Noise filter settings..C/o Thomasz Major

[Steve Knott]

Dear Thomas

I don't know what happened but I sent you this reply on the 18th june and never heard anymore!

Anyway, firstly, many thanks for your help.. I am sorry I couldnt answer earlier, I was the other side of Australia in Sydney ( Im in perth)!

Anyway.. your advice has been a great help..especially your summary statement! ..

I tried to answer all your concerns, but the message I would really like to convey is - don't mind some noise.

Now onto specifics...


After Ive done the DNP I enter the noise filtration stage and see a default setting.. is that that default setting based on the profile obtained by doing the dnp each time. I ask because it never seems to change, no matter how different my image samples are.

Put another way. even if i just do a rough dnp it still shows default!

Is it actually changing internally, ie defaulting based on the dnp or is it just an arbtrary, for the user to work off?

Even if I dnp a totally different sample from another camera-differnt dpi etc is still comes up with default. am I making my point clear here?

I would enjoy hearing your best method of tackling the noise filtration stage and I have listed 3 approaches I have tried so far . I just cannot decide whats most effective/efficient!

Is it..
1) to reduce the high freq noise level setting, then the middle then the low in turn assessing each preview, or...

2) adjust the y channel in noise levels ( advanced controls) on its own. does this adjustment raise or lower the above high/middle/low noise proportionately?

3) dont touch the noise levels ( leave them at 0 whatever or 'default' and just adjust raise or lower the noise reduction y channel only, or adjust the high/midd/low amounts to taste.

I tried adjsuting the chrominance noise levels beyond the default cr and cb +25% settings but couldnt see any difference?? do you mean for me to lower them into the minus?

In the end is taste and output use, the key end aim here.Is it reallya subjective thing?

I would have thought there was a way of translating the data from the profile viewer in to definitve adjsutments at the noise filtration sstage threefore plotting the profile excaly?

Thanks again Thomas i
I really appreciate your help here. My publisher wants to use my 55mb image for large poster prints, so would you lean more to keeping or smoothing noise-.

I have really been putting all your advice into practise and would like to send you a couple of section examples if possible? Then perhaps we could have a test me versus you on the same image to see who arrives at the 'best 'clean' !! Vlad for example could be the judge!

Lastly I really need to get a scanner myself. I have so many slides to do. Its going to cost a fortune! I have seen scans from a nikon ls4000-high freq noise very evident, have you used one? some referrals would help!

Thanks for your reply

kind regards

Steve Knott
YOUR REPLY TO MY FIRST QUERY WAS:

I don't see any practical use of 'Profile Viewer'.

The device noise profile should be prepared for each film type (combination of manufacturer, film brand and speed). If you shot on one film, you are lucky - you will need just one profile.

The actual filtration process can be controlled on a per-image basis by changing noise filter settings. 100% filtration would usually remove some or significant amount of detail. It is better to leave some noise but preserve details. I usually like to remove completely the high frequency color noise (resulting - I understand - from interference during scanning) and not much beyond this. With your high resolution scans and noise in high frequency, you will be able to make reasonable enlargements without making the noise too visible, but I don't know how much your publisher needs to enlarge them. I often add small amounts of sharpening.

You also have the option of filtering a single picture 2 or more times and combining such filtered images as layers in Photoshop to expose more or less detail and noise as needed at any given area of the image. I use this technique most often for pictures that overall look good when significantly filtered but human hair becomes deformed with filtration as strong as elsewhere on the picture.

I tried to answer all your concerns, but the message I would really like to convey is - don't mind some noise.