Archives for the ‘Graphics’ Category

Visualizing LUT data in Blender

This animated cube contains the data in a 3D LUT: A Look-Up Table, as the name describes, is simply a large table of numbers. Given an input color RᵢGᵢBᵢ, you simply go to the corresponding row in the table and find your new color RⱼGⱼBⱼ. Each dot in the video is an RGB values (each […]

HDR light probes for cheap

TL;DR: A Ricoh Theta S can be had for under $60 on eBay. Combined with pfstools, you can easily capture HDRI environment maps and merge them into OpenEXR images. The Ricoh Theta S is Ricoh’s cheapest 360-degree camera that has automatic bracketing functionality. I bought mine for about $60 on eBay second-hand. The image quality […]

Is Krita ready for HDR painting?

Right this minute, you can open up Krita and start a new document in linear ACEScg with either 16fp or 32fp encoding. And it works! You can open floating-point OpenEXR files or use the color picker to choose colors like RGB[3.5, 3.0, 1.5] where normally you would be limited to 0.0–1.0. You can paint in […]

Workaround for HipChat on Linux: “can’t find build id”, “HashElfTextSection”

The new version of HipChat added support for video and screen-sharing. It also introduced the new requirement of OpenGL 2.0. On my computer, HipChat would crash on startup with repeated messages of [code] can’t find build id HashElfTextSection can’t find build id HashElfTextSection can’t find build id HashElfTextSection can’t find build id HashElfTextSection [/code] I […]

Batch organize photos by date

I wanted to get a pile of jpegs organized by the year, and then the day. For example, IMG00001.JPG would go in 2013/06-04 based on its EXIF creation date. The handy exiftool can do this, via its own virtual “Directory” tag. The “Directory” tag is not an actual EXIF tag, but exiftool will move the […]

Convert video with subtitles to MP4 for iPhone/iPad (preliminary notes)

By now, we know of a few requirements for viewing video on iOS (iPhone/iPad et al.). The video codec should be H.264 or another “standard” MPEG codec, and the audio should be AAC. AC3, as far as I know, is not supported. That’s all fine and dandy, but subtitles have been one of the trickiest […]

Command-line snippets for processing scans

I originally wrote this in 2009 as a cheatsheet for processing black and white scanned sheet music. It’s a collection of tips for converting and processing scanned images to ultimately get a nice, high-quality PDF that you could archive. The programs convert and mogrify are part of the ImageMagick suite and the program pdfimages is […]

How to scan like a pro

Scanners have been around for a long time, and today’s scanners are cheap, are fast, and produce high-quality output. Still, people haven’t figured how to make good scans—just take a look at scanned scores, manga, etc.—from their scanners. This means the difference between: and Guide follows: