Noise With My Slide Scans

[Charles Wesley]

Please help me with this scanned closeup image of a dandelion. I used my Epson Perfection 4990 Photo Scanner. The sittings were 42 bit color and a resolution of 3200 dpi. I processed with PS/CS4 as follows: duplicate layer, levels, curves and contrast. I then used Neat Image to remove noise from the blue cloth BG. Then I went back into PS and used FocalBlade a sharpening plugin after using my Waucom tablet to only select part of the bloom and seeds in the dandelion.

When viewed at 200 %, I still see some noise and the UR BG area has a funny look to it. This photo was taken with a Nikon F5, Nikkor 200 f/4.0 macro lens, SB 24 flash set at low power with window side lighting. The slide is properly exposed.

Any ideas in how to improve the BG would be greatly appreciated. Am I seeing redidual noise or jpg compression artifacts?
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Charlie Wesley
St. Augustine Beach, FL

[Roger Clark]

Charlie,
I think I see what you mean. It looks a little darker and slightly different color. You might try looking at the individual red, green and blue channels to see which color is off, then select it and try and correct it, e.g. with curves or levels. The challenge will be feathering the selection so that it matches the change region. You may need some cloning and/or blur to fix the transition region. Because it is already a small effect, only a small change is needed to fix it. Please let us know if this works.

Roger

[Charles Wesley]

Rodger,

Thanks for the advise. I will work on it tomorrow. It has me a little ticked right now.
I guess I need to play with it if I get what you're saying...
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Charlie Wesley
St. Augustine Beach, FL

[Dan Brown]

Just a thought and a question, what if you rescan and set the scanner exposure higher? This might simulate a "exposed to the right" histogram, which may produce less noise?

[Charles Wesley]

Dan,

That's a great idea. Never thought of it. It makes since that the image should be less noisy. I'll definitely try it...
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Charlie Wesley
St Augustine Beach, FL

[Roger Clark]

Charlie,
It will be interesting to see if a rescan will help. I have a 4990 too and it is a pretty good scanner, relatively speaking, though not a good as a dedicated 35mm film scanner. I use mine for 4x5 film. My impression is that the noise is pretty good with the scanner and the dominant noise I see in my images is due to film grain (I shoot velvia; actually used to shoot velvia--haven't done so in a couple of years.)

Part of the noise perception you see may be due to the level and changing the brightness may improve the perception and show less noise. So it will be interesting to see if a rescan helps more than simply brightening the corner region.

Roger

[Charles Wesley]

Rodger & Dan,

Thanks for the advice. I can't seem to make the corrections work. Definitely found more noise on the red channel. When I tried to use the healing brush tool there is strange little artifacts everywhere. I can't select a good blue color. A curves or levels adjustment doesn't help.

Am working on a rescan with a higher exposure. Hey I thought with my training and knowledge I could improve this image...
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Charlie Wesley
St. Augustine Beach, FL

[Charles Wesley]

Rodger & Dan,

Think I found a way to get better scans. Still can't find the dandelion slide to redo. Histogram adjustment doesn't work as well. No idea why. Now I check preview and do an auto exposure correction or tone/curves adjustment. Find I can make other corrections in PS/CS4.
Posted another image using new technique...
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Charlie Wesley
St. Augustine Beach, FL

[James Shadle]

Do you have an over-sample option?

[Charles Wesley]

James,

I don't know but will check it out. Thanks for the help...
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Charlie Wesley
St Augustine Beach, FL

[Roger Clark]

Charlie,
You might also try output as 16-bit files (e.g. tiff). That will give finer gradations in tonality.

Roger

[John Chardine]

Just another thought but I can't see where you mention what film you used. Are the scans simply capturing the graininess in the film?

[Charles Wesley]

John,

You may be right about the grain. My second slide in this tread was done with a lower resolution of 2400 vs 3200 dpi. My films so far, only used the scanner for 2 weeks, are Fuji Velvia, Kodachrome 64 and Ektachrome 100.

Thanks for your help...
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Charlie Wesley
St. Augustine Beach, FL

[john jackson]

Hi Charles

Your dragonfly image is gorgeous.

A question: why would you want to look at an image at 200%? Doesn't any image look bad at such magnification?

[Charles Wesley]

John,

Thanks for your kind comments. I check all my images at 200% now after hearing critiques from certain pixel peepers. Totally agree with your logic. Wish everyone did...
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Charlie Wesley
St. Augustine Beach, FL

[Charles Wesley]

Doing better with my Epson 4990 Expression Photo Scanner. Not using the histogram adjustment as much and getting better results. Seems the tone / curve adjustments works better than levels with the provided Epson Scan software.
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Charlie Wesley
St. Augustine Beach, FL