The Persistence of Vision Raytracer (POV-Ray).

This is the legacy Bug Tracking System for the POV-Ray project. Bugs listed here are being migrated to our github issue tracker. Please refer to that for new reports or updates to existing ones on this system.


FS#104 - Output file gamma broken for File_Gamma=1.0

Attached to Project: POV-Ray
Opened by Christoph Lipka (clipka) - Wednesday, 28 April 2010, 16:01 GMT
Last edited by Christoph Lipka (clipka) - Saturday, 19 June 2010, 01:14 GMT
Task Type Definite Bug
Category Frontend → Image format
Status Closed
Assigned To Christoph Lipka (clipka)
Operating System All
Severity Critical
Priority Urgent
Reported Version 3.70 beta 37
Due in Version 3.70 beta 37a
Due Date Undecided
Percent Complete 100%
Votes 0
Private No


Setting File_Gamma=1.0 produces unexpectedly bright output files for most output file formats, as if File_Gamma was set to 2.2 instead.

The underlying problem is a bug that, when File_Gamma is set to exactly 1.0, causes the encoding gamma function to be undefined, which was not meant to happen in current versions, and instead was reserved for future versions to signal that a file-format-specific default encoding gamma should be used. The image file output handlers already support this, most of them choosing the sRGB transfer function, giving roughly the same output as setting File_Gamma=2.2.

As a preliminary workaround, users may want to set File_Gamma=1.02 (any value smaller than 0.99 or greater than 1.01 should do).

This task depends upon

Closed by  Christoph Lipka (clipka)
Saturday, 19 June 2010, 01:14 GMT
Reason for closing:  Fixed
Additional comments about closing:  No further beta tester feedback for way over a month now; I consider that good news.
Comment by Christoph Lipka (clipka) - Wednesday, 28 April 2010, 16:50 GMT

fixed with change #4958.