Where does noise come from in my workflow?

Bend The Light

I sometimes have problems with noisy images, and I can't quite get to the bottom of it. So, this is what I might do with a typical picture...where might noise be creeping in...where might I be better doing something else?

Shoot at ISO 100 wherever possible, try to have good light.
Copy RAW files into Bridge...sort through good and bad, and delete the bad.
Open an image in Adobe RAW...
Check for burnt out, or blocked up blacks on the histogram...adjust exposure, recovery if burnt out, slight increase in clarity. Tend to leave all other bits alone...
Open image in Photoshop.
May do a curves adjustment (on adjustment layer) if necessary, nothing fancy...S-curve mainly. May adjust saturation (again, on adjustment layer).
Usually add sharpening with unsharp mask, typically radius is around 1 max. Slide up until it looks ok, but not oversharp.
Crop to 10in x 8in x 300ppi.
Save as PSC and then as JPEG, quality 12.

Anyhting in there a problem, you think?
I wonder about cropping...if I crop to 10in x 8in 300ppi, am I adding pixels, or deleting some? If I crop with nothing in the size boxes I will get non-standard crop sizes, but will I then not be extrapolating pixels, or something?

I welcome all ideas to avoid noise in PP.

Thanks

chuckinsocal

My solution would be to check for noise when you first open the image in PS and then check after each adjustment. This should tell you where the noise is creeping in.

Just my nickel's worth. I'm sure there are better answers out there but this is at least a start.

Bend The Light

chuckinsocal wrote: »

My solution would be to check for noise when you first open the image in PS and then check after each adjustment. This should tell you where the noise is creeping in.

Just my nickel's worth. I'm sure there are better answers out there but this is at least a start.

No, that's a good plan.
I know sharpening adds noise, but other than that...I don't know. I will try that...:)

arodney

At low ISO’s, shooting raw without exposing ideally adds some noise:
http://www.digitalphotopro.com/technique/camera-technique/exposing-for-raw.html

After that, proper sharpening that avoids touching darker areas that contain the noise will help too.

pathfinder

Under exposure, corrected in RAW processing will definitely add noise to your image, especially in the lower quarter tones.

How about posting an image for folks to examine and see if your noise seems out of line.

Your workflow, as you described it, seems quite reasonable.

I should mention that even at ISO 100, properly exposed, I can sometimes see noise in my blue skies if I look carefully at 100%. If I find it distracting, I remove it with NoiseWare, or the noise reduction sliders in Lightroom3

malch

As others have suggested, underexposure is the most common cause of excessive noise in low-ISO shots.

The best tool I know of for looking at this is (was) Cryptobola RawAnalyze. This program will basically produce a histogram of the RAW image and give you a true picture of your exposure accuracy. Sadly, I believe the author passed away and I'm not aware of any sites that have the program still available for download.

I have a copy that still works on my D200 NEF's but I'm assuming it will not support the latest (or future) cameras since it's no longer being maintained.

If anyone knows of an alternative/replacement program, please let us know.

colourbox

Bend The Light wrote: »

Open an image in Adobe RAW...
Check for burnt out, or blocked up blacks on the histogram...adjust exposure, recovery if burnt out, slight increase in clarity. Tend to leave all other bits alone...

Do you have to lighten most images? If so, that's a hint you may be consistently underexposing. Lightening raises noise, darkening submerges noise. If you must lighten an image by a noticeable amount, even ISO 100, check the shadows and look at whether you should apply at least a little of the first-class noise reduction in Camera Raw before you move on to Photoshop. Some gurus say even ISO 100 can use Luminance NR of 10.

Really a raw image should not be allowed to leave Camera Raw for Photoshop with unaddressed noise. Because it's easier to deal with in CR than in PS, it should be taken care of in CR when possible.

Bend The Light wrote: »

Open image in Photoshop.
Usually add sharpening with unsharp mask, typically radius is around 1 max. Slide up until it looks ok, but not oversharp.

You might think about adding some sharpening in Camera Raw (after noise reduction) and using the Masking slider to keep the sharpening to the edges only as was suggested in another post. Since sharpening in Camera Raw is much smarter than Photoshop Unsharp Mask.

Bend The Light wrote: »

I wonder about cropping...if I crop to 10in x 8in 300ppi, am I adding pixels, or deleting some? If I crop with nothing in the size boxes I will get non-standard crop sizes, but will I then not be extrapolating pixels, or something?

Cropping never ever adds noise, it only makes existing noise bigger and more visible only if you crop so far that the leftover image is a tiny piece effectively scaled way up. If it's just a little trim, it doesn't matter.

Bend The Light

Wow...some great responses, and some good things to try. I printed this page so I can work through some of the ideas here.

Many thanks to everyone for their input...

Bend The Light

Well, here's an image that people have said is noisy...


jumping spider 1 by http://bendthelight.me.uk, on Flickr

And the RAW is hosted here...

http://www.mediafire.com/file/9cp4epov9sb449y/_MG_8811.CR2

If anyone wants to have a go and process this anyway they like, THEY CAN. Any help in my processing would be appreciated.

basflt

RAW is fine
if you reduce noise , set view to 100 % , so you can see what you do

set JPG quality to 10 , 12 is overdoing

for internet
add a little sharpening after down-sizing
down-sizing dullens a bit

edit
in ACR , check[un]check the preview , so you can compare

Bend The Light

Thanks, Basflt. Will bear those pointers in mind.

Troy Raymond

Sometimes it's easier to just repair as not all noise can be avoided. Since noise is really only noticeable in blurred or out of focus sections I took the photo you posted above and removed all the noise with Noiseware, then pasted it as a layer in photoshop over the original. Using a layer mask I simply used a blurry brush to paint away the noise reduced and show the noisey layer below in only the focused parts.



EDIT: Removing noise in this way will also allow for much larger prints. I have been successful with very detail printed decals of photographs up to 7' using only a 4mp image.

Troy

aj986s

^ IMHO, nicely done!

I believe latest Ligthtroom provides for similar adjustment?

http://davidnaylor.org/blog/2010/03/noise-reduction-in-lightroom-3/

Bend The Light

Troy Raymond wrote: »

Sometimes it's easier to just repair as not all noise can be avoided. Since noise is really only noticeable in blurred or out of focus sections I took the photo you posted above and removed all the noise with Noiseware, then pasted it as a layer in photoshop over the original. Using a layer mask I simply used a blurry brush to paint away the noise reduced and show the noisey layer below in only the focused parts.



EDIT: Removing noise in this way will also allow for much larger prints. I have been successful with very detail printed decals of photographs up to 7' using only a 4mp image.

Troy

Never thought of doing that...but is well within my ability of PS. Thanks.

Troy Raymond

You're Welcome. Just remember to use an appropriate sized brush, I used a brush slightly smaller than the leg diameter so the noise would fade off and made one pass at 100%, Over the eye didn't look right so I painted the noise reduced back in at about 25%. Then really enlarged the brush for the ground that is in focus and made one pass at 100%. This will fade the noisy area over a larger distance making the transition unnoticeable.

A long time ago I started layer blending, I can't remember the last time I even used a selection. Good Luck.

Troy