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-   -   File sizes and bit depth (https://forums.steves-digicams.com/general-discussion-11/file-sizes-bit-depth-25525/)

mdparker May 13, 2004 10:07 PM

Playing around with Raw some more now that I have my Nikon Capture software and I must say I really like Raw. I find it much easier to manipulate my raw shots. I want to make backups of my raw files in another file format and I'm trying to figure out the best file type for this purpose. The problem I'm running into is some of the file types are so big. For instance, 16 bit tiff is around 35MB / pic. When exporting my shots I can do 8 or 16 bit Tiff or jpeg (is it 8 bit? ) I sort of understand the difference between 8 and 16, but not 100%. When would I want to use one or the other? For backup purposes is an export to jpeg good enough or should I use tiff? I understand that tiff is lossless and jpg is lossy, but coming from raw, am I going to notice enough difference to justify the larger file sizes of tiff (even 8bit tiffis about 17 to 18 MB ... that adds up)

Thanks for your help.

eric s May 13, 2004 11:47 PM

The standard TIFF format is not compressed at all. You should look into seeing if the TIFF you're using is or is not compressed. TIFF supports multiple compression formats (including the lossy jpg compression.) So you might try the lzw compression setting to see how small the files will be.

Many things won't benefit from the extra data that 16-bit color will provide. But some pictures will. It has to do with how many colors and shades you have in the picture. It also depends on how much post processing you think you'll do. The more you process the picture, the more data per pixel you really want. It depends on what type of processing, of course. There is no hard and fast rule, though. Sorry.

Eric

mdparker May 14, 2004 9:32 AM

Thanks for the reply Eric. I wish there was a hard and fast rule, but I undertand. I hadn't thought about using lossless compression with Tiff, so I'll have to try that. I don't plan to do much post processing on most of my pics and when I print them, it is from jpg, which is 8bit isn't it? So it sounds like I ought to be fine with 8bit for the majority and perhaps even jpg if I don't plan to edit further ... and of course I'll always have my raws as long as I can find software to read it.

JerryF May 14, 2004 10:08 AM

I was looking at my jpeg pics from my Fuji FinePix and they contain 24 bit depth.

I'm surprised that your RAW files get saved as 16 bit depth.

slipe May 14, 2004 10:38 AM


If by backup you are referring to archiving I would archive them in raw. It is the most efficient way to archive the images and has the most information.

If you want to back up an image you have worked on I would suggest the proprietary format for your image editor so you save the layers. But also save the original raw image.

JerryF wrote:
Quote:

I was looking at my jpeg pics from my Fuji FinePix and they contain 24 bit depth.

I'm surprised that your RAW files get saved as 16 bit depth.

There are two ways to refer to bit depth. Photoshop uses the depth for a single color. Raw does as well. There are 3 colors to a pixel, so 8 bit is the same as 24 bit and 16 bit is 48 bit when expressed in 3 colors. So your Fuji files will show as 8 bit in Photoshop.

mdparker May 14, 2004 10:44 AM

I could be wrong, wouldn't be the first time, but I think the 24 bit you see is for all 3 channels. Our pictures have a red, blue, and green channel (I think that's the colors) that are combined in various amounts to make all the colors we see. So on your jpg, if each channel is 8 bit x 3 channels, you have a total of 24 bit picture. On my tiff's, I could go 16 bit per channel x 3 for a total of a 48 bit file.


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