Author Topic: Hasselblad RGB and L*  (Read 758 times)

Offline Brad Paulson

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Re: Hasselblad RGB and L*
« Reply #15 on: January 07, 2018, 09:36:11 PM »
I’ve been exporting TIFFs with embedded 16 bit H RGB and L* ICC profiles by setting up a custom export preset in the export dialogue box.  To use L*, it appears that you have select L* as your working space in Phocus (under Reproduction), and set the custom export dialogue to use the “source” working space.  Be sure to select the 16 bit TIFF export if you do this, not the 8 bit which is too small for that large of a workspace.  During the last few days, I’ve used these files successfully in Photoshop and surprisingly all PS plugins I’ve used to date too.  I imagine it would work in LR, though I’ve stopped using LR now, if you are willing to work there with TIFFs.

Now that I located the L* ICC profile, I also created a printer ICC profile during the last few days (one needs a spectrocolorimeter and software to do that) that translates the L* colorspace directly to the printer colorspace.  If you make one, you can use the printer ICC profile to accurately soft proof your printer/paper combo.  Seems to work very well so far.  The L* space is huge, like ProPhoto, which isn’t necessarily great when downsampling those gamuts into narrower printer colorspaces. So finally I’m working with ArgyllCMS to create custom image gamuts based on the image’s specific gamut and mapping that image’s gamut directly to the printer.   This latter step of making custom image gamuts is completely impractical if you make large prints, have only a moderately powerful computer, and wish to produce more than a few new pictures a day, and there is a steep learning curve.  The processing times for large files meter long images can take a while and make you think you've been transported back to the 1980s.  But I’m learning it anyway. 

The nice thing about this workflow is it should avoid any image clipping that might otherwise occur when converting to the more common Adobe RGB or ProPhoto RGB workspaces, any other color mapping degradation in the conversion process, and you can continue to work in the gamut that was used initially to process the raw file.  It’s too soon to tell if it makes much of a practical difference, but theoretically it seems likely it will. 

I would really like to learn more about Hasselblad L* – if anybody has any docs or links too share, I’m sure there would be a few people here who would be grateful. 


Addendum: I found Topaz Studio only uses ProPhoto RGB, so at least one plugin doesn't work in the L* workspace.  I imagine now others might not.  I use this for sharpening, but found a workaround.  Save in ProPhoto, open in PS and convert to L*, open the original (already worked over file) and Topaz Edited file together in Layers in L* workspace, and blend the Topaz processed file in Luminosity mode.  Yet more time ...
« Last Edit: January 08, 2018, 07:57:10 AM by Brad Paulson »

Offline Juan Pascual Garrido

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Re: Hasselblad RGB and L*
« Reply #16 on: February 14, 2018, 04:13:20 AM »

Thanks Brad and friends, you´re very helpful for me. But I have two questions:

 -- After work at L*RGB, when you export the Tiff-16, what´s the best Hasselblad profile: Rec.709, 330Skel or 350Skel?

-- I never print, I always send my final tif or jpg to my clients. In Phocus, which one is the best Reproduction mode to use: Standard, Reproduction or Low Gain Reproduction?

Thanks a lot!

Offline Alex

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Re: Hasselblad RGB and L*
« Reply #17 on: February 14, 2018, 04:25:23 AM »

 -- After work at L*RGB, when you export the Tiff-16, what´s the best Hasselblad profile: Rec.709, 330Skel or 350Skel?

Stay in L*RGB (export as source), being an L* and not a gamma based profile (like ProphotoRGB), it's a better workspace profile to work in (or if the subject matter is not too colorful, you can output into EciRGBv2.icc as it is also uses a L*curve). Once you're finished then you can convert it for archive in ProPhotoRGB.icc

-- I never print, I always send my final tif or jpg to my clients. In Phocus, which one is the best Reproduction mode to use: Standard, Reproduction or Low Gain Reproduction?


The different Reproduction modes are essentially different curves applied to the Raw image - so it all depends what kind of look you are after - however if you're looking for the best view of the linear original image then use Low Gain Reproduction.

Offline Juan Pascual Garrido

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Re: Hasselblad RGB and L*
« Reply #18 on: February 14, 2018, 05:53:27 AM »
Thanks Alex!  :)