When do you do noise reduction?

Wilba wrote:

Following from other discusssions of noise and using tools to reduce it,
I'm interested in when in your process do you do it.

For instance, I can apply NR in ACR, in Photoshop (e.g. Noise Ninja)
before resizing, after resizing but before sharpening, or after
sharpening. If you only did it once, when would you do it? Do you do it
more than once, when?

Thanks for all the replies. The general consensus is to reduce noise early,
as I suspected it would be.

I just played around with a typical image with those tools and found that I
got the best results, considering both noise and detail, by setting NR to
zero in ACR and using Noise Ninja. The advantage appears to remain after
downsizing (typically 4272x2848 - 1000x670), but is barely perceptible
before sharpening and maybe a touch more after. And yes, sometimes no NR is
better for how I want an image to look.

I've no doubt I could do better with a lot more work, but just doing that
puts me ahead of where I was. Thanks again.

David J. Littleboy wrote:
"Alan Browne" wrote:
Wilba wrote:
Following from other discusssions of noise and using tools to reduce it,
I'm interested in when in your process do you do it.

For instance, I can apply NR in ACR, in Photoshop (e.g. Noise Ninja)
before resizing, after resizing but before sharpening, or after
sharpening. If you only did it once, when would you do it? Do you do it
more than once, when?
Definitely before sharpening at production size.

Really. I hope, but haven't figured out whether or not, Lightroom gets this
right.

Mostly before re-sizing (but I'd like to hear other opinions).

I vote for NR _before_ downsizing. This has the advantage of reducing
aliasing.

I'm not sure about upsizing. I'd think that you really shouldn't be upsizing
images that need NRg.

Good point. I mostly downsize, but occasionally upsize.


(I don't use it much at all).

For B&W film scans, it's pretty much necessary.

Once it's printed, it hardly matters.

"ColinD" wrote in message
...
Wilba wrote:
Following from other discusssions of noise and using tools to reduce it,
I'm interested in when in your process do you do it.

For instance, I can apply NR in ACR, in Photoshop (e.g. Noise Ninja)
before resizing, after resizing but before sharpening, or after
sharpening. If you only did it once, when would you do it? Do you do it
more than once, when?

Thanks, W
I am a DxO Optics afficionado, and DxO reduces noise during 'developing'
the raw image, using data specific to the camera sensor and ISO speed
used, which is coded into the camera model by DxO. Gives approximately a
four-fold reduction, i.e 1600 ISO will look like 400 ISO. For non-camera
images like scans I use Neat Image first, before other operations.

Yep, DxO :-)

Downsizing reduces noise also, see:
"Contrary to conventional wisdom, higher resolution actually compensates for
noise":
http://www.dxomark.com/index.php/eng...-offsets-noise!

Floyd L. Davidson wrote:
"Wilba" wrote:
Following from other discusssions of noise and using tools to reduce it, I'm
interested in when in your process do you do it.

For instance, I can apply NR in ACR, in Photoshop (e.g. Noise Ninja) before
resizing, after resizing but before sharpening, or after sharpening. If you
only did it once, when would you do it? Do you do it more than once, when?

The sooner the better. Noise reduction after sharpening
is absurd, for example. For any process that affects the
entire image, once would be it. But it might very well be
quite reasonable to use a feathered selection to apply more
noise reduction to specific areas of an image.



I do it to a layer over the base, then you can erase the NR layer in
areas that don't need it. Also you can adjust how strong it is easily
and see the effect (toggle on and off). I do this with digital capture
and with film scans. I usually get the levels right, then do the NP
layer thing next is my order. Once I'm happy, flatten and continue
editing. Once is enough.

Stephanie

wrote:
Floyd L. Davidson wrote:
Wilba wrote:

Following from other discusssions of noise and using tools to reduce it,
I'm interested in when in your process do you do it.

For instance, I can apply NR in ACR, in Photoshop (e.g. Noise Ninja)
before resizing, after resizing but before sharpening, or after
sharpening.
If you only did it once, when would you do it? Do you do it more than
once, when?

The sooner the better. Noise reduction after sharpening
is absurd, for example. For any process that affects the
entire image, once would be it. But it might very well be
quite reasonable to use a feathered selection to apply more
noise reduction to specific areas of an image.

I do it to a layer over the base, then you can erase the NR layer in areas
that don't need it. Also you can adjust how strong it is easily and see
the effect (toggle on and off). I do this with digital capture and with
film scans. I usually get the levels right, then do the NP layer thing
next is my order. Once I'm happy, flatten and continue editing. Once is
enough.

This makes sense to me. Stephanie, what tools and methods do you use to "get
the levels right"?

Wilba wrote:
wrote:
Floyd L. Davidson wrote:
Wilba wrote:
Following from other discusssions of noise and using tools to reduce it,
I'm interested in when in your process do you do it.

For instance, I can apply NR in ACR, in Photoshop (e.g. Noise Ninja)
before resizing, after resizing but before sharpening, or after
sharpening.
If you only did it once, when would you do it? Do you do it more than
once, when?
The sooner the better. Noise reduction after sharpening
is absurd, for example. For any process that affects the
entire image, once would be it. But it might very well be
quite reasonable to use a feathered selection to apply more
noise reduction to specific areas of an image.
I do it to a layer over the base, then you can erase the NR layer in areas
that don't need it. Also you can adjust how strong it is easily and see
the effect (toggle on and off). I do this with digital capture and with
film scans. I usually get the levels right, then do the NP layer thing
next is my order. Once I'm happy, flatten and continue editing. Once is
enough.

This makes sense to me. Stephanie, what tools and methods do you use to "get
the levels right"?




I like the levels tool. First I try the lazy approach and hit options
and see what the various choices there look like. Make sure preview is
chosen. The other is to play with the "gray point" and click around on
the image to see if it does something I like. Then move the sliders to
taste. If the adjustment look maybe too strong, you can always edit/fade
this to taste. If you are shooting RAW, it's better to do this in the
development but for jpegs, the level tool is fairly easy to use.

Stephanie

wrote:
Wilba wrote:
wrote:
Floyd L. Davidson wrote:
Wilba wrote:

Following from other discusssions of noise and using tools to reduce
it,
I'm interested in when in your process do you do it.

For instance, I can apply NR in ACR, in Photoshop (e.g. Noise Ninja)
before resizing, after resizing but before sharpening, or after
sharpening.
If you only did it once, when would you do it? Do you do it more than
once, when?

The sooner the better. Noise reduction after sharpening
is absurd, for example. For any process that affects the
entire image, once would be it. But it might very well be
quite reasonable to use a feathered selection to apply more
noise reduction to specific areas of an image.

I do it to a layer over the base, then you can erase the NR layer in
areas that don't need it. Also you can adjust how strong it is easily
and see the effect (toggle on and off). I do this with digital capture
and with film scans. I usually get the levels right, then do the NP
layer thing next is my order. Once I'm happy, flatten and continue
editing. Once is enough.

This makes sense to me. Stephanie, what tools and methods do you use to
"get the levels right"?

I like the levels tool. First I try the lazy approach and hit options and
see what the various choices there look like. Make sure preview is chosen.
The other is to play with the "gray point" and click around on the image
to see if it does something I like. Then move the sliders to taste. If the
adjustment look maybe too strong, you can always edit/fade this to taste.
If you are shooting RAW, it's better to do this in the development but for
jpegs, the level tool is fairly easy to use.

Thanks. Coming from monochrome wet darkroom experience, the black and white
points are very important to me.

Alan Browne wrote in
:

Mostly before re-sizing (but I'd like to hear other opinions).

That makes good sense. There are obvious noise elements removable at
native resolution, like hot and dead, salt and pepper outlier pixels, which
would appear as minor changes in detail after downsizing, to the algorithm.
It is much easier to correct it at the native resolution where it is
obvious what it is (especially if the sensor is oversampling the high-
contrast resolution of the optics).