I've been playing with DNGPE making lots of ACR camera profiles for testing. I created a lot of files and a mess of the file names, so I tried renaming some "dcp" profiles. Found a problem and a mystery.
When I rename any profile that was created from the Adobe Standard base profile, all looks good. But when I rename a profile that was created from any other Adobe base profile (faithful, neutral, landscape, etc.) the renamed version behaves quite differently than the original.
When I apply the profiles in ACR, the renamed profile is brighter with more contrast than the original. The histogram stretches in both directions. The renamed profile looks like it has a different tone curve. The same thing happens if I take an Adobe profile, dupe it and rename it. A duped and renamed Adobe Standard profile looks the same as the original, a duped and renamed Camera Faithful profile does not.
I've used two separate tools to do the renaming. First the Xrite DNG ProfileManager, then DcpTools. With DcpTools, I decompiled the profile to xml format, editied that to change the name, then recompiled back to dcp. When I do that I get the following two messages:
Information: ReductionMatrix1 has zero dimensions
Information: ReductionMatrix2 has zero dimensions
However, I get those same messages if I just decompile and re-compile any profile without editing the xml. I've decompiled several original/renamed pairs and compared the xml files using a file difference utility. It shows no difference other than the profile name.
I've run DNGPE and loaded the renamed profiles as "base" profile so I could inspect the base tone curve. I see no difference in the base tone curve between the original and renamed profiles.
So I'm stuck with the mystery, looking for hints on what to try next.
How did I get here? I foolishly generated a series of profiles named "Temp1, Temp2... Temp5". Tested them and decided "Temp3" was the best. Then wanted to rename "Temp3" to something more meaningful. Not a big problem because I can easily regenerate "Temp3" with a proper name, but the mystery remains.