From RAW to 16bit TIFF ... Compress or not?

[phildog33]

From RAW... convert in final stage of Adobe Lightroom to 16bit TIFF and prepare for EXPORT.

IT gives the options for:

1. None
2. Compress via ZIP
3. Compress via LZW

Whats the consensus here...?

Everybody (seems like 100%) here advocate keeping your RAW files in 16bit mode.
Im interested who on the forum is downsampling to 8bits on purpose.

But i havent seen a thread about the compression of those TIFFs... LZW and ZIP save about 1/2 the file size. Is it worth it to compress and keep that TIFF as archive quality?

Thanks
-p

[phildog33]

and also to ask... about the option of saving in ProPhotoRGB instead of AdobeRGB.

[Dustbak]

I do not safe the Tiff files that would be too much storage. I do safe the RAW file.

When compressing you are best of using LZW, this compression is understood by most programs (more than ZIP for images).

No need to keep the file converted to ProPhotoRGB either that way.

Yes, I do need a copy of LC in the future when I want to extract the most out of my RAW files. But.. my problems are much bigger than that. How do you keep TBytes of data in good health over a longer period of time in the first place? Anyway that is a different discussion.

[Jonathan Wienke]

The TIFF compression is lossless, so your choice should be based on greatest compatibility with other applications. Save a file as both LZW and ZIP compressed and see if any of your programs have difficult opening one or the other.

Contrary to dustbak's advice, there is no good reason to change the color space from ProPhoto. The only time you should change color space is when converting and optimizing an image file for a specific output device such as a printer, and that should always be done on a separate copy of the file, leaving the master copy untouched. Most digital cameras are capable of recording at least some colors outside Adobe RGB when shooting RAW, so ProPhoto is the best option for your working/editing color space. It gives you control over how highly saturated colors get fitted into smaller-gamut spaces.

[Dustbak]

Euh Jonathan,

I think you misunderstood me. I meant there is no need to change to another color space, I just keep the RAW with the color space attached to it instead of saving it as a TIFF/PSD. This way you will also not get to the question of whether to convert the color space to ProPhotoRGB when you have it captured in AdobeRGB in the RAW file. I just leave it as is and only convert when needed for a specific output.

basically exactly what you are saying here.


Maybe I expressed myself a bit crippled

[rainer_v]

lzw compression sometimes enlarges 16bit files, which means it does not work with 16bit files.

[phildog33]

a little confused...

is this the consensus:

1. raw
2. export as 16bit TIFF
3. with ProPhoto RGB
4. save all RAWs and save all processed TIFFs with ZIP or LZW compression???

-p

[Dustbak]

I think the consensus here is:

1) Shoot in RAW (are there other options with MFDB's?) in ProPhotoRGB (just to get the widest color space in the first place).
2) No need to convert to another colorspace when it is not necessary, only convert for specific output.

We differ on:

1) Whether to save Tiff as well. I do not but others apparently do. I would have over 4TB of storage by now when having saved everything in Tiff.
2) I would choose LZW compression since that is most widely used and least likely to create problems (testing before using would be wise here). According to Rehniar this sometimes enlarges files (like zipping .mpg videofiles) making it a rather futile action.

It is not a real best practice issue but more an issue of personal preference.

[Cfranson]

2) I would choose LZW compression since that is most widely used and least likely to create problems (testing before using would be wise here). According to Rehniar this sometimes enlarges files (like zipping .mpg videofiles) making it a rather futile action.

Yes, as mentioned above, LZW compression of 16-bit TIFF files does not work.

[John Sheehy]

This way you will also not get to the question of whether to convert the color space to ProPhotoRGB when you have it captured in AdobeRGB in the RAW file.[a href=\"index.php?act=findpost&pid=96947\"][{POST_SNAPBACK}][/a]

The RAW file only has a tag that says to use AdobeRGB upon conversion, and the embedded JPEG is in AdobeRGB.  The RAW data itself is in the unique color space of the sensor and its filters; three interleaved greyscale captures, each with a different color filter.

[Ray]

If you don't mind sacrificing your layers (ie. flattening them) you can use the lossless PNG format to compress 16 bit images. Files sizes seem to be about 2/3rds. Color profiles are preserved.

[Jonathan Wienke]

I think you misunderstood me. I meant there is no need to change to another color space, I just keep the RAW with the color space attached to it instead of saving it as a TIFF/PSD. This way you will also not get to the question of whether to convert the color space to ProPhotoRGB when you have it captured in AdobeRGB in the RAW file. I just leave it as is and only convert when needed for a specific output.

RAW files are all in their own color space unique to the camera that captured them. No RAW file is Adobe RGB or ProPhoto, the color space is unique to the sensor and ISO setting. Part of the RAW conversion process is converting the Bayer-interpolated RGB data from the camera-specific color space to a standard editing space like ProPhoto, using some kind of camera profile to control the start of the conversion. ACR uses adjustable (via the calibration tab) internal camera profiles, Capture One and other RAW converters use fixed ICC camera profiles.

RAWs can be tagged with a recommendation to use a particular destination editing space, but you are completely free to ignore the tag's recommendation and convert to whatever space you choose.

I archive all RAWs (minus severely over/underexposed. out-of-focus, etc. which I delete) and save processed images (<10% of all images, client selects and otherwise "keepers") as Photoshop PSD, in ProPhoto. I have close to 2TB of stuff right now.