Q about image processing

C
Posted By
Criag
Oct 9, 2009
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A beginner’s question:
I am trying to learn how to process images taken with Nikon D90 camera. I am wondering what bits/channel mode (8, 16, or 32 ) should be selected for Photoshop CS4.
Please enlighten me. Jorge
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AB
Alan Browne
Oct 9, 2009
James King wrote:
A beginner’s question:
I am trying to learn how to process images taken with Nikon D90 camera. I am wondering what bits/channel mode (8, 16, or 32 ) should be selected for Photoshop CS4.
Please enlighten me. Jorge
If you shot JPG, then 8 bits/channel is fine though 16 bit/channel won’t hurt.

If you shot raw, then 16 bits/channel is right – though if you have extensive editing to do, then 32 bit won’t hurt … otoh, I doubt you’d see the difference.
J
Joel
Oct 11, 2009
"James King" wrote:

A beginner’s question:
I am trying to learn how to process images taken with Nikon D90 camera. I am wondering what bits/channel mode (8, 16, or 32 ) should be selected for Photoshop CS4.
Please enlighten me. Jorge

In general, with a high quality hi-rez image than 8-bit should be more than enough. But if you work on the low-rez, or hi-rez with some damaged color channel, and heavy repairing etc. then you may benefit from 16-bit.

I have only used 16-bit on low-rez photos downloaded from internet, and I only use as DVD Label so they ain’t important for me to try 32-bit to know much about it. But there should be a huge difference between 8-bit and 16-bit
G
gowanoh
Oct 11, 2009
Your monitor and your printer are essentially 8 bit devices with their own gamut or color palette that does not cover the entire range of possible colors. Print gamuts will also vary with paper type. CMYK or offset printing is even more restricted and device dependent.
I don’t recall what the D90 records raw images in but it is 12 or 14 bit color.
When you process images in a wider color space than they will be output to the end result can have unpredictable effects on tones that are at the edges of the gamut that final rendering device can produce. Whether or not this is a real world problem for you only you can answer; it is imaginary for most people. Technically processing some images in 16 bit rather than 8 bit color will generate smoother histograms but if the smoother part of the curve is outside or at the edge of the 8bit final rendering device, which includes the monitor on which the image is being viewed while processed, the question is akin to asking if a tree falls in a forest and no one hears it does it make a sound?
However there is no advantage to processing images above 16 bit color apart from generating massive file sizes that contain only zeroes. If you understand the issues then you may, emphasis on may, be able to achieve more satisfactory results processing raw images in 16 and downconverting to 8 bit for printing and other uses. Many Photoshop plugins and filters will not work in 16 bit color: if Adobe does not make a function available for 16 bit processing then what does Adobe think about 16 bit color?
In the real world most users will find that processing images in 8 bit color is more than sufficient for raw images and yields manageable file sizes. Your choice.
J
Joel
Oct 12, 2009
You have the wrong impression cuz 8-bit, 16-bit, 32-bit etc. has nothing to do with monitor or printer but PIXEL. And it does make a HUGE difference when you modifying heavily.

How to Master Sharpening in Photoshop

Give your photos a professional finish with sharpening in Photoshop. Learn to enhance details, create contrast, and prepare your images for print, web, and social media.

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