Why are .TIFF files so large?

[August 15 Photography]

I was just curious, I have never really thought about it until recently, but if your RAW image out of the camera is lets say 6MB why when you make your adjustments and then save in .TIFF is it sometimes twice the size or larger?? Not that its a big deal, Im just curious.

[Jim G]

RAW files have some form of lossless compression, iirc... TIFF files are uncompressed.

[00silvergt]

Raw is a proprietary version of Tiff. Tiffs are uncompressed images. You are introducing data to the image when you edit it in PS or whatever, uncompressed it may be doubling in size.

[Epix]

I was just curious, I have never really thought about it until recently, but if your RAW image out of the camera is lets say 6MB why when you make your adjustments and then save in .TIFF is it sometimes twice the size or larger?? Not that its a big deal, Im just curious.RAW files are typically 12-bits per channel and TIFFs are 24-bit per channel.

[August 15 Photography]

Makes sense. Thanks all.

[RandyMN]

I've noticed that sometimes my TIFF's get four times larger than the original RAW. I've had a CD of 20 MB TIFF files but I think it's because I made them at 300 dpi.

[cadred]

RAW files are typically 12-bits per channel and TIFFs are 24-bit per channel.

I don't think that's quite accurate. Tif/Tiff files can support a variety of bitdepths up to 32bpp CMYK or 24bpp RGB, but can be less (such as 8bpp). Tiff files can also be compressed via LZW lossless compression, though some image readers might not support that (like my HP printer).

As far as I'm aware there is no actual "RAW" format (Adobe is trying with their DNG format), that's just a generic term to call whatever unprocessed sensor data a camera can produce. Each camera company has their own proprietary format to deliver this (hence the many updates to ACR and the like as the add more formats).

So that means there is no standard compression technique or bitdepth, though 12bpp is most common and newer cameras are getting to 14bpp, and I suspect in a few years we'll see true 16bpp sensor data.

Process raw files are often converted to a 16bpp Tiff file because it is the most standard non-proprietary format that supports more than 8bpp (as your average jpg does). There is no standard 12bpp Tiff format, so it uses the next best thing - 16bpp. That extra data is unused, which contributes to the larger file size compared to RAW files.

So wasted bitdepth + uncompressed Tiff's = larger file size.

[00silvergt]

I don't think that's quite accurate. Tif/Tiff files can support a variety of bitdepths up to 32bpp CMYK or 24bpp RGB, but can be less (such as 8bpp). Tiff files can also be compressed via LZW lossless compression, though some image readers might not support that (like my HP printer).

As far as I'm aware there is no actual "RAW" format (Adobe is trying with their DNG format), that's just a generic term to call whatever unprocessed sensor data a camera can produce. Each camera company has their own proprietary format to deliver this (hence the many updates to ACR and the like as the add more formats).

So that means there is no standard compression technique or bitdepth, though 12bpp is most common and newer cameras are getting to 14bpp, and I suspect in a few years we'll see true 16bpp sensor data.

Process raw files are often converted to a 16bpp Tiff file because it is the most standard non-proprietary format that supports more than 8bpp (as your average jpg does). There is no standard 12bpp Tiff format, so it uses the next best thing - 16bpp. That extra data is unused, which contributes to the larger file size compared to RAW files.

So wasted bitdepth + uncompressed Tiff's = larger file size.

Exactly. Raw is uncompressed or unprocessed (with the exception of Sony's) format. But more accurately, uncompressed.

[Bodog]

You're missing the real reason RAW files are smaller. They simply contain less information. Tiff's are image files with full RGB color information for each pixel, whether it be 8, 16 or 32 bit. RAW files have no color information, only a luminance value for each photo sensor.