How can i make Photoshop open 24 bit tif files as 16 bit images? I've checked the CameraRAW settings and it is set to 16 bit?
I'm opening a series of tif files in a stack just for context but it happens even whenb i open them individually.
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I should add that they currently open as 8 bit images?
24 bits = 8 bits x 3.
Just different notation, total or per channel.
I'm not sure i understand correctly?
Photoshop used to show the images as 16 bit (The images are renders) and when using some of the blend modes they behaved in a way that worked. Now they behave like 8 bit images, especially on colourdodge, so i really don't thik Photoshop is seeing them as 16 bit?
Yes, to get a 16 bit per channel TIFF file, it would be called a 48bit TIFF per your terminology. https://helpx.adobe.com/uk/photoshop/using/bit-depth.html
What do you mean about Color Dodge, the result of the blending mode should be the same.
The only difference might be, when you look at it at lower magnifications, the image pyramid of 16bits was sometimes converted to 8 bits, prior to the August 2022 version: https://helpx.adobe.com/uk/photoshop/using/whats-new/2022-4.html
The rule of thumb: only compare images at 100% magnification.
That's really useful, thank you.
The colour dodge blend mode is something i use for bloom and glare, but the way it behaves now doesn't seem to be the way it behaved a while ago, especially at the fringes of a bloom effect. You now get this weird rainbow banding effect, which i didn't used to get when photoshop worked the images as 16 bit mode.
And to clarify when i specify the output of the tif files for rendering i'm specifiying 16 bit, but when i look at the properties of the image through windows it says 24 bit.
This is simple: you're working with 8 bit files, hence the banding.
You can convert to 16 bit in Image > Image Mode. This won't do anything to the existing data in the file - but it will provide additional headroom in further adjustments. So you should avoid the banding after conversion.
Keep in mind that your original data, even as 16 bit, is still stepped in 8 bit increments. To get the best results, convert to 16 bits as early as possible.
But if photoshop has opened them up as 8 bit, won't that lose the 16 bit information in those images and therefore moving the bit rate up to 16 bit would be useless no?