RAW conversion issue

[Patrick Gauthier]

Hi LFF!

I shoot 4x5 B&W and by various means scan my negatives and post-process with lightroom/photoshop. My scans are RAW files and are quite large (~170 mp). About 99% of the time I can convert these while still preserving the digital editing I have done. However, when I have a particular dark and contrasty scene (especially a lot of micro contrast), the conversion cannot handle the dark tones and I'm left with something 'blander' than the RAW file.

Does anyone else work with RAW scans and encounter similar issues? Are my expectations too high?

LEFT IMAGE: lightroom develop module (RAW)
RIGHT IMAGE: Exported jpeg 100% quality in photoproRGB

You can clearly see the differences in the shadows and blacks on the rockwall. The difference is more striking on actual quality files.



Patrick

[Kirk Gittings]

I can't really see the difference on my laptop, which is all I have with me. I have been printing B&W for over ten years now from scanned negs and always work with just Tiffs or the large file PS format. I have never felt that I lost anything by not working in raw format even though I push and pull the tones all over the place.

[Peter De Smidt]

Is this really a raw file, like a file from a Nikon or Canon dslr? I doubt that is the case. By chance, is it from Vuescan? My understanding is these are simply tiffs that save all of the non-software adjustments so that they can be reprocessed by vuescan down the road. Moving on to your color space, do you mean prophotoRGB? If so, why are you using such a huge color space for a black and white image?

[Patrick Gauthier]

Hi Kirk,

A rare situation where working with RAW files may be worse. You may have led me to a solution: exporting un-processed RAW files as .tiff and then directly post-processing the .tiff. With the current image, I may be able to just save the processing adjustments and quickly apply them to the .tiff.

I also occasionally handle .tiff files for processing, this happens when my scans exceed the maximum file size for the photoshop raw .psd format, but typically prefer to work with the raw files because of a speedier workflow.

I will re-post when I try the direct .tiff editing on this particular image tomorrow.

Thanks!

Patrick

[Kirk Gittings]

IME A raw format for raw conversion only offers some benefit when the b&w image is a conversion from a color original. Otherwise the quality of a the scan is a much more important factor such as a drum scan vs. a consumer flatbed.

[maxotics]

Keep in mind you can't really view a RAW file. It has 12 to 14-bits at each pixel location (RGB) and your monitor can show only 8-bits. So somewhere blacks must be pegged to start in an 8-bit space otherwise the RAW would just average to gray (which is how RAW video looks). Or put another way, I don't think it's a problem with your RAW file, it's how your Lightroom Develop module is configured to interpolate the large dataspace of your image down to something your monitor can display and you can see. You can't really look at RAW, sort of like you can't see infra-red.

A good test for you to do is to open the RAW file in the RAW filter and adjust it to your liking, then save as JPEG, then do the same to the JPEG. If there is not difference, use JPEG. If you can get a better tonality with RAW, keep using raw.

[Patrick Gauthier]

Hi Peter

Is this really a raw file, like a file from a Nikon or Canon dslr? I doubt that is the case.

Yes they are true raw, I scan and stitch with a mirrorless camera (sony nex).

Moving on to your color space, do you mean prophotoRGB? If so, why are you using such a huge color space for a black and white image?

I only have three options in exporting from lightroom/photoshop, I normally export with sRGB, but tried prophotoRGB to see if it was any better.

[Lachlan 717]

Given there is no specific ".raw" format (it's a grouped nomenclature of many sub formats), perhaps you are using an unrecognised or partially recognised sub-format.

Why not just use .tiff with properly scanned (unclipped) settings? Given it's lossless/uncompressed, you won't be losing data.

[Christopher Barrett]

Ahh... I think you were causing some confusion by saying RAW scans. You can't get raw files from scanners. Even the Hasselblad .FFFs are actually tifs. Now, digital captures... that's a whole other ball game. Have you tried using Capture One Pro? I use it exclusively for my commercial workflow and greatly prefer the file quality versus Lightroom.

Like Kirk, I don't really see any shadow detail difference in your screen captures, but I'll take your word for it. I'm not sure why you're working with Jpegs, though. Even at 100%, they're still compressed files, so I'm not surprised at all that the algorithm is throwing out shadow detail.

Lastly, I've never had much success "scanning" negs with a digital camera, and this was using a 60megapixel Phase One back... well at least when compared to my drum scanner. But if you're seeing what you want in the RAWS, there is absolutely no reason you can't output that to a 16bit Tiff, which is what I would print from.

IMHO,
CB

[Peter De Smidt]

Hi Peter

Yes they are true raw, I scan and stitch with a mirrorless camera (sony nex).
I only have three options in exporting from lightroom/photoshop, I normally export with sRGB, but tried prophotoRGB to see if it was any better.

Ok. So you get the image how you like it in Lightroom, but when it's exported to Photoshop it's changed? Is that right?

Pro Photo RGB is a huge color space. About 13% of it's colors are imaginary colors that aren't visible. It's a great space if your image has some really saturated colors, but a bw photo doesn't have any. Pro Photo RGB's gamma is also 1.8, unlike sRGB's and Adobe 1998's 2.2. Either of those would be a better choice for your output space.

Speaking of color spaces, what's your working/editing color space in Photoshop? If there are some conversions between spaces happening they could cause a visual difference in the image.