RouseWorld | Main -- August 2004 Archives

The expanded RouseWorld

Personal entries like this can be kinda gross, but I do want to let everyone know what is going on. So if you do want to know what's been going on, click on through.

If you don't want to, there is a new Wayward Packet article available.

My own private false-color Saturn

So I've been going to the Cassini-Huygens site, digging all the articles and pictures of the "Frigid Ringworld." Now as cool as the natural color images are, why be stuck with natural?

I went into the raw images and found quite a few grayscale images of the same subject, just with different filters in front of the camera. The different filters show different kinds of detail and different contrasts, similar to the differences between the Red, Blue and Green channels of an RGB image.

So I took a few of the filtered pictures and assigned them to different color channels of a single picture in Photoshop. Using RGB channels gave me very odd results, so I created a CMYK image, which gave a much more subtle result — although still not natural.

Another issue was registration, I had to make sure that the different color channels were aligned, or the image would look blurred.

At the end I just converted to RGB and saved out as a JPG image.

So what do you think?

Experiments in the LAB

I decided to go for a more wild look for Saturn, and I wanted to work in the LAB color space. Choosing LAB made things more difficult, as the color ranges go into negative values for the 'a' and 'b' channels, instead of the standard eight-bit 0-255. So when I dropped in a filtered grayscale image the dark areas actually rendered deep blue instead of space black.

To get space black back, I had to reduce the shadow contrast in half on the 'a' and 'b' channels. That brought the black back, but it also warped the colors in the rest of the image. I fiddled with the levels to get things wild, but not too wild — but then I started loosing gradients in the highlights. I also picked up an odd vertical stripe pattern from somewhere. Sigh.

Oh well ... I put it up on the 'Art Gallery' anyway.