Experimental music, photography, and adventures

Archive for the 'Geek' Category

Scanning cross-processed negatives

Wednesday, December 5th, 2007

My first attempts at scanning cross-processed negatives with my cheap flatbed scanner were plagued by a strange yellow color cast. (By “cross-processed,” I mean E6 slide film processed in regular C41 print chemicals.) The yellow color cast was an interesting effect, but the colors weren’t even close to those in the prints. I tried using the Levels tool in Photoshop to adjust the white balance, but it just didn’t work. After thinking about it for a while, I came up with a solution.

Smith and Third
First attempt

Smith Road and Third Street
Better scan

The trick I discovered is to set my scanner to Positive mode (usually used for slides), even though the image I want is negative. After scanning the image, I invert it. Then, I use the Levels tool, sometimes hitting Auto Levels and sometimes doing it manually, to get the exposure I want. I also adjust the white balance sometimes; in this case, I clicked on the white minivan to get the colors as neutral as possible. Since it’s cross-processed, the colors still look funky.

This technique seemed counterintuitive at first because inverting an image twice yields the image you started with. However, this is not the same as inverting an image twice.

In regular color negatives, the film has an orange mask, and my scanner compensates for the orange mask when set to Negative scanning mode. Cross-processing slide film leads to a negative image, but without the orange mask. So, in Negative mode, my scanner was attempting to compensate for a non-existent orange mask. Setting the scanner to Positive bypasses the mask compensation, giving accurate colors — you just have to invert the image.

A couple more examples:


Bicycle on bridge

Barn II


Power loss detected

Friday, June 8th, 2007

I just got a disturbing message in a terminal session while working. Nothing seems out of whack, the UPS apparently did its job, but it’s still a bit nerve-wracking:

Broadcast message from root Fri JunĀ  8 11:17:29 2007…

Warning power loss detected on UPS ups4

Broadcast message from root Fri JunĀ  8 11:17:33 2007…

Power has returned on UPS ups4…

This week’s rides

Friday, May 4th, 2007

My commutes this week have been fantastic, especially in the mornings. It’s mostly been cool most mornings, with some sunny and some overcast days, and it just feels great to ride. One day this week, I even woke up in a good mood (that never happens).

Motorists have been pretty courteous, and I’ve ridden at a different pace each day depending on my mood. Sometimes, it’s nice to take my time, and others, I feel like riding harder. I always try to keep from riding too hard, though, so I don’t work up too much of a sweat. That’s getting more and more difficult as it gets warmer, especially with the high humidity we have here. I also had a commute home in the rain that was not bad at all — sure, I was wet when I got home, but my bike works in the rain, and so do my legs.

I haven’t driven to work in well over a month, and it feels great. A few times, I’ve thought about driving, but those were fleeting thoughts. I really see no reason to drive, unless it’s raining in the morning. I don’t mind getting wet on the way home, but I don’t want to show up at work drenched. So I’ve worked from home at a couple of opportune times when I might have otherwise driven because of rain. I need to find a long-term solution to this, which may simply mean putting a towel in my pannier.

My mileage is a bit low this week because of the rain we’ve had, but I’ve managed to squeeze in a couple of road rides. I also messed around with my new digital point & shoot camera that I got specifically to take on hikes, bike rides, etc — complete with a warranty that covers accidental damage. Taking a cue from A Midnight Rider, I signed up for a PhotoBucket account and made a “remix” with some of my photos from last night’s ride on Mount Gilead Rd. I also used the Flock Web browser to help do a batch upload — it was very slick, allowing me to take images right out of my camera, rotate/crop if needed, and upload a bunch at once. It also supports Flickr. The “remix” is basically a slideshow set to music, but unfortunately, you can only pick from certain songs they have available. Anyway, check it out below, assuming this works at all.

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