Image Noise Reduction Workflow Tip
One of the most common image enhancement workflow questions we get over here is...
At what point in my post-processing workflow should I apply noise reduction?
Why, excellent question! This is actually a very important factor in the quality of the resulting image, whether you use built-in Photoshop noise reduction tools or astoundingly good third-party noise reduction software. When to apply noise reduction is one of the most important and most overlooked aspects of effective image enhancement.
The simple answer is to apply noise reduction before applying ANY other adjustments to the image.
This includes JPEG compression, Camera RAW or even in-camera noise reduction, sharpening, exposure adjustments, dodging and burning, "Psychedelic" presets, whatever. See, in order to differentiate between noise and detail, noise reduction software have a very specific idea of what "noise" looks like and what "detail" looks like straight out of the camera. Applying any kind of adjustments to the image confuses the noise reduction software and causes it to give you a subpar result.
Demonstration time! Consider the following thousand words:
Canon 40D: f/2.8, 1/160, 1600 ISO
The image is very noisy and a little bit underexposed. I processed it a couple of different ways to illustrate the point of this post:
1. Original image, 2. Exposure then DeNoise, 3. DeNoise then exposure
Feel free to click on the images for larger versions. The first version only has exposure adjustments - in this case Levels - applied to it. Oh no noise! 1600 ISO underexposed isn't pretty.
In the second version, I took the RAW file and first corrected the exposure adjustment and then applied noise reduction. In the final version, I applied noise reduction as the very first step in my workflow before exposure correction. The results speak for themselves - and this was just a simple exposure adjustment!
Next time you really need to get the best results on your noise reduction, keep this in mind: no matter what noise reduction software you use, it's always important to apply it first. I'd go as far as to turn off the built-in noise reduction and sharpening functions in Camera RAW before you import into Photoshop for best results.
I've heard of plenty of advice given where noise reduction is put at the end of the workflow together with sharpening. Although this may be convenient, if you're really looking for great results, put noise reduction smack at the beginning of your post-processing workflow before you touch a single pixel.
July 24th, 2009 - 01:19
Great Eric…
I Can Hardly wait until you Finish DeNoise for use on my Raw Images in LightRoom
Thanks Monty
July 24th, 2009 - 07:23
Good tip!
I found Topaz Denoise’s “Auto bright” very handy in this aspect. It allows see to see the noise reduction result at dark area without the need to adjust it first.
July 25th, 2009 - 02:49
Thanks Monty! Yes, we’re working on that and it should be out very shortly
It will definitely improve the Lightroom PP workflow a lot, that’s for sure.
July 27th, 2009 - 09:54
It makes a lot of sense putting noise resuction as the very first step, but what about HDR’s. That process will more than likely apply additional noise even if it comes in clean. Do you suggest that you apply it again after running it through the tone process?
July 27th, 2009 - 14:53
That’s a good question, Jack. The best quality way would be to take your RAW exposures and run them through your noise reduction software first. Then, combine the noiseless exposures in whatever HDR software you use.
That would be the absolute best way, but for HDRs that workflow may be a bit wonky. Combining them first and then removing noise will produce an acceptable result as well. Although it won’t completely match the quality of the first way, it is a lot fast and more convenient. It’s up to you which method works best!
(I will add that it’s better if you only use one pass of noise reduction, however, for the same reasons listed in the post. Otherwise the second pass gets confused by the first one, even if it’s from the same software.)
Best,
Eric
July 30th, 2009 - 12:57
I’m loving this plugin much better than what I have been using. If I want to do each of the noise reduction steps, ie, luma, color, noise, details, reduce blur, remove clr specks,etc. on a separate layer so I could paint in the effect as needed for each part of the picture, what would be the best order to do that in?
July 30th, 2009 - 14:39
What I would personally do, Charlotte, is actually just apply the entire plug-in to different parts of the image and then mask them in individually. Noise reduction software tend to evaluate noise levels holistically and don’t work well when all its functions are separated.
Let’s say you have an image with three parts to it: 1) an extremely noisy portion that was severely underexposed, 2) a slightly blurred area with very minor noise, 3) a portion with lots of color noise. Just apply the denoise filter 3 times on 3 layers, each time adjusting the settings for just one of the image portions. Afterwards, mask those layers in for whichever area of the image they correspond to.
In my opinion that would be the best way. Things may get messy when you deconstruct the noise reduction algorithms by separating each function into an individual layer.
July 30th, 2009 - 18:21
For a complete and understandable (yet very long) explanation about how to apply topaz Denoise, you can check out this tutorial.
I was created with a challenging image taken at whooping ISO 25600.
There is an explanation step by step on how and when attack each king of noise.
http://www.flickr.com/groups/topaz/discuss/72157620377073337/
September 26th, 2009 - 19:13
I am fairly to Topaz, especially with all these choices, but not new to shooting sports. Can you recommend which product would work best for night sports photography and also indoor sports? Thanks. Examples would be even better!
September 26th, 2009 - 19:14
I am fairly new to Topaz, especially with all these choices getting kind of confusing to me, but I’m not new to shooting sports – I’m “old school”. Can you recommend which product would work best for night sports photography and also indoor sports? Thanks. Examples would be even better!