Topaz Denoise 5 Review Part 2 – How to fix the magenta cast.

So the DPReview crowd has the usual whinging about the fact that I did not watch the videos to figure out how to process using this new version. What a silly concept. I complained about bad defaults, not a bad application. So here is how you fix that magenta cast.

First, load the same image and click RAW Strongest:

What you will see is that, unlike Denoise 4, the shadow slider has been pegged all the way to the right:

And you will see the Magenta cast on the whale:

It’s a simple matter now to dial back the “Adjust Shadow” slider to where it would have been on Denoise 4 … moving it back and forth in tiny increments, this 2/3 position is about where you get maximum noise reduction with no change in color.

Now that’s more like it. But since the only change is the “Adjust Shadow” slider, now I am curious about how Denoise 4 would handle me cranking that up.

Oops … it also pegs the slider at full, but does not muck with the contrast or colors.

 

Hmmm … ok, so let’s go back to Denoise 5 and try again. Leave the shadow slider pegged right and play with the new black level slider, which starts at 1.00, which should indicate that the setting is neutral but clearly indicates nothing of the sort. In inching it along from 0 to 1, I find myself wanting to leave it at 0. That seems to mimic what Denoise 4 does.

 

Yup, that’s the offender I it looks like. In fact, since either the “Adjust Shadow” or the “Correct Black Level” sliders can repair the problem, I think it is obvious that the two are not far apart in what they do -- and it kind of makes sense that black level has a lot to do with the appearance of shadows. :-)

So … I think Denoise should default black level correction to 0 so that the application does not harm your colors. It is not possible in Denoise 4 to cause this issue, because maxed out the Adjust Shadows slider is tame. But add the seconde control for black level in Denoise 5 and mayhem can ensue …

Here again is the Denoise 4 output:

And here is the adjusted Denoise 5 output with 0 black level. I also backed off the NR very slightly using the fade command, just toi restore the edges. Looks great.

So with this tweak, Denoise 5 looks as good as (and maybe slightly better than, but that requires more testing) Denoise 4 and runs about twice as fast. What’s not to like?