"Candelas Lumens and Lux" introduction to lighting  terms and calculations
"Candelas Lumens and Lux" introduction to lighting  terms and calculations




At last, a photometric file format in XML.

If you've ever struggled to get all the data about a luminaire from a IESNA format file or an Eulumdat format file you'll know how much information is missing. Even the updated IESNA format (IESNA-2002) does not have much more data than previous versions. While Eulumdat has remained mostly in its 1990 version. And both IES and LDT are pretty unstructured, and hard to read for humans. Here is an example IESNA file:

The LDT does not even have named fields, you have to go by line number. Here is an example Eulumdat file:

Because Eulumdat and IESNA files are so constricted, some companies "expand and re-interpret" them, with non standard extensions which only a few programs (mostly company internal programs) understand. These extensions often force more data into the lines than they were designed for.

LDT has another restriction, it is only for CG (internal and road) photometries, and cannot hold VH (external floodlight) photometries.

Luckily the OXL photometric file format has made it onto the scene. It is XML, so all fields are named and the inherent hierarchical structure means it is easy to add new fields which older programs can ignore.

Here is the start of an OXL file:

Not only does this format fill all the holes left by IESNA and Eulumdata, but being XML the the files can easily be read and written to and from online and offline database programs and apps.

The format is public, of course, so any company can use it without paying royalties (now or in the future) to OxyTech, who invented it.

While there are very specific technical documents on the OxyTech web site, in my view the best way to start to understand the OXL photometric file format is to read some and create some from your own LDT or IES files.

Click here to download some sample OXL files in a Zip file.

Click here to download and install LiteStar 10, which contains PhotoView. PhotoView is a program with which you can create and read OXL, LDT, IES files. After installation you'll find PhotoView in the OxyTech directory, which will look something like this (depending on your language):


OxyTech web site OXL links:

  1. OXL page at WebOxy.
  2. OXL Presentation.
  3. OXL examples as XML for the WEB.



(c) 2017
Contact me if you have any questions about this page or PhotoView photometric viewer. PhotoView is part of a set of services and programs from OxyTech which can be bought with a 10% discount. Click here to find out more.