A question about noise and enlargements

<p>I've scanned around 2500 Kodachromes at 4000 DPI. I think about 300 or so are suitable for framing and might be worth trying to sell and I would like to prepare them for such.<br>

The majority have some noise is parts of the image so I'm doing my first real experiments with noise removal.<br>

The image here is one of my first experiments using Topaz Denoise 3. It is a 100% crop of and 5296 x 3531 pixel image, comparing the origin noise to the Denoised edit. It's pretty much what the software chose to do only I cranked the noise removal just a little bit more.<br>

I figure the best approach with this particular shot would be to copy the image, Denoise and then mask off the image so that only the sky is having the noise removal.<br>

So here are my questions:<br>

1. As far as the original noise is concerned, how large of an image size would I have to go to before that amount of noise would be quite noticeable at a normal standing distance?<br>

2. Although Denoise obviously removed quite a bit of noise, what's left behind is sort of blurred patterns that are still noticeable. Is this to be expected considering the amount of noise that I'm starting with?<br>

3. If this were your image and you wanted to get it ready for framing or sending to a stock agency, what would be your approach?</p>

<p>Thanks!<br>

<img src="http://img14.imageshack.us/img14/8632/1noisecompare.jpg" alt="" /></p>

<p>Depends on how large the print is going to be and how you're going to print it. If you're printing at 13x15 or smaller - you won't see the noise. If you're printing with an inkjet the dithering routine will break it up and smooth it out even further. If you want to have it printed with a LightJet or Durst Lambda, send a test file at the size you want it printed and see what happens.</p>

<p>You might also want to look at the image as a single channel (blue which is the noisest channel) and run the noise software again only on that channel. I've also used PS "Despeckel" only on the blue channel. That acts like a median filter and reduces the noise a different way.</p>

<p>Thank you Steve.</p>

<p>DeNoise leaves a very particular squiggly pattern in some circumstances that does show up in enlargements. Try viewing your file at 100% to see if it exists and if it is acceptable to you.</p>

<p>Thanks John.</p>

<p>To prepare a photography, i work with 16bits until colour hue saturation ,etc is ready, then, in 8bits I use Genuine Fractals to enlarge, then I give some noise with Realgrain to make the textures more natural, and thats it. I have enlarged until 59 inches (wide measurement in a 35mm) with a nice looking. What can also help is to choose a good paper (ilfochrome) and a good printer (lambda).<br>

Hope that helps.</p>