32bit images as textures
Chris Fox Art
Posts: 380
Just wondering if there is a way to use 32 bit images in carrara.
The only file format that is available in carrara that can also use 32 bit is the tiff format, i can add them in the shader room but on 32bit textures there is always an error while 16bit works fine.
Using 32bit tiff format in a carrara scene works only if i import the full scene to octane standalone but there i can use any 32bit image, dds, exr, hdr, tiff, and so on.
The question why i ask about using 32bit images is just because i'm curious of the differences from 8bit to 16 bit to 32 bit, there is a little color improvement on the 16bit image compared to the 8bit regular images but 32bit is a lot more color than 8 bit.
Anybody else have experienced with different bit-sized images?
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Comments
I think you might send this to Daz support. It appears the 16-bit import is actually getting sampled to 8-bits.
There's little point in using 32bit "texture maps",. if you're not rendering out to a 32 bit image.
Carrara can use 32 bit HDRI for scene background and lighting,. other than that it's not going to benefit you to make 32 bit versions of texture maps. infact it would be a problem since the memory required to load those would be much more than needed, and provide the same visual results (depending on what bit depth you export at).
32 bit is much more useful in post production, with 32bit,. you have a greater degree of control/adjustment available, because there's more information.
As far as "Support" for carrara issues/bugs/updates is concerned,. ..that's over..
don't expect anyone to fix anything in carrara.
Support might be able answer to something not covered in the manual or docs. It does not have to be a bug. Of course asking here might get get an answer as well.
i was toying with the tif option as well.
when saving a car file "externally" option, it saves out tif files. thinking might as well start out with tif files
how do you figure out how many bits are those externally saved tif files?
In Windows, Right click the image and get Properties, go to Details tab and check down in the list. Some image formats, like Photoshop PSD may not display this info.
ty
misty wrote
I think that the TIFF format for internal /external saving shows the age of carrara,. (Pre PNG) tiff was probably the best format at the time carrara was built. and was never changed.
PNG is 8 and 16 bit and has alpha (same as tiff) but is a much smaller file format.
16bit tiff file is about 90 - 100MB in size, 32bit size is about 190 - 200MB in size.
The same 32bit file as exr is about 16MB
@Philemo: So i open the 4000x4000 32bit file in photoshop, resize it to 8000x8000, change the mode from 32bit to 8bit and in carrara i will have the same results like the 32bit image from the 8bit image?
Just to be sure i've got this right.
By the way, open a picture in photoshop, click on picture, than on mode and you see if 8bit is selected or 16 bit or 32 bit.
What i found pretty interesting is that from 8 to 16 bit in carrara with octane shaders and octane renderer there is a bit more color, saving the file as ocs file and open it in octane standalone, the shader settings seem to be a bit different as the textures gets a lot darker.
The first, darker picture is rendered in octane standalone with 32bit textures and same settings i have in carrara, the second one is 16 bit image in carrara octane renderer.
You can change the gamma in your photo editing app. This might give you the desired result.
Gamma might be called something different in your photo editing app. Basically it allows you to adjust the proportion of light to dark. Its not the same as brightness/contrast.
Yes, if you consider that precision is important in the change of colour. For a flat colour, it won't help, the result will be the same as not resizing. But, when resizing, the algorithm should interpolate the new pixels from the neighborhood. So, if there is a variation between close pixels, it will reflect in the new ones. When Carrara will compute the colour for a particular point, it will sample four times the number of pixels, averaging the value.Carrara renderer internally uses floating point values, so averaging should not loose too much precision.
I was also wondering if it would be possible to write an import filter for, for instance, exr 32 bits files. Carrara can store 32 bits internally but I don't know if it will be transformed in 8 bits values at some point before being converted to floating point. If so, it's a waste of time. If not, it could be easily done
Ground Control allows import of 16-bit greyscale. Perhaps Eric knows if its possible for high color RGB.
is there a trick for minimizing banding on a color gradient bg?
I experimented with this (using Photoshop) .... adding noise helps especially if the color mode is changed to 16-bits/channel before adding the noise. (I did not try it with 32-bit)
Then change color mode back to 8-bits/ch and use Diffuse filter. I did try diffuse as a 16-bits/ch image but in my opinion it did not smoothen as much after converting the image back to 8 bits/ch as it did in appying it directly to the 8-bits/ch image. In some cases Diffuse did not improve the appearance.
I think compositing or masking might be needed to ensure only the banding is affected.