mhoenicka

Emacs Photo Database now available

Wed, 14 May 2008 10:54:07 +0200

This is to announce that Emacs Photo Database is now available as a SourceForge-hosted project. As outlined previously, this is a database holding film, negative, and print information for photographers who use real darkrooms instead of digital cameras and a "lightroom".

Photo database front-end, 2nd try

Wed, 23 Apr 2008 22:44:06 +0200

I've reported previously that my attempts to create a simple photo database to manage my negatives and prints failed miserably with OpenOffice Base. I thought that installing a web frontend for SQLite might simplify adding and retrieving the data to a SQL database, but the results were not entirely to my taste. The tool simplified the database creation somewhat, and it is fairly easy to check the rows in the tables. However, there are two limitations:- if I need all information about a print - the print info, the negative info, and the film info - I have to join three tables. You can do this in the web interface as well, but only by typing the SQL query by hand - this isn't any simpler than doing it on the command line
- as the data are relational (each print belongs to a negative, and this in turn to a film), inserting data with the web interface isn't straightforward. You can easily fill in a form with the data of one table at a time, but you have to run separate queries to find the foreign keys that associate prints, negatives, and films.

I figured my photo database should be easier to manage than this. I recalled the ease with which I can retrieve an address or a phone number with my computer: switch to Emacs (it is open by default anyway), run "Alt-x rolo-grep", and there you go. Why shouldn't "Alt-x photo-find-negatives" provide the same convenience for my photo database?

As photo-mode would just be another front-end for a command-line application (sqlite3 in this case), I figured I could borrow some code from refdb-mode to get started real quick. And presto, within one-and-a-half days I had a feature-complete prototype running. Beat that with any tool or language other than Emacs Lisp.

Before describing how the system works, I'll have to recap how the data are organized. A film is either a 35mm/roll film or a set of sheet films which are developed together in the same tray using the same conditions. All development-related information, such as film type, developer type, developing conditions, goes into the t_film table. Each film may contain one to many negatives (the individual images). The exposure information, as well as a description and a foreign key that associates the negative with its film, go into the t_negative table. Finally I can make one or more prints from each negative. The paper type, exposure tricks, development conditions, and a foreign key which associates the print with a negative, go into the t_print table. I won't have to enter each individual print into this table, but rather different papers, exposure and development conditions that I try out while approaching the "perfect" print.

I settled for a unified naming scheme for each of the items which also simplifies data entry as will be described shortly. Film names look like "YYYYMMDD-XY" using the development date and a numerical suffix if I happen to develop more than one film per day. Each negative receives another two-digit number, i.e. "YYYYMMDD-XY-ZQ". The number ZQ corresponds to the position of the negative on the film roll or in the negative preserver (for sheet film). Each print (or rather print condition) receives yet another two-digit number, as in "YYYYMMDD-XY-ZQ-RS". This number on the back of each print is all it takes to find the relevant information in the database.

The database structure is defined as a SQL script. Run it through the sqlite3 command line client to generate an empty database.

As expected there are three sets of functions to enter new data, one for each table. In order to simplify entering several items at a time, each set has one function which creates an empty template (photo-create-film, photo-create-negative, photo-create-print), and another function that actually sends the data to the database (photo-add-film, photo-add-negative, photo-add-print). After creating and filling in a template, you can reuse it any number of times, so you'll have to change only the variant fields for similar datasets. photo-mode automatically inserts the appropriate foreign keys - all you need to specify is the negative (for print entry) or film (for negative entry) name - these are simple to remember due to the strict naming scheme.

Once the data are in the database, we'll need several functions to get at the data again. These functions are listed below:

- photo-find-negatives: searches the negative table for datasets that contain your search term in the location or description field. This is useful to find negatives if you know where they were taken, or what they show.
- photo-list-prints-of-negative, photo-list-prints-of-film: shows all prints that were made from a particular negative or film, respectively
- photo-print-info, photo-negative-info, photo-film-info: shows all information related to a particular print, negative, or film, respectively. The print query also displays the associated negative and film info. Accordingly, the negative query also displays the associated film info.
- photo-list-prints-of-film, photo-list-prints-of-negative: display a list of prints along with the negative description that were made from a particular film or negative, respectively.
- the preceding two categories also have equivalent functions that use a range of marked text, instead of text that you enter at the prompt, to retrieve the information. These functions are convenient to reuse matches returned by the *-find-* or *-list-* family of functions for further queries.

All this is coded in roughly 800 lines of Emacs Lisp. After some cleanup and writing brief instructions, I'll make the package available to the public, i.e. to all three photographers that are also fond of Emacs :-).

Installing SQLiteManager 1.2.0 on FreeBSD

Wed, 16 Apr 2008 01:59:47 +0200

I've been into b/w photography for at least 15 years now, and I've got a serious collection of negatives and prints. A rule of thumb says: the larger the format, the fewer images. As I'm using my 4x5 as much as possible, there's only a handful of negatives to add each year. Still, I'd like to keep track of the negatives and the prints in an easier way than I used to do so far: I scribbled the data onto legal pads and waded through them if I needed to look up something. This calls for some sort of database.First of all, conventional digital image databases are not up to the task. They are geared towards digital camera shots, but they cannot map a print to the corresponding negative, or the negative to the film (or batch of sheet films). However, I need just this in order to find the print exposure/development data, the film development data, and the negative exposure data associated with a given print.

I thought OpenOffice Base (2.3.1) would do the trick. Base is something like a MS Access clone, i.e. a front end with graphical tools to build tables, define relationships, and to create queries, forms, and reports. I might even be able to link the data to the scans of the negatives and prints which I keep on the computer anyway, and display them in a search form. I had to find out the hard way that Base is not even close to being usable, at least on FreeBSD. Whenever you do something interesting, it crashes reproducibly. I came across half a dozen ways to crash Base before being able to enter even a single complete dataset. As much as I like and rely upon the other OO tools, Base is ridiculous. I had to go back to a tried-and-true SQL database.

Although I usually don't shy away from command lines, a frontend would simplify data entry considerably. Think of issuing INSERT commands in tables containing a dozen fields or so. This is of course doable, but inconvenient. I came across SQLiteManager-1.2.0 which seemed to offer a simple and clean web interface to my tables.

The installation was far from smooth, although SQLiteManager is part of the FreeBSD ports collection (i.e. my box has the instructions to build and install the software from the original sources). SQLiteManager is a PHP5 web application which means a few additional hurdles on our way to eternal happiness. But lets go through the installation procedure step by step.

After installing the databases/sqlitemanager, databases/sqlite3, and /databases/php-sqlite3 ports (I intended to use version 3 databases right away), I had to edit the Apache config file manually:

Alias /sqlitemanager/ "/usr/local/www/sqlitemanager/"

AllowOverride None
Order allow,deny
Allow from all
AddType application/x-httpd-php .php .phtml

Running "apachectl restart" as root caused Apache to pick up the changes. Now I pointed my browser to "http://localhost/sqlitemanager/index.php" - and was greeted by a PHP error message saying something about missing session support. I recalled that FreeBSD needs an extra port (www/php5-session) to enable PHP sessions.

After restarting Apache and reloading the page, I got one step further, just to find out that there was no support for SQLite3 yet. I don't speak French, but the French installation instructions were clear enough to make me edit /usr/local/www/sqlitemanager/include/user_defined.inc.php to add the line

define("SQLITE3", true);

However, this was not sufficient. I happened to find the INSTALL file in the SQLiteManager installation directory which told me to install two additional database-related PHP ports: databases/php5-pdo and databases/php5-pdo_sqlite. With these in place (and Apache restarted), SQLiteManager offered SQLite3 support as well (watch out for the version numbers which are displayed on top of the start screen).

Now there was still a problem with file permissions. SQLiteManager keeps internal information in a SQLite database of its own. The INSTALL file already mentioned to set the permissions appropriately. On FreeBSD, Apache (and thus PHP scripts as part of a web interface) runs as user:group www:www. I changed the group of /usr/local/www/sqlitemanager/include/config.db (and of config3.db, although the installation instructions didn't mention it) to "www" and added write permissions for group members. However, I still got errors saying the config database is not writable. I recalled that in order to write to a file, you'll also have to write to the directory that contains the file in order to update the timestamp and the size information. Therefore I had to change the group and change the permissions of /usr/local/www/sqlitemanager/include as well.

It wasn't immediately apparent how to create a new database from scratch. The interface won't tell, and the (French) manual was of limited use as well. I finally figured that you have to enter a short database name (which will then be displayed on the left hand side of the web interface) in the upper field and a full path to the database file in the lower field. This file does not necessarily have to carry the same name as the display name. SQLiteManager of course needs write permissions in the target directory in order to create databases. To this end, I created /usr/local/var/db/sqlitemanager, changed the group to "www" and added write permissions for group members. I'd then use this directory to hold all database files created with SQLiteManager.

Finally, with less than 2 h of hairpulling, I was able to add my first table and start some serious work. I'll probably get back with further comments once I have gained some experience in handling my data with this interface.

How to connect your liver to your heart with a toothpick

Wed, 19 Sep 2007 14:20:10 +0200

Here's another one in our ongoing series of how to harm yourself by eating toothpicks.

A 55-year old man reported to the hospital with chest pain and a difficulty to breathe when not at rest. The pain was also noticeable when he was lying on his right side. The patient also suffered from a loss of appetite, accompanied by a loss of weight, and did not feel well in general. He was diagnosed with a massive pericardial effusion (a loss of blood from the heart to the surrounding tissue) and a constrictive pericarditis (an inflammation of the sac surrounding the heart). The patient was taken to a computer tomograph which confirmed the pericardial effusion and additionally detected an abscess of the left side of the liver. The scan also showed a tubular structure connecting the liver and the heart which was obviously of foreign origin. A laparotomy (surgical opening of the belly) revealed a wooden toothpick that somehow made its way out of the bowel, through the liver, and partially into the heart. The toothpick was removed and the patient recovered within a week.

The paper also contains a brief literature search which reveals that only 12% of the patients treated for symptoms of a toothpick gone the wrong way remember swallowing that toothpick. That is, only one in about 10 people eating toothpicks are aware of the fact. On the other hand, 80-90% of the cases where people remember swallowing a toothpick are uneventful. Clearly, there are situations that make you less aware of what you put in your mouth (think alcohol), but it still makes me wonder how absentminded you have to be in order not to notice. But then - shit happens.

Cutting Carbon VI

Wed, 19 Sep 2007 12:28:48 +0200

Now that my electrical power is generated without carbon dioxide emissions, there is one last source of greenhouse gases that I can do something about: my car. I commute almost every weekend to see my kids, and unfortunately the only reasonable way to get there is to go by car.

The carbon dioxide emissions of a car are directly linked to its fuel consumption. I should probably explain two terms here. In continental Europe, the gas consumption is expressed as liters of fuel per 100km. That is, a fuel-efficient car consumes less fuel to get you 100km from here. In the US, and afaik in Great Britain as well, you determine the mileage, that is the distance that you can travel with a gallon of fuel. Thus a fuel-efficient car has a higher mileage.

There have been a few serious attempts by the car industry to build fuel-efficient cars. One of them is a nice example of how not to do it. The Volkswagen company used to build a small car called the Lupo. In 1999 the Lupo 3L hit the market. "3L" doesn't denote the engine size here (which was 1.2 liter, by the way), but the fuel consumption per 100km. The 3 cylinder turbo diesel engine thus had a US mileage of 78. This translates to a carbon dioxide emission of 81g per kilometer.

This was indeed a technical feat, but the car didn't exactly sell well:

- it was very small. You could use either four seats and essentially have no trunk, or you'd use two seats and fold down the back seat to create a trunk large enough to hold a few shopping bags.
- it was tricky to drive at times as the car was too light when occupied by a single person. Early models had to be retrofitted with lead weights in the rear bumper to put enough weight on the rear axle.
- it was butt ugly, as if it had written "don't buy me" across the hood.

Technically this was the car that the Smart should have been, but the Volkswagen managers apparently tried to sell it only to those who'd otherwise be eco-friendly enough to walk by foot. In any case, the Lupo 3L was discontinued in 2004 after merely 27000 units were sold. At around the same time, Volkswagen introduced the luxury sedan Phaeton (the top model sporting a 6 liter engine that consumes 14,5 liter gas per 100km / 17 miles per gallon, releasing 348g carbon dioxide per kilometer) and the luxury SUV Touareg (top model: same engine, using 15,7 liter per 100km / 15.5 miles per gallon, releasing 382g carbon dioxide per kilometer). Both of them were considered a success, and especially the latter sold well. So much about us fighting the climate change.

My Ford Mondeo station wagon was about 10 years old and due for a replacement anyway. Not that it was broken down, but the corrosion got noticeable and a lot of minor things like the shocks and the muffler would eventually have to be replaced. I went shopping for a preowned car that fulfilled these requirements:

- about 2-3 years old with no more than about 30000km (approx. 19000 miles)
- large enough to transport a bicycle without hassles
- Euro 4 or better emission standard
- lowest fuel consumption / highest mileage of its class

It was pretty clear from the start that my new car would be quite a bit smaller than the Mondeo, and that I'd have to switch to a diesel engine to get the lowest fuel consumption possible. It was also clear that only a station wagon would be suitable for my purposes. There were a few cars to consider:

- Opel Astra
- Renault Laguna
- Ford Focus
- Skoda Octavia

And the winner is... disclosed in a future post.

Cutting Carbon V

Mon, 30 Apr 2007 09:41:44 +0200

Call me stupid, but last week I went to my utility company and asked them to charge more for my electricity. The reason is not a terminal loss of common sense, but I wanted to switch to a tariff that is based solely on renewable energy sources. The default tariff that I had paid for so far uses an energy mix consisting of 34% nuclear power (this alone was a reason to switch), 45% fossil fuels (mainly coal and gas), and only 21% renewable sources like water, wind, or solar energy. The new tariff, which takes effect on May 1st, uses 100% renewable sources throughout. I've calculated that I'll have to pay an extra EUR 2.50 (approx. USD 3.00) each month for this extra peace of mind. Think about that. The equivalent of one glass of beer a month.

Of course, switching the tariff doesn't make my radio blast louder or change the light from my light bulbs. Also, it's not like all "good" electrons arrive in my household and the "bad" ones in my neighbor's. Most utilities don't run all power plants themselves, but they purchase some or all electric power as needed from companies running such plants. Now that I pay more for the same amount of electrical power, the company is obliged to purchase more power from a supplier that runs on renewable energy sources only. Last year's bill shows that I consume approx. 740kWh of electrical power per year (before I started to cut my carbon dioxide emissions). Switching the tariff thus avoids 0.37 gram (0.013oz) of radioactive waste (there is no secure storage facility in Germany, so each milligram is one too much) as well as 169.5 kg (374lb) of carbon dioxide emissions per year. In other words, 18 Euro-Cent (approx. 23 US-Cent) keep 1 kg of carbon dioxide from entering the atmosphere.

Cutting Carbon IV

Fri, 20 Apr 2007 10:19:27 +0200

Barely 100 years ago, ice was cut from glaciers to be sold in cities like Munich. The affluent were thus able to cool food (or beer!) during summer. The ice was put into sort of a closet, and the old-fashioned German word "Eisschrank" (ice cabinet) for fridge nicely describes the original mode of operation.

We're better off these days. Everyone has a fridge at home. Just plug it in and off you go. As fridges need to remain cool all time, they consume a considerable amount of energy, which gives me another chance to cut down on my carbon dioxide emissions.

I had a small fridge with a freezing compartment in my kitchen which was left over when my parents remodelled their home years ago. I just recently learned that this unit must be approximately 30 years old. It was still running, but not very efficiently. During summer you'd notice a stream of hot air coming from the heat exchanger, and it was running almost continuously in hot weather. I went shopping for a new, energy-efficient unit and purchased a comparable unit. According to the specs this one uses 172kWh per year. Cheaper units of the same size use up to 250kWh per year.

My old unit was probably a little worse than that when it was new. Let's assume that it used 350kWh per year because it was worn out after 30 years. Replacing the unit will thus reduce my energy consumption by approximately 180kWh per year. This amounts to saving EUR 29.00 (USD 37.00) per year. Buying the new unit will thus pay off within 8 years. Using my current tariff, I'll prevent 41 kg of carbon dioxide emissions as well as 90 mg of radioactive waste each year. Needless to say, the new fridge looks better and is a lot cleaner (duh!).

Cutting Carbon III

Thu, 19 Apr 2007 20:55:59 +0200

Today I finished testing a new appliance at home. I like to start the evening with a cup of espresso or cappuccino. I'm using one of these stove-top pressure brewers that are one of the most ingenious inventions from Italy. Unfortunately, the diameter of that espresso maker is approx. 8cm (3in), whereas my smallest hot plate measures 15 cm (almost 6in) in diameter. If you compare the footprint of the espresso maker (50 sq cm) with the hot plate surface area (177 sq cm) it is easy to see that two thirds of my hot plate heat the room instead of the espresso. About time to do something.

I managed to locate a tiny hot plate with a diameter of barely 10cm. Needless to say, the hot plate is made in Italy. I've been told that many stoves in Italy indeed have such a small hot plate built in just to brew coffee. In any case, I tried whether the small hot plate was up to the task and if using this thing translates into energy savings.

First I prepared a cup of cappuccino the traditional way. The 1500W hot plate heats the water to the boil in 4 min. As the plate is large enough to heat up some milk (which is then whipped with a small battery-operated gadget) at the same time, this is all it takes in terms of electricity.

Next I used the small hot plate. It takes 6 min to brew the coffee with this 450W device. As the plate remains hot for quite a while, it is not a problem to remove the coffeemaker and use the remaining heat to warm the milk after unplugging the plate (the thingy is so simple it doesn't even have a switch).

Now let's do the math. The traditional way uses 1500W x 0.067h = 100Wh. The new plate uses 450W x 0.1h = 45Wh. That is, using the small plate saves more than 50% of energy. Lets assume I drink 250 cups of cappuccino a year. The savings amount to 250 x 55Wh = 13.8kWh a year. Using my current eletricity tariff (more about this in a later post), this translates into 3.15 kg of carbon dioxide and 7 mg of radioactive waste that I can save each year by simply using a different hot plate. The coffee tastes all the same, as far as I can tell.

Cutting Carbon II

Tue, 17 Apr 2007 13:41:05 +0200

Yesterday I checked all my sockets again. I usually take care not to leave appliances in standby mode. The cheaper the appliance, the higher the risk it burns several watt 24h a day just in order to receive a wake-up call from a remote control once per day. I use power strips with switches to conveniently turn on my stereo or my computer equipment. It is really not that hard to walk up to the equipment once a day instead of pressing a button on the remote control (besides, my amplifier was built before Joe Sixpack could afford remote controls). However, scrutiny revealed that I had plugged in the transformer of a desk lamp into a power strip that was not switched off by the main computer equipment strip. As transformers consume some energy even if the secondary circuit (the lamp in this case) is switched off, I was accidentally burning a few watt for nothing. The same happened with a small transistor radio. To avoid using rechargeable batteries I used a small ac/dc power supply, but this was also directly plugged into a socket.

Now I can switch off the transformers of both the lamp and the radio. I doubt that I'll see an influence on my bills, but doing it this way certainly doesn't hurt. There's nothing like this warm fuzzy feeling of cutting your carbon emissions...especially if it boils down to using the proper socket.

Cutting Carbon

Fri, 13 Apr 2007 10:51:14 +0200

Carbon isn't a bad thing at all. As a matter of fact, you can't live without it, as almost any kind of food contains carbon galore. Animals exhale carbon dioxide, but at the same rate plants fix carbon dioxide and use it as a building block to increase their biomass. Without a healthy dose of carbon dioxide and other greenhouse gases our planet would be a cold, unpleasant place that would not be able to sustain the life that we know: the energy-rich short wavelength rays of the sun pass the atmosphere almost unhindered, but the resulting longer wavelength radiation emitted by the earth's surface is partly absorbed by the atmosphere, causing it to warm up.

However, too much of a good thing isn't good either. Currently mankind releases more carbon dioxide than plants are able to capture, causing the greenhouse effect to become more efficient than necessary. In addition, other carbon-containing gases like methane (cattle burps and farts are a major source) worsen the situation. Most of us agree that something has to happen, except maybe a few nations that see pollution as an unalienable right.

I'm not going to dream up an elaborate plan that is going to save the earth. Instead, I'd like to share a few thoughts how everyone can help to reduce carbon dioxide emissions without sacrificing their lifestyle. I personally believe that it does not make any sense to wait for a bunch of diplomats to agree on large-scale plans which are inevitably overturned by reality. Instead, I prefer to do whatever I can do now, no matter how small the contribution is.

Today's installment provides a calculation of the amount of carbon dioxide which I don't release by riding a bike to go to work instead of using my car. We have about three months of sub-freezing or near-freezing temperatures over here. We have lots of rain during spring and autumn. My workplace is on top of a hill, approx. 100 vertical meters (300 ft) higher than where I live. There's 4 kilometers (approx. 2.5 miles) to go from home to work. Lots of excuses to not use a bike, but I still do. My car isn't exactly a gas guzzler, but it still releases 273 gram of carbon dioxide per 100 kilometers in the city (187 gram average). There are an estimated 240 workdays per year, equivalent to (4+4)*240=1920 kilometers (1200 miles) per year. That is, riding my bike prevents roughly 525 kilogram (1160 lb) of carbon dioxide, the mass of half a car, from entering the atmosphere each year. Besides, it is a nice workout and an effective way to make your brain wake up in the morning.