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




Converting IESNA .IES files to Eulumdat .LDT files

In different countries different photometric file formats are used. The IESNA format is used in the US and has the .IES filename extension. EULUMDAT is used in Europe and has the .LDT filename extension. Other parts of the world have their own preferences, and it all means that a photometric viewer/converter is often needed.

With the PhotoView photometric viewer from OxyTech all you have to do is drag the .IES file into the program and save it as an Eulumdat file using the file menu.

Here is a screenshot of PhotoView:

Photometric file conversion program

(If you have a lot of files to convert you should look at the BATCH options of PhotoView.)

If you want to convert EULUMDAT to IESNA then the process is just the same. Drag the .LDT file into PhotoView and then use the File menu Save option to save it as a .IES file. Click here for even more explicit instructions.

In either case (.IES to .LDT or .LDT to .IES) you can change the properties and names of the photometries you are converting before you save them in the new format. PhotoView even has command line options for doing that in batch mode, if you have hundreds of photometric files to convert.

PhotoView is a flexible and modern Windows program for converting IES files to EULUMDAT and vice versa. It can convert (read and write and use data fields) from the following formats:

  1. IESNA:LM-63-1986
  2. IESNA:LM-63-1991
  3. IESNA:LM-63-1995
  4. IESNA:LM-63-2002

as shown in the save as IESNA dialog below:

converting from LDT to IES options

You can also see in the above dialog IESNA options for rotating the photometry (there are differences between Europe and the US on the exact meaning of C0 for example) and whether the photometry should be converted to an "Absolute Photometry" which is useful for LED luminaires and lamps.

Click here for details of discounts on PhotoView

If you are looking for a simple introduction to lighting concepts and calculations then have a look at Candelas Lumens and Lux:



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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.