WARM!
Today is one of those days where the world forgets that it is January, and we get several days of Spring weather. All the snow melts, the world is wet, and then it starts to dry. Result - today is a wonderful day! The temperature is about 20C (68F) out today, and I just got back from a walk without jacket. Last night I ran with lightweight tights, and I was TOO HOT. Not bad for the 7th of January!
Of course, all things will come to an end. But that is OK, mini-vacation had, now back to reality.
Tuesday, January 08, 2008
The hot tub is fixed! The hot tub is fixed!
This may not be exciting for anyone else, but for me it is! As many know, I love my Softub hot tub. But over a year ago, it broke - the motor stopped working.
Well, after several lesser fix attempts (involving two filling / empty cycles in the process), I finally replaced the motor / pump assembly. Then put it back together, filled it with water, and.... it slowly leaked :-(
Next I replaced the gaskets - filled it back up, and it still leaked.
Finally I consented to having the hot tub store replace the liner - it apparently had grown old and developed some microcracks. I got it back about 2 weeks ago, filled it, and..... the motor didn't work!
OK, drained it, diagnosed it, and found that it was a problem with the ground-fault breaker. Fixed that, filled it and now it is fine (or at least as best I can tell).
Yesterday I used it 3 times! Happy Chuck! Happy ending!
This may not be exciting for anyone else, but for me it is! As many know, I love my Softub hot tub. But over a year ago, it broke - the motor stopped working.
Well, after several lesser fix attempts (involving two filling / empty cycles in the process), I finally replaced the motor / pump assembly. Then put it back together, filled it with water, and.... it slowly leaked :-(
Next I replaced the gaskets - filled it back up, and it still leaked.
Finally I consented to having the hot tub store replace the liner - it apparently had grown old and developed some microcracks. I got it back about 2 weeks ago, filled it, and..... the motor didn't work!
OK, drained it, diagnosed it, and found that it was a problem with the ground-fault breaker. Fixed that, filled it and now it is fine (or at least as best I can tell).
Yesterday I used it 3 times! Happy Chuck! Happy ending!
Tuesday, January 01, 2008
Photographic color rendition under varying illuminants
Sorry once again for the non-fun blog. This will stop soon, promise...
I always wanted to do this experiment - take a sample, photograph it under several different light sources, correct the white balance for each, and once this is done, see how much different things look in the corrected photographs. From a practical standpoint, this translates to "how important is it to use daylight to photograph art or a still life?".
I am going to skip the discussion of color rendering index (CRI) and other related topics - if you don't know what they are, you probably aren't reading this anyways... Some day I'll perhaps provide at least some references. Meanwhile, on to the experiment.
G, my watercolor paint swatch obsessive wife, unwittingly provided a color test target - full strength tube watercolor paints. My goal was to take three nearly identical photographs, varying only the light source.
The first light source is the reference standard - mid-day daylight, in this case natural light under a cloudy sky (no direct sunlight of the target). The second source was a compact fluorescent light fixture (sorry, don't know the model) with a specified 5000K, 91 CRI 70W bulb (actually three 23 w. bulbs combined). Finally, I used a quartz halogen source. For this, I started with a halogen flood lamp, but didn't like the light distribution, instead using two 75w halogen floor lamp fixtures.
The targets were photographed using a Nikon D80 at f8, 50 mm, using Nikon RAW mode. Once the images were captured, Adobe Camera Raw was used to convert the images to Adobe RGB files. The following procedure was used for each image:
First, the reference daylight picture:
Next, the Halogen picture:
Sorry once again for the non-fun blog. This will stop soon, promise...
I always wanted to do this experiment - take a sample, photograph it under several different light sources, correct the white balance for each, and once this is done, see how much different things look in the corrected photographs. From a practical standpoint, this translates to "how important is it to use daylight to photograph art or a still life?".
I am going to skip the discussion of color rendering index (CRI) and other related topics - if you don't know what they are, you probably aren't reading this anyways... Some day I'll perhaps provide at least some references. Meanwhile, on to the experiment.
G, my watercolor paint swatch obsessive wife, unwittingly provided a color test target - full strength tube watercolor paints. My goal was to take three nearly identical photographs, varying only the light source.
The first light source is the reference standard - mid-day daylight, in this case natural light under a cloudy sky (no direct sunlight of the target). The second source was a compact fluorescent light fixture (sorry, don't know the model) with a specified 5000K, 91 CRI 70W bulb (actually three 23 w. bulbs combined). Finally, I used a quartz halogen source. For this, I started with a halogen flood lamp, but didn't like the light distribution, instead using two 75w halogen floor lamp fixtures.
The targets were photographed using a Nikon D80 at f8, 50 mm, using Nikon RAW mode. Once the images were captured, Adobe Camera Raw was used to convert the images to Adobe RGB files. The following procedure was used for each image:
- Set the white balance using the white center of the color wheel. This is done by clicking in ACR with the white balance eyedropper.
- Set the exposure (essentially adjusting the histogram) as follows: view in threshold mode, and advance exposure until the first sign of clipping (this always happened in the oranges, but the paper white, interestingly enough...), then back off .05 exposure units.
- Rotate and crop the images so they are approximately the same size.
- Specify a conversion to Adobe RBG (which provides a wider gamut than sRGB). Then, for web viewing, (the picures you will be viewing below), also convert a copy to sRGB mode and save as a separate .jpg.
No other manipulation was done in Photoshop, save adding a text layer to identify the light source. So, here are the three resultant pictures:
First, the reference daylight picture:
Next, the Halogen picture:
Finally, the High color rendering index Fluorescent lamp:
Analysis - lots of thoughts, lots of things to say, no hard conclusions - but those will have to wait for a bit, as it is now time for bed....
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