alan little’s weblog archive for july 2003

photoshop file sizes

1st August 2003 permanent link

This post will be slightly off-topic from what I’ve been writing about in this weblog so far. I’ve had separate subject area blogs for quite a while, which were really more semi-private notebooks - I was keeping them for my own use and didn’t really care if anybody else read them or not. Now I’m experimenting with mixing everything up together in one public weblog.

Which means I am, with a fairly clear conscience, about to talk about an obscure Adobe Photoshop issue that I would previously have put in my photography notebook/blog. It could be worse - at least I’m not jumping straight from Mac browsers and the relative merits of python and java as real world programming environments, to the finer points of some yoga asana I’m having difficulty with. (You wouldn’t believe how obscure that can get. I’m an active member of a couple of yoga discussion boards where arguments about the precise angle of the pelvis in a particular backbend, or all the possible implications of the sanskrit word atha (now), can go on for days)

Meanwhile, safely back to the technical - some thoughts on the use of high bit images in photoshop. High bit images is a term photoshop types use to refer to images with 16 bits per colour per pixel instead of the usual 8. And surely more data == better?


Working with 16 bit images has a non-drawback, and a drawback. The non-drawback is that they’re twice the size of 8-bit images. But so what? Memory is cheap and disk space is almost free. A few years ago when I was working for IBM, I was involved in a project to build a terabyte data warehouse, which cost several million pounds and at the time was one of the largest in Europe. Now I have over a quarter of a terabyte in my living room. And I want a LaCie Big Disk, which would bring the total storage capacity of Alan’s Data Center to over 800 gigabytes.

Let’s say a gigabyte of disk space costs about a US dollar and a 35mm picture, scanned at 4800 dpi and 8 bits per channel, is a hundred megabytes (these are right-order-of-magnitude approximations for ease of arithmetic). A 16 bit scan, therefore, is two hundred megabytes, or ten cents worth of disk space more than the 8 bit scan. If it even crosses my mind whether to save the larger file or not, then I’ve just wasted more than ten cents worth of time. And in a few years when disks have 100 times more capacity, that ten cents will be a tenth of a cent.

Memory isn’t as cheap as disk space, but I have a gigabyte and a half on my photoshop machine and that’s more than enough to work on the biggest 16 bit files my scanner is capable of producing.

The real drawback of working with 16 bit files is that you’re severely limited as to what you can do with them in photoshop. You can’t use the smart selection tools to pick out precise areas, and you can’t use layers to make changes. Layers allow you to switch your changes on and off at will in any permutation, without doing anything irreversible to the original image. They are the overwhelming advantage to working with 8 bit images. (They also substantially increase the size of your 8 bit file, back up to what a 16 bit version would have been or more - another reason why file size is a non-issue)

But quality takes precedence over speed & convenience. And more bit depth must mean better quality - I can do subtler colour corrections, with smoother results, if I have 64k tones to play with in every channel than if only I have 256. Right?

Wrong, apparently, according to The Photoshop High-Bit Advantage: Fact or Fiction. The author Jim Rich asked pre-press professionals and photographers at a conference to distinguish between prints of 8 and 16 bit images, using images he had specifically chosen to show up the potential weaknesses of 8 bit processing, and edited far more drastically than usual. And they couldn’t. They admitted they were guessing, and nobody got more than 60% of them right. Whatever theoretical advantage 16 bit images may have just isn’t visible to the naked eye, even if it’s the naked eye of an experienced graphics professional.

So maybe I should forego the comfortable feeling I get from those lovely big 16 bit files, and accept that the practical benefits of editing with layers are more important than the theoretical benefit of having more subtle colour gradations that I can’t actually see.

related entries: Photography

photoshop tutorials

1st August 2003 permanent link

Another entry that really belongs in my photography notebook, but that I'm going to put in here anyway (to make it look like I'm writing lots of stuff) is a link to this excellent photoshop sharpening tutorial by Thom Hogan, which I found whilst looking for things to give my brother to supplement the "three years of photoshop experience in three hours" seminar I did for him earlier in the week.

While I'm on the subject I might as well plug a couple of other photography websites with good photoshop tutorials and loads of other interesting stuff: Michael Reichmann's Luminous Landscape and Ian Lyons' Computer Darkroom. Michael and Ian are both good guys - knowledgeable, friendly and helpful. I'm in discussions with Michael about publishing a major photography article that I've written.

related entries: Photography

a busy day

31st July 2003 permanent link

From the “I don’t know how I ever find time to have a job” department - the last few days have been reasonably typical of trying to get things done whilst not having a nice quiet office to get them done in. My brother is over visiting from England for a few days: mainly to meet his new nephew, but he also has a new digicam (the sexy Canon S50 that seems to be everybody’s darling lately). He wants to use it to publicise his picture framing business (no website to link to yet - another item on the to-do list) and he asked me to give him some some basic tuition in digital photography and photoshop. So Tuesday morning started with two hours of “Digital Imaging Basics 2 - scanning and dust spotting negatives”. Class interspersed with pauses at regular intervals to sing to and otherwise amuse the baby. Today will be “Digital Imaging Basics 3 - photoshop colour correction in one hour”. Ha. It took me over two years to really get to grips with that and I still find it difficult.

(And when my brother gets home with my old Nikon LS-30 film scanner that I’m donating to his cause, he’s also going to need somebody to take him through “SCSI Card Installation For Musicians & Artists”. I really don’t want to be the telephone tutor for that class.)

At 10:30 my next student arrived - the son of a friend, who is supposed to be having difficulty with English at school and needs some remedial classes over the summer. Artur is twelve, he emigrated from Russia to Germany four years ago and already speaks pretty much perfect German. After an hour conversing with him in English and getting to know him, I’m thinking that if this guy is getting bottom-but-one grades and is in need of remedial classes, then the standard of English required of twelve year olds in German schools must really be frighteningly high. Tomorrow we actually look at his books and start going through the bits that the letter from his teacher says are unsatisfactory. I just hope I’ll be able to do them.

After lunch we have to trek into town to visit a Bavarian state official and get a stamp on a document that forms part of the endless paper trail of my son’s various potential citizenships. (English father, Russian mother, born in Germany). Excellent chance for my brother to practice his uncling skills by taking the baby for a walk while we wait around in offices. (More coaching required - we decide the bare minimum he needs to survive if he is approached by old ladies asking about the baby is “I am his uncle, but I don’t speak German”). By the time we’re finished with Mr. Bureaucrat it’s suddenly four o’clock. How did that happen?

more mac market share

26th July 2003 permanent link

In my article on browser market share I said I wasn't aware of any figures for the installed based of Macs. Well, As the Apple Turns is not only always fun, but also occasionally comes up with useful quasi-statistics, like these ones yesterday.

Microsoft apparently claims to have 600 million customers [a mere 10% of the population of the world - how can that be an unassailable monopoly?] of whom the boys & girls at AtAT conservatively assume 90% are Windows users = 540 million Windows users. Apple, meanwhile, believes there are 25 million Macs out there - which if my calculator isn't mistaken means Mac users are about 4.4% of the Windows + Mac installed base(*). Which - finally getting to the point - means that's 10% of Mac-using visitors is on the high side as I suspected it might be.

(*) Assume desktop Linux is statistically insignificant, which is probably true now but might not be for much longer [big pdf link].

related entries: Mac

python and java (and perl)

26th July 2003 permanent link

Russell Beattie has written a couple of articles recently on python from a java programmer's perspective. I haven't put as much time and effort into trying out python as Russell has - in fact, I gave up and went back to java pretty quickly, because that way I could be productive instead of spending hours and days banging my head against the kind of frustrations Russell has written about.

My previous consulting gig finished at the end of June, and with all the time I suddenly had available (in an apartment with a six week old baby - ha!) I decided to get moving with a couple of programming projects I've wanted to do for a while - an analyser for my web server logs, and a weblog tool. (Yes, I know there are dozens of both readily available, many of which are free and open source, but that's not the point ...). I've been thinking for some time that it would be nice to learn python, and one or both of these seemed like an ideal easy-but-interesting starter project. On the other hand, I hadn't used java for a while and from a looking-for-employment point of view I thought it might not be a bad idea to brush that up a bit. Nevertheless, I decided to start with python - which I had already played with a bit using Mark Pilgrim's excellent Dive Into Python - on the basis that it's a nicer language. I still think it is, but read on ...

First I needed to get my development environment set up with various tools that I knew I was going to need. I'm used to perl, where tools to help with anything you could possibly want to do are available on cpan and you just download them - or, if you're on Windows, you just fire up activestate's excellent module installer and it does everything for you. Or java, where most of what you want is in the standard libaries and if you do need something third party, such as the excellent JFreeChart, you just put a couple of .jar files in the right place, read the javadoc and away you go.

With python, it doesn't seem to be like that. I wanted to hook python up to MySQL. There doesn't seem to be anything to do that in the standard modules that are available on So I did a search on google and got pointed to the home page of the guy who wrote something called mysqldb, but when I went there it said the current version had moved to sourceforge. I downloaded it from sourceforge. It didn't build. Firstly because, oops, no gcc. I had forgotten I had installed the Apple developer tools on the laptop, but now I was on the desktop which had previously spent its working life as a photoshop workstation. I downloaded the latest developer tools. Fair enough, if I need a C compiler then I need a C compiler - but I've never had to bugger about with C compilers to install a simple perl or java library to do something as fundamental as talking to a database. The MySQL thingie still wouldn't build. I googled the error message (something bizarre from gcc about being asked to build i386 code and not wanting to, which I suppose is within its rights if it knows it's running on a Mac), and found somebody who said he had submitted the fixes to for OS X to the developer months ago (but they're still not in the supposedly latest version that I had just got from sourceforge). I made the fixes. It built, but still didn't actually work when I fired up python and tried to use it.

I googled some more, and found a link to another page suggesting some different fixes to get to work properly on OS X. The page wasn't there any more. I grabbed it from the google cache. Haven't tried it yet though, the whole experience so far has just been too depressing and discouraging and meanwhile I've been busy actually getting work done in java.

I know it's always frustrating getting to know a new development environment - I've learned enough over the years to know I should budget at least a full day mucking about with stupid configuration settings before I can actually get anything productive done. But the impression I'm getting so far is that python the environment is like perl the language - powerful but messy, inconsistent and a certain amount of aggravation and trial & error required. (Whereas perl the environment is like python the language - things are generally clean, elegant and it Just Works)

Meanwhile I already have a working version of the log analyser and have made a start on the weblogging tool (which isn't generating this page yet but will be in a day or so, baby permitting) using java, which is frustratingly verbose and irritatingly pedantic with its type and exception checking, but also Works.

related entries: Programming

mac market share

25th July 2003 permanent link

In my article on browser market share I mentioned Apple's latest 2.3% share of new PC sales. John Gruber at Daring Fireball has some (as always) intelligent comments on why that 2.3% figure isn't as low as it seems - in short, Apple isn't even trying to compete in large chunks of the market (low end commodity PCs, big corporate accounts) and has a far higher share of the market it is competing in - high end sales to discerning individuals.

related entries: Mac

mehr Linux, mehr Freiheit

24th July 2003 permanent link

mehr Linux, mehr Freiheit

“More Linux, more Freedom” is a poster for the Bavarian state parliament election that I spotted the other day in the Schwabing district of Munich. I’m neither a Linux user nor a supporter of the SPD, but I do find it mildly interesting that a politician thinks Linux versus Microsoft is an issue that the electorate knows and cares about.

Of course, the city of Munich has just made a very high profile decision to adopt Linux as the desktop platform for 14,000 workers. (numerous links from Philip Windley. Joel Spolsky is sceptical. (Actually, my main reaction is to look at that 14,000 figure and find it alarming that over one percent of the entire population of my current home town work as bureaucrats for the city council. Perhaps I’m just naïve about what it takes to run a large modern city)

more on browsers

24th July 2003 permanent link

Tim Bray : "the proportion of IE users here at ongoing recently crossed the 60% line, heading down". And a recent user survey at arstechnica had 41% of respondents using OS X or Linux as their "primary OS".

I'm a little sceptical of the arstechnica result because it came from a user survey, and I strongly suspect that people (such as Mac and Linux users) who see themselves as a righteous and oppressed minority are likely to over-report themselves in surveys. Vote early, vote often. Nevertheless, arstechnica is a hard-core technical site and therefore likely to attract a high proportion of Linux users. And it has a good Macintosh discussion forum that presumably also attracts technically aware OS X users. As Tim O'Reilly pointed out last year, technical people who appreciate the benefits of life on a stable Unix platform with a good user interface are flocking to OS X. (At least, those technical people who have enough money to believe that the benefits outweigh the drawback of overpriced, underpowered hardware. Until next month, at any rate)

I'm sure Tim Bray's readers are also a fair sample of where the technical leading edge is going., on the other hand, can make no such claim. Over 90% of our yoga-and-photography audience still uses Internet Explorer.

traffic to

24th July 2003 permanent link

I've been doing some analysis of the visitors to, and thought the results could conceivably be of interest to somebody.

First, to establish my credentials as the owner of a small, obscure website with a statistically insignificant amount of log traffic to analyse, here's a chart of page views per month since the beginning of in October 2000.

total page views

Traffic has been growing steadily - or had been up until the last couple of months, when I became a father and didn't have time to write anything any more. In total I have around 1.1 million raw hits in my logs, of which around 200,000 represent successful views of html pages by what appear to be real people using browsers. (The rest are errors, page views by robots and hits on image files - the latter are a high proportion of all hits because much of the site is a photo gallery)

What browsers are my human viewers using?

page views by browser

No surprises there. Netscape 4 is rapidly dying out but most of its share is being taken by Internet Explorer. Modern standards-compliant browsers like Mozilla and Safari are only increasing slowly, although Mozilla has finally overtaken Netscape 4 as the number two browser. (I do also get some hits from other minor browsers like Opera and OmniWeb, but I've excluded anything with under one percent share from the charts to avoid clutter)

I'm particularly interested in what percentage of viewers I'm getting using Macs. I bought my first mac this time last year and have been very happy with it. I've also suspected for quite a while that the subject matter of my website, primarily photography and yoga, might appeal to a disproportionately Mac-using audience.

page views by platform

Well, my share of page views by Mac users is around 10%, which is certainly significantly higher than Apple's market share of new computer sold (2.3% in the US, the last I heard) and probably somewhat higher than their share of installed base (I'm guessing - haven't seen any reliable estimates for the Apple installed base figure). On the other hand, it's gently-but-steadily declining as Windows gently-but-steadily increases, and Linux and other Unix variants remain insignificant. (I would be interested in being able to distinguish between OS X and Mac Classic visitors, but I don't know how to do that reliably using User Agent Strings.)

The browser picture on the Mac is somewhat different.

page views by browser (Macintosh)

Netscape 4 was still close to parity with Internet Explorer on the Mac two years ago, but already declining rapidly. But on the Mac, Internet Explorer market share has levelled off and a lot Netscape 4's traffic share is being taken by Mozilla and, more recently, Safari. Let's take a closer look at the bottom right hand corner of that last chart - what's been happening with non-IE browsers on the Mac since the beginning of last year.

non-IE Mac browsers

The most striking features is Safari's rapid rise to the number 2 position with 15% share. Safari seems to have killed off Omniweb. Chimera seems to have been completely stillborn - which is a pity, I liked Chimera and used it as my standard Mac browser for a while before I switched to Safari. Hence why I chose to count it separately from other Mozilla variants - those Chimera hits are probably all me. It will be interesting to watch what happens with Safari over the next few months, particularly once it starts shipping as the standard browser on new Macs.

notes, definitions & assumptions

I'm a novice at do-it-yourself http log analysis. I used to use analog for basic statistics, but I got frustrated with it because it can't produce any cross-category reports like "browser share by platform", so decided to write my own. I have a little java programme that parses my server log files and writes them into a MySQL database where I can do ad hoc reports and analysis of whatever I happen to be interested in. Using a database would probably be unacceptably slow if I was running a millions-of-hits-an-hour site, but as we've already established, I'm not and I like the flexibility it gives me.

Here are the assumptions and definitions that the figures above are based on (some of which may be wrong):

related entries: Programming

first weblog post

24th July 2003 permanent link

I've been thinking it's time to start a weblog for a while now. But first I thought ok, but I want to write my own blogging tool and host it on my own server. And then I thought fine, in the meantime while I'm building that I can something started with blogger - oh but then I have to write some kind of some kind of killer first post. But not being able to do that also isn't a good reason not to start writing something.

(Actually, it's time to start a weblog again . I kept an online diary last year when I was in India. And I've used blogger as a web-based personal notebook for various things for a while.)

(It turns out blogger doesn't seem to want to publish from Safari these days, so I'm writing by hand for the time being until I get the homegrown publishing system working)

Now I really need to get going on that software or lose all technical credibility, given the sudden fashion for pointing out just what a trivial technical challenge weblogs are (Tim Oren, Brian Tiemann, Tim Bray)

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