/Dyer.jpg>
The next example shows a more ordinary picture. The image on
top shows what the scene looked like: a brightly lit bush in the
foreground with a jungle of trees in the hills behind, gradually
diminishing in size and clarity. However, although my brain
perceived the bush to be bright, it was actually dark compared
to the sky and the jungle was even darker. The scene presented
a range of tones that nothing man-made can come close to
reproducing. My camera's sensor "mechanically" compressed those
tones into the image on the bottom. Slide film would have done
the same. To make the picture look more realistic, I brightened
the bush in the foreground and painted contrast into the jungle
by varying saturation and brightness independently from each
other and from hue.
<http://www.tidbits.com/resources/809/Jungle.jpg>
To manipulate contrast in this way requires three things:
* Capturing the information that you want to bring out.
* Making that information visible by lightening shadows and/or
darkening highlights.
* Adjusting colour not to make it look accurate - that is
impossible - but to bring out whatever contrasts are necessary
to make it look right
To meet the first requirement, you need a raw, unprocessed image
(not a JPEG) from a camera that can record a broad range of
contrasts. In today's market this means a single-lens reflex
camera. (For more information, see the "Image Quality" section of
my article "Picking a Point-and-Shoot Camera: Panasonic DMC-FX7"
in TidBITS-783_.) When I convert the file to a standard format
(I prefer the generic TIFF to Adobe's PSD), I set its levels of
tonality to run the full extreme from black to white, with the
middle set to look as good as possible.
<http://db.tidbits.com/getbits.acgi?tbart=08136 >
Lightening shadows and darkening highlights comes next, with
Adobe's Shadows/Highlights control. Photoshop defines shadows
and highlights as dark or light areas larger than a certain
number of pixels across. CS, CS2 and Elements all enable adjusting
the amount of lightening or darkening but CS and CS2 also enable
adjusting the size of what Photoshop sees as a shadow or
highlight. I find that adjustment to be very important, and
I use it for maybe one photo in three.
(Most of what Adobe left out of Photoshop Elements I do not
care about - Elements is already more complex than it needs
to be - but I found this one adjustment almost reason enough
by itself to forgo Elements for the full Photoshop. The other
reason is that Elements has limited facilities to handle 16-bit
colour. Although 8-bit colour is usually sufficient, pulling
apart tonality often requires finer intermediate colours to
be present.)
Now look at the Rembrandt picture again, at the detail on
Belshazaar's cape. The detail stands out because it is formed
by brush-strokes with extremely high contrast from one to the
next, extremely high local contrast. I make detail stand out
in a photograph the same way by using an incidental feature of
PictureCode's Noise Ninja, which is primarily a noise-reduction
package (and one of the best). This feature is a slider that
enhances local contrast. I often use it by itself without any
noise reduction at all.
<http://www.tidbits.com/resources/809/BelshazzarsFeast.jpg>
<http://www.picturecode.com/>
Now comes the paint. If an artist wants to adjust a colour on
his canvas, he may change its hue, or he may daub on spots of
complementary colours to reduce its saturation, or he may add
some black or white touches to reduce or increase its brightness.
With digital photographs I want to do the same. The product
that enables me to do this is Asiva Shift+Gain.
<http://www.asiva.com/>
Shift+Gain is a Photoshop plug-in that lets you select areas or
lines (useful to remove colour fringing) by any combination of
hue, saturation, and brightness, and then alter those parameters
individually. No other product can do this, except for a stand-
alone package from Asiva that is too slow to use. Indeed,
incredible as it may sound, Asiva has a U.S. patent on this
approach to manipulating pictures.
Shift+Gain works differently from any other application and took
some time to understand. However, although it was confusing at
first, it soon came to seem simple. To accomplish in Photoshop
most of what I do in Shift+Gain would require far more skill
and patience than I can supply.
I find Shift+Gain to be an indispensable tool for digital
photography - the only indispensable tool, the only tool for
which I do not know of any functional equivalent. Unfortunately,
it will not work in any application other than Photoshop, not
even applications like GraphicConverter that can run most other
Photoshop plug-ins. It is compatible with any recent version
of Photoshop, but it does require Photoshop, which is why I
am ignoring possible alternatives to Photoshop in this article.
Those three sets of tools can handle nearly all the manipulations
of contrast and colour that I have had any need for: (1) the
controls in Photoshop CS/CS2 for levels, shadows and highlights,
(2) the local-contrast control in Noise Ninja, and (3) Asiva
Shift+Gain. Occasionally I also use one of Asiva's other plug-ins,
which work similarly but do slightly different things. I have
found that Asiva's plug-ins, combined with Photoshop's basic
selection tools, obviate the need for masking to achieve ordinary
pictorial effects.
Only one of Photoshop's colour adjustments do I find to be
particularly useful. Sometimes, after I have adjusted the
colours to bring out contrasts, the picture shows an overall tint.
Now, no tint exists on its own, a tint is merely an offset from
a standard of comparison. In a photograph, the eye's standard is
usually a pure white highlight or the paper's margin. If a neutral
white or grey looks coloured in comparison, then we see a tint.
Removing a tint is usually a simple matter of shading the picture
just enough to neutralize that white or grey. Every other colour
changes a bit, but the contrasts among them will remain. It's
difficult to remove a tint manually because the brain adapts so
readily to changes in colour that a wide range of adjustments
seems okay until you print out the picture. Photoshop can remove
a tint mechanically; the mechanism is hidden in the Match Color
command.
One final consideration about colour comes with dim light. In
sunlight we see in colour; in moonlight we see in monochrome;
in transitional "mesopic" levels of dim light we see partially
in monochrome and partially in colour. When painters want to
represent dim light, they portray it mesopically. You can see
this with the musician at the back of the Rembrandt and you
can see it even better in the Gross Clinic by Thomas Eakins,
the picture on the left at the link below. The students in the
shadows are nearly monochromatic but the monochrome contains hints
of colour, often quasi-random streaks and blotches. (Note that
the original painting is 96" by 78" or 243 cm by 198 cm.)
<http://www.tidbits.com/resources/809/GrossAbattoirFlowers.jpg>
Film does not portray dim light in this way, nor do most digital
sensors, but the Foveon sensor does. (See "Sense & Sensors
in Digital Photography" in TidBITS-751_ and my followup for
a discussion of sensor types.) Film and digital sensors generate
low levels of granular noise. When a normal amount of light
strikes the film or sensor, the noise is usually hidden within the
image, but when little light strikes it, the noise becomes more
evident. At some dim exposure to light the image disappears within
the noise: that defines the limit of sensitivity. The random dots
of this noise can be smoothed over but detail becomes smoothed
over with them and at the limit of sensitivity, all detail
disappears. However the Foveon image sensor works differently so
its granularity looks different. The Foveon shows fewer specks
but replaces them with intrusions of incorrect colour. At first
this reduces saturation then, at the lowest levels of sensitivity,
it causes random streaks and blotches.
<http://db.tidbits.com/getbits.acgi?tbart=07860>
<http://db.tidbits.com/getbits.acgi?tbart=07906>
Reduced saturation and random streaks and blotches of colour are
exactly the techniques that artists use to represent dim light,
and the Foveon's noise can be used to do the same. I smooth out
the granular noise with Noise Ninja - there is rarely so much of
this that Noise Ninja loses any detail - then I use Shift+Gain
on selected areas to control the discolouration. My goal is
sufficient discolouration to add contrast for the eye but not
so much as to be noticed. You can see the effect in the Chinese
abattoir to the right of the Gross Clinic painting you just
loaded.
Do note, though, that desaturation and blotchiness are not the
norm in Foveon photos. They are normally hidden in depths of black
and become evident only if you bring them out by pushing the
sensor to its limits. More normal is the picture of the flower
market - the third one on the page. I took both pictures indoors
and exposed them at ISO 1600.
**Perspective** -- So far we have been talking about how to
represent space using tonality, now let's shift to representing
space using lines. This is the problem of perspective.
During the Italian Renaissance, artists worked out a geometry of
linear perspective, geometry that appears superficially to fit
perceptual norms. In fact, however, it does not. The "laws" of
linear perspective need usually to be broken, else the picture
will look wrong.
The laws of perspective dictate that parallel receding lines
converge. They converge if they are receding horizontally like
railway tracks and they converge if they are receding vertically
like skyscrapers seen from the street. But consider vertical
perspective. If the angle of view portrayed is only a little bit
upward, then your brain may not infer that objects are converging
at a distance above you, your brain may infer that the objects
are not plumb. Of course, if those objects are walls of buildings,
then your brain concludes that they are not falling inwards, for
just as you assume that boards are straight, so do you assume that
walls are plumb. However, for the same reason - because you assume
that walls are plumb - buildings look more natural when all the
vertical lines are upright and parallel. You can see an example
of this issue in the two images of the temple pictured at the
link below. A correction like the top image with film would have
required the careful adjustment of a view camera on a tripod
but it took me two minutes in Photoshop. (Elements or CS can
fix perspective but CS2 makes it easier through a new Lens
Correction item in the Filter > Distort sub-menu.)
<http://www.tidbits.com/resources/809/VerticalLines.jpg>
The same adjustment is useful for horizontal lines. When
horizontal lines converge, buildings can appear to be constructed
on a hill and roofs can seem to have unusual inclines. To minimize
ambiguity, vertical lines ought to be plumb and horizontal lines
ought to be level unless the reason for them not to be is obvious.
Clear verticals and horizontals provide a frame of reference that
lets oblique lines stand out.
Pictures of buildings obviously benefit from this approach, but
often pictures of people do too, although more subtly. You can
see an example in these two pictures of children, linked below.
The picture on the top is stronger because the children are
sitting on a level platform, not a tilted one.
<http://www.tidbits.com/resources/809/Children.jpg>
In fact, the laws of linear perspective need to be violated even
when photographing something straight on. If you look straight
at a picket fence or a wall of bookshelves, an optically correct
perspective would have the lines of the fence or bookshelves
converging both to the left and to the right. This would look
so silly that nobody would paint them this way. For the same
reason, camera lenses are corrected to distort linear perspective
so that a rectilinear object casts a rectilinear image.
This presents an interesting problem that can be solved with
a brush or computer but not with film. The farther out from the
centre an object extends, the farther its lines will be pulled
apart and thus the more it will be enlarged, yet objects in
the centre will never be enlarged, distorting relative sizes.
The wider the lens's angle of view, the greater the distortion.
This distortion can be seen with any wide-angle lens and becomes
disproportionately more severe the wider the angle of view.
When straight lines are not involved - in many landscapes - it
often looks more natural when relative sizes are maintained at
the expense of convergence. This can be approximated in Photoshop
CS2 by adding convex "barrel" distortion, a distortion that
reduces the rectilinear correction of the lens.
(Note that only CS2 offers that control. CS2 also makes it
significantly easier than CS or Elements to correct converging
and tilting lines, once you find the new controls. In CS2, all of
the lens corrections are buried under Filters > Distort, although
File > Render still shows the subset of corrections that is shared
with CS and Elements.)
Of course, adding convex distortion is unacceptable if straight
lines are involved. A certain amount of convex distortion may not
be noticed in landscapes, but curvature stands out absurdly in
pictures containing buildings. An alternative fudge is to squeeze
the picture from the sides. To do this I use a $20 Photoshop
plug-in called Squeeze.
<http://www.theimagingfactory.com/>
I also ought to mention the portrayal of depth through having only
one plane of the picture in focus. This effect can be achieved
with a brush, but it rarely is, because it does not mirror what
the eye sees or the brain perceives. The eye sees only tiny spots
sharply, and it sees tiny spots wherever it looks: from these the
brain perceives infinite depth of field. To control attention and
suggest different qualities, a painter will vary the softness of
edges across a picture, but this variation is much more subtle
than a mis-focussed lens.
To vary hardness and softness within a picture, I used to use
a view camera that allowed me to tilt and swivel the lens, and
I varied the character of the light. A digital camera makes this
a lot easier. My digital camera usually provides infinite depth
of field with no special measures and I can use digital techniques
to control softness like a painter, as I did in the flower market
example previously shown. The flowers just behind the smiling girl
are soft, but the ferns behind them are sharp, as is every other
object in the picture except for the woman moving into it.
This was possible for two reasons, both tied to the camera's
image sensor. First, the ISO speed of negative film is based on
the least exposure necessary for acceptable snapshots. To extract
high quality usually requires doubling the metered exposure.
In contrast, to extract the best quality from my digital SLR,
I usually halve the exposure. That is two f-stops' difference,
which represents a lot of depth of field. On top of that, the
sensor in my camera is smaller than 35mm film, which means the
same f-stop gives more depth of field. The difference is 1-2/3
stops. Thus, for any given amount of light, I obtain nearly four
f-stops' more depth of field than I would get were I shooting
35mm negative film.
When everything is sharp within a photograph, photographic
compositions open up. People don't just look at my pictures,
they look inside them, combing them for detail - and they
find it, because I have controlled the details' contrast. With so
much information to look at, my 8" x 10" (A4) printer seemed too
small. Next week you can read a discussion of printers and my
search for a larger one.
Finally, to finish up my comparison of the various versions
of Photoshop, I ought to mention two new features of CS2 that
are useful for preparing enlargements, a "spot healing brush"
and "smart sharpening." The former I find to be a modest but
significant convenience, but the latter is an important feature.
It tightens up a lens's inescapable spreading of points into
blurry circles, and it reduces blur from movement. In my mind,
this feature combined with CS2's improved distortion controls
makes the upgrade from CS worth the purchase. I detest a Windows-
like copy-protection scheme that Adobe have begun to employ - it
prohibits the fair use of your purchase if you work in different
locations - but I swear at CS2 less often than I did at its
predecessors because it permits me to hide from sight the vast
number of menus that I never use and to edit or remove keyboard
shortcuts. With CS2, no longer do windows fly about the screen
and change their colour because one of my fingers inadvertently
touched a key.
PayBITS: If you found Charles's discussion of visual perception
and digital pictures useful, please support Doctors Without
Borders: <http://www.msf.org/msfinternational/donations/>
Read more about PayBITS: <http://www.tidbits.com/paybits/>
Take Control News/12-Dec-05
---------------------------
by Adam C. Engst <[EMAIL PROTECTED]>
**"Take Control of Mac OS X Backups" Updated to 1.2** -- Do you
have an effective strategy for backing up your work files, not
to mention your growing collection of iTunes purchases and digital
photos? Don't wait until disaster strikes. Get help now by reading
our latest release of "Take Control of Mac OS X Backups," which
has already helped thousands of Mac users. In this significant
1.2 update, you'll find the latest advice for developing a backup
strategy that fits your budget and style. The ebook now covers
the many changes made to backup hardware and software in the past
10 months, looks at Apple's Backup 3 for .Mac users, and offers
more than 20 pages of detailed directions for using the popular
Retrospect backup software. It also includes new sections about
backing up photos and video.
"Take Control of Mac OS X Backups" is now 138 pages and costs $10.
If you own an earlier version, you can download the update for
free by clicking the Check for Updates button in the lower-left
corner of your ebook's first page.
<http://www.takecontrolbooks.com/backup-macosx.html?14!pt=
TRK-0014-TB809-TCNEWS>
**"Take Control of Buying a Digital Camera" 2.0 Released** --
Anyone who wants to buy the right digital camera at the right
price can now find up-to-date info and more tips in the second
edition of "Take Control of Buying a Digital Camera," written
by Seattle-based professional photographer and instructor
Larry Chen. Larry walks readers through the entire purchase
process, providing help with budgeting and understanding what
types of photos you want to take, friendly advice about the
many possible camera features, expert guidance on reading camera
reviews and evaluating picture quality, and suggestions on
where to shop. The ebook, which we mentioned briefly last week,
comes packed with photography tips, case studies, and color
photos illustrating the discussions, plus a significantly
enhanced section about buying a digital SLR camera. Readers
will find a 2-page printable shopping worksheet, which they
can print out, annotate as they read, and take with them when
they shop. The ebook also includes an appendix summarizing popular
cameras in different categories and a glossary covering common
photography terms.
The second edition of "Take Control of Buying a Digital Camera"
has grown to 107 pages and costs $10, though it's 50 percent
off through 26-Dec-05 as part of our holiday consumer electronics
ebook sale. If you own the first edition, you can download the
update for free by clicking the Check for Updates button in
the lower-left corner of your ebook's first page.
<http://www.takecontrolbooks.com/buying-digicam.html?14!pt=
TRK-0015-TB809-TCNEWS>
Hot Topics in TidBITS Talk/12-Dec-05
------------------------------------
by TidBITS Staff <[EMAIL PROTECTED]>
The first link for each thread description points to the
traditional TidBITS Talk interface; the second link points to
the same discussion on our Web Crossing server, which provides
a different look and which may be faster.
**Applications folder symlinks ease installation** -- Readers
discuss various ways of installing applications more easily.
(8 messages)
<http://db.tidbits.com/getbits.acgi?tlkthrd=2807>
<http://emperor.tidbits.com/TidBITS/Talk/650/>
**Moving over user accounts without migration assistance** -- So
exactly how do you move a user account from an old Mac to a shiny
new one, without using Unix? (2 messages)
<http://db.tidbits.com/getbits.acgi?tlkthrd=2809>
<http://emperor.tidbits.com/TidBITS/Talk/654/>
**Bluetooth cell phones for Mac OS X** -- You're a Mac user and
you want a Bluetooth-capable cell phone that's compatible with
iSync and Salling Clicker, and that you can use as a modem to
connect to the Internet from your Mac. TidBITS Talk readers come
up with a couple of suggestions, but the pickings seem to be
slim. (3 messages)
<http://db.tidbits.com/getbits.acgi?tlkthrd=2811>
<http://emperor.tidbits.com/TidBITS/Talk/656/>
**New DRM causing problems playing audio CDs?** Is a Mac's
inability to play music CDs a new form of DRM or, more likely,
just a bad drive? (7 messages)
<http://db.tidbits.com/getbits.acgi?tlkthrd=2812>
<http://emperor.tidbits.com/TidBITS/Talk/657/>
$$
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