Converting TIFF to DNG

The DNG converter only converts raw files to the DNG format. It never has converted TIF images to DNG. Since you only have Photoshop CS2 I don't see any way for you to make the conversion to DNG.

Hi everybody, I have this TIFF to DNG issue too.

Actually, I have a negative scanner which gives me 22 Mega-pixels, 48-bits TIFFs. I've scanned a lot of old negatives and I'd like to process those "now-digital" negatives with the same workflow than my "genuine digital" camera raw files (correcting chromatic aberration, vignetting and all the usual whitebalance, exposure, etc. stuff). Please note that I have access to Photoshop CS2, not CS3, and the latest Camera Raw plug-in supported by CS2 is version 3.7, which
doesn't support TIFF files as input. It does support DNG though.

So, does that sound now like a good reason to convert TIFF to DNG?

That should be easily done, but even Adobe Digital Negative converter 4.5 won't use TIFF as input files.

I'd just like to do that (dumb) conversion without buying additional software (or I'll have to code it myself with the DNG specification... don't have that time right now). Any ideas?

Thanks for that Eric, I had a feeling that might be the case but talked myself out of it. Surely this capability is as relevant to JPEGs as it is to RAWs and not so difficult to implement. One for the wishlist to go to Adobe perhaps?

When using just Adobe products, there is not a strong workflow reason to convert JPEG/TIFF files to DNG. The workflow benefits mostly come in mixed company workflows where you take advantage of the embedded previews possible in a DNG file. This would allow to make "non-destructive" changes to the underlying JPEG/TIFF data, and render previews to embed in the DNG so non-Adobe software (e.g. a third party DAM) can see the adjusted preview images.

The big downside of converting JPEG files to DNG is the size increase due to the lack of a lossy compression option in DNG for the main image data. This is not an issue of TIFF files converted to DNG since the lossless compression in DNG is actually quite good, and can sometimes result in the DNG file being smaller than source TIFF file despite the embedded previews.

>BTW, it was my understanding that some future rev of DNG was going to be tweaked
a bit to handle tiffs and jpegs better. Any insight?

You mean a future rev of Camera Raw? I can't comment on thatother than to say that even Camera Raw 4.5 now has it's own virtual memory and can open a 512MP imagewell beyond the old limit of 10,000 pixels.

Thank you for setting me straight, Jeff. I have used ACR to edit JPEG images frequently, but had never considered that there was any value to saving them as DNG files. I will have to go back and give that a try on some of them.

>As far as I'm concerned, there is no logical reason to convert a JPEG or a TIF image to the DNG format.

Actually there are both workflow and technical reasons to do so. You want to adjust hundreds of JPEG images quickly and easy? Open in Camera Raw, adjust the images and resave them as JPEG, TIFF or PSD. A lot quicker than doing so one by one in Photoshop.

Technically, doing substantial adjustments to JPEGs (in particular) in Camera Raw will result in better final images than doing so adjustment by adjustment in Photoshop. You'll get less rounding errors and the final resultant image will be smoother doing the same thing in Photoshop with less chance of banding.

Look, there are two flavors of DNG...one where the data is un-demosiaced and one that is. The fact that Camera Raw (and Lightroom) can edit both flavors is actually a plus. Yes, it might be useful for have some indicator whether a DNG is raw or linear....but for the purpose of Camera Raw and Lightroom, both are treated the same with the raw file having far more flexibility in processing. But don't dismiss the usefulness of working on non-raw files as DNG.

As far as I'm concerned, there is no logical reason to convert a JPEG or a TIF image to the DNG format. Some people seem to think that by doing this while they are creating a raw file. But that simply is not the case. The image has already been preprocessed in the camera, it has been demosaiced, and in the case of a JPEG image in particular it is an 8-bit image. Converting it to DNG is not going to magically change it to a higher bit image and create all the extra image data.

Even for the purposes of a smooth workflow it doesn't make sense to me. It isn't the same kind of image file, and it seems to me that it would probably have to be handled differently in editing in Photoshop. But if, for some reason, you feel you are defying reality and are creating some magical image by doing the conversion, have fun. It just doesn't make sense to me.

The JPEG image never did contain the white balance information that is stored in a raw image. It only contains the embedded profile, and that is all that can be included in the DNG conversion. As I've said before, DNG files created from JPEG or TIFF images are different. They don't contain all the metadata.