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I have been working on Photoshop for quite some time now, but there is one thing that has got me confused till now. Is it better to be working on a 16 bit color mode or an 8 bit one? I know that the 16 bit should be better for images etc, as there are more colors to display, but on a file with lots of smart objects , what would be the best mode to work on? Also, does switching from 8 bit to 16 bit change the file size considerably?

I'm not sure whether this is a stupid question! So please be gentle, in case it is!

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It depends on what you do. There are some advantages to 16 bits per channel images, as well as some disadvantages.

Some of the advantages are:

  • If you need to do a lot of color correction/other color based image manipulation you lose less data in transit.
  • If your data source has more than 8 bits of color then you can gain benefit from that.

Some of the disadvantages are:

  • Not all filters work in 16-bit mode
  • You use twice the amount of memory with all problems associated with this.

Basically as a rule of thumb if you do not have any specific reason to use 16 bit color, then you do not need to use it. There's no real advantage for the final image to be 16-bit unless you expect your client to do extensive color manipulation.

  • Thanks a lot!Shall take the comments into recommendation! – Mayank sagar Dec 11 '14 at 12:16
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A friend of mine who is a photographer told me once that he converts his images to 16-bit while editing to reduce a loss of quality. I always wondered if this really had a visible effect, so i tried the following:

I started out with a 8-bit gradient.

enter image description here

In the first image I adjusted the Levels in 8-bit mode. The second image was converted to 16-bit, edited and then converted back to 8-bit.

enter image description here enter image description here

enter image description here

You can see a slight difference with the gradients, but I really don’t know if it would be worth the effort (and the disadvantages joojaa already mentioned) in a real world scenario.

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    For a one-time edit, it's probably not worth it. If you plan on doing extensive editing, it may be worth it, because the sum of the rounding errors will eventually cause significant damage to the image. Consider these two examples: 251.49 * 168.99 (42499.2951) vs 251 * 168 (42168), a difference of 331.2951 (0.78%). If you have 10 filters with a 0.78% loss, you'd have a final image error of over 7%. That can be the difference between photo-realistic and noticeably "Photoshopped." – phyrfox Dec 11 '14 at 16:09
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    When a image is not 16-bit natively, such a conversion can be useful if your filter uses intermediate steps with multiplications or other operations that increase the value of the pixel (in order to avoid overflows), but usually this is more related to the structure used to allocate the data during the calc. – Paolo Gibellini Dec 11 '14 at 16:41
  • This Q&A bubbled up to the top due to a new contribution, but this particular answer would have benefited from adding a similar test with a much smaller gradient value spread: 0-255 is the best possible choice, but real-world gradients have much more noticeable banding since there are far fewer possible values between endpoints. A 16-bit gradient dithered to 8-bit can mitigate visible banding. – Yorik Oct 3 '18 at 18:02
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Simply 16 bit image quality is quite better than 8 bit, because it contain more color that enhance the output Result/image. But the file/image size will be heavier than 8 bit, also it will use more memory (May be hang ur PC if file is large..... Some option may be disable in 16/32 bit. 8 bit is almost OK in every prospect & I will suggest u to not go for 16/32 bit till the time u don't need it.

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So far all these comparisons and examples are really learnable to people that can put in efforts.

In a shift term, Photoshop is smart enough to detect any kind of image that you send to it. However, it depends on the camera megapixel that you use for the image.

The reason why there has been a reduction in the use of the Nikon D40 is that its image quality is as low as an 8bit image and you can't even get a good result from it by trying to manipulate it.

So better Images cf or industrial productions are 16bit and above.

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A 16 bits/channel image is roughly twice the size of an 8 bits/channel image, similar to a CMYK file being 33% larger than an RGB image. What I have not heard in any of the above discussions is the final output device. Although RGB files have a larger color gamut than CMYK files, most printers cannot accurately print the RGB gamut. It is a physical impossibility. Similarly, I would think that any advantages gained in using a 16 bit image would be negated by most printers. If anyone is old enough to remember hi-fi stereo components, think of it as having a turntable with the very best cartridge/needle, but then using crappy speakers. If the final output is intended for multi-media, then perhaps use the 16 bit image, keeping in mind that it is twice as large and will take longer to process.

  • Welcome to GD.SE. I think you're confusing things: The accepted answer already has info on file size, and the difference between CMYK/RGB is irrelevant for this question. – Luciano Jul 6 '16 at 14:10
  • I still use a component stereo system... – Cai Jul 6 '16 at 21:56

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