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I am having an image whose bit depth is 32 bit. So it is possible to create bit depth higher than 24. But is it possible to have image with more than 32 bit depth like 40 or 48 bit depth. Following wiki link say image more than 24 bit depth possible pls tell me is it possible and how can i achieve it? https://en.wikipedia.org/wiki/Color_depth

  • Why would you want a 40 or 48 bit image? – Cai May 31 '16 at 10:23
  • bit per pixel or total pixels. The nomenclature in general changes after 32bits so you start counting again from 8 , 32,16, 8 being ambigious with previous nomenclature. So presumably 40 means rgba 10 bits per channel and 48 means 12 bits rgba or 16 bits per channel rgb, so you see the total bits nomenclature makes little sense so we avoid it. but yes all 4 possibke formats exist. – joojaa May 31 '16 at 14:26
  • Welcome to Graphic Design Stackexchange. We hope your time here is helpful, enjoyable, and interesting. – Stan Jun 1 '16 at 2:36
  • @Cai I am developing android app in that user can upload any image and i want to display it on next page, for this 32 bit depth image my application was failing to load so i did workaround to solve it, but i have to be sure this issue should not occur again. so i need to know for any other bit depth and want to try sample of it. – Bhushan Jun 1 '16 at 5:51
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    The answers cover the concepts, but for a phone application, I am certain that "32 bit depth" means "8 bits per channel plus 8 bit alpha." This is a "regular image" with transparency. Most (all) consumer displays are not capable of rendering a native 32 bit per channel image, and most (all) are optimized for 8bpp. (They may actually resample to something native to the display, but they expect 8bpp) – Yorik Jun 1 '16 at 14:29
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Yes you can. Stan comented the basics but I am explaining more.

Channels

The base idea is that you have one or several channels.

One channel can be for one color, for example Red, Green and Blue, and you can have yet another channel for transparency. (RGB=3 Channels) (RGBA=4Channels)

On a CMYK file you can have 4 base channels and then one aditional so you can have 5 channels.

Bits on each channel

The second aspect is how many diferent values you can have on each one.

The most used is 8 bits, that can have 256 levels for each channel so you can have 8x3=24, or 8x4=32.

But there are other deep, for example Photoshop can use 16 bits on each channel, so you can have a 16x3=48 bit file, plus another 16 for transparencies and so on.

On Photoshop just go to Mode and choose 16 bits.

Diferent file formats and devices

But other devices uses diferent bith depth than 8 or 16, for example a RAW file from a camera can have 10, 12, 14 bit deepth on each RGB channel.

HDRI

There is another file type that do not uses bit depth but a floating point, wich are the HDR files. The High dynamic range images. In theory they have more than 16 bits (which are 65k colors) and in theory can have like 24 bit colors on each channel which are arround 24 millions but does not record them as such.


Edited based on your comment:

User can upload any image...

I think it would be better if you limit yourself to some file formats and some bit depths.

It took YEARS for the browsers to accept 32 bit jpg, because they were CMYK files and inclusive today many aplications display CMYK files WRONG!

This is due CMYK files need conversions based on the embeded color profiles, that involve some matrix calculations, etc.

My recomendation is that you Limit your app to:

  • JPG with RGB information. 24 bits. Remember you can have diferent extensions for the same JPG file.

  • PNG. Here you can have a 8 bit image, 24 bit image and transparency. You need to know what are you displaying below this transparent space... a white screen? Black one? a choosable background?

Focus instead of displaying the colors right and resample it accordingly to your device.

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  • You can have a exr file with full 32 bit float per channel too. Also there are other formats that have higher bit depths though full float is allready overkill for most uses. 24 bits is 16million colors... – joojaa Jun 1 '16 at 19:56
  • Oh, cool to know. 32 bits per channel sounds like a military aplication or astrophisics usage Xo) – Rafael Jun 2 '16 at 14:46
  • Exr is a industry format for filmmakers, 32bit is pretty standard stuff ingfx cards. But yes mostly overkill. – joojaa Jun 2 '16 at 16:04
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Expression of Colour Depth in bits

It's probably an image with 8-bit colour-depth over 4 channels. You would have a 32-bit deep CMYK image with each of the inks, C,M,Y, and K having an 8-bit colour-depth.

4 channels (CMYK) x 8-bit colour-depth = a 32-bit colour-depth image

A 24-bit colour-depth would be an 8-bit colour-depth X the three R,G,B image channels.

3 channels (RGB) x 8-bit colour-depth = a 24-bit colour-depth image

We can get-away with this because as we "mix" the channels we get discreetly different hues.

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