Luminous Landscape Forum

Raw & Post Processing, Printing => Colour Management => Topic started by: HSakols on February 12, 2021, 10:24:33 am

Title: Scanning and Color Space
Post by: HSakols on February 12, 2021, 10:24:33 am

I've been making a number of scans on my old Minolta Multi Pro using Vuescan.  The scans were outputted as lossless tiffs but were assigned sRGB by Vuescan.  Can I just reassign the ProPhoto working space in Photoshop since they are raw scans, or do I need to rescan? 

Title: Re: Scanning and Color Space
Post by: digitaldog on February 12, 2021, 10:31:01 am

No don’t even think of assigning that color space. Assigning a profile is to provide the scale of the RGB numbers for untagged data. The data is an sRGB. that’s what you got and that is what you are stuck with.

Title: Re: Scanning and Color Space
Post by: HSakols on February 12, 2021, 10:45:17 am

  I will rescan.  I should have caught that.  Thanks again. 

Hugh

Title: Re: Scanning and Color Space
Post by: digitaldog on February 12, 2021, 10:49:38 am

You may want to look over:
http://digitaldog.net/files/06AssignProfileCommand.pdf

Then

http://digitaldog.net/files/06Convert%20to%20Profile%20command.pdf

Title: Re: Scanning and Color Space
Post by: HSakols on February 12, 2021, 11:48:24 am

 There is a ton of good info on your site.  I'll read through the above articles.  Getting the tunes ready for another long scan session. 

Title: Re: Scanning and Color Space
Post by: digitaldog on February 12, 2021, 11:50:58 am

Ideally you want to scan in the “native” scanner color space and archive that, eventually convert to whatever RGB working space or output color space required.

Title: Re: Scanning and Color Space
Post by: MichaelKoerner on February 13, 2021, 01:48:57 pm

Firstly, I agree with Andrew, of course.

But interestingly, on my system (MacOS 10.15/Epson V750/VueScan) any raw tif coming from VueScan appears to be untagged when I open it in Photoshop - no matter what output color space I had chosen in VueScan when saving the file.

So I always have to assign (yes, in this case assign) the scanner profile in PS manually.

I always considered this to be a bug of VueScan, but perhaps I was wrong and the bug was me :-)

According to your first post sRGB is assigned to your raw scans by VueScan. May I ask about your scanning settings and OS?

Best regards, Michael

Title: Re: Scanning and Color Space
Post by: digitaldog on February 13, 2021, 02:00:49 pm

I don't use the product so I can't say if it's a bug or sloppiness. But it should be able to do this.

Title: Re: Scanning and Color Space
Post by: MichaelKoerner on February 13, 2021, 02:05:02 pm

Thanks, Andrew. I just hoped Hugh could give me a hint.

Title: Re: Scanning and Color Space
Post by: HSakols on February 13, 2021, 08:15:07 pm

Yes, now when I open my files in Photoshop, I'm asked to assign the working space.

Title: Re: Scanning and Color Space
Post by: unesco on February 14, 2021, 03:11:21 am

Scan your slide (it won't work well for negatives) and make output from VueScan in Device native color space.

Then (or before), scan the reference IT8 target (also without assigning any color space, just in device native one) and make icc profile with any (reasonable) tool (or maybe you already have scanner profile?).

Then in PS, ASSIGN this made icc profile to the scanned film.

Then CONVERT the color space to ProPhoto, AdobeRGB, sRGB or any other space for further processing.

In overall above processing you do not use any processing from VueScan, everything switched off (I only have Multi-sampling switched on and Lock exposure set to 1.5 - set by experimentation, but every scanner model is different, I use Reflecta ProScan 10T). If you do not have IT8 reference target, you need to play with all the sliders on COLOR tab, and save the image to any of above color spaces (eg. ProPhoto).