Magenta cast in self-developed C41

[koraks]

That said, I’m quite confident you can reliably use the bleach many times over.

Indeed, you can. I one shot developer and fix, but not bleach. Bleach just lasts and lasts. So I replenish that, but at higher rates than the manufacturer (Fuji in my case) prescribes. So to the advice of sticking to Kodak guidelines I'd only add to also look at the datasheets of the manufacturer or your chemistry. Don't assume the Kodak replenishment rates will hold for your Fuji bleach - in fact, you'll see that such rates are specific to the product and actually vary within the same manufacturer.

 

[Scott J.]

Didn't know that the bleach and fix times were only 1m and 2m for Flexicolor RA. I was doing 6m 30s each for bleach and fix on the standard Fuji chemicals, so it should save a lot of time.

Yeah, the RA versions are a great time-saver. When I first started using the Flexicolor chemistry, I used the standard (non-RA) bleach and fixer that require 6:30 each. The reason I switched to the RA chemicals was because I began to wonder if the reason I was unhappy with my color negative scans was due to inadequate bleaching and fixing. Inadequate bleaching and fixing are known to produce muddy, grainy, undersaturated color negatives (and transparencies, for that matter). I began to wonder if, in my lack of experience with Flexicolor chemistry, the bleach and fixer concentrates had “gone off” after six months. I even tried bleaching and fixing for longer time intervals (10:00 each) to see if that made a difference (it didn’t).

When I got my hands on fresh RA bleach and fixer, the first thing I did was expose two sheets of Ektar and two sheets of Portra 400 (with identical exposure settings for the two sheets of each film type). I then developed a control set of Ektar and Portra 400 using the standard bleach and fixer, and then developed an experimental set with the RA versions (all time intervals by the book). The control and experimental negatives all looked indistinguishable on a light table. Shortly thereafter, I got my Imacon scanner and scanned the negatives. Again, the results were indistinguishable between the non-RA and RA chemicals.

 

[Lucas Yan]

@Scott J. I did some experimenting with VueScan today and tried changing the RGB gain values. While that did not lead to a usable image, it showed that any adjustment to any color channel could lead to strong color casts after running it through Negative Lab Pro, ones that it is not able to analyze and correct. I have been using auto exposure in VueScan which leads me to think that VueScan can't figure out proper channel exposures for Kodak professional films. I have scanned lab-developed Portra rolls successfully with a digital camera so NLP doesn't seem to be the issue either. This makes sense since both VueScan and Silverfast can work with all scanners but are optimized for none (especially not a discontinued scanner like the Coolscan). The only official software for the Coolscan is Nikon Scan so I booted up a Windows XP virtual machine today and installed Nikon Scan on it. Then I rescanned the negative with no color correction enabled and got this:

Although slightly desaturated (expected since the whole saturated/pastel film trend only started recently), it seems to be devoid of color casts. It looks like the Coolscan as a device is able to handle tricky modern films like Portra or Ektar but only with the first-party driver and software. It's definitely a hassle (and slightly slower) to scan film through a virtual machine though.

 

[MattKing]

Every piece of scanning software is equally capable of working with every film.
The only difference is that the pre-set profiles that are either built into the software or accompany it include "guesses" about colour balance and contrast. Some guesses may be well suited to much of your use, while others won't be. It is the luck of the draw.
If the built in profiles don't work for you with a particular scanner scanning a particular film that depicts a scene with a particular lighting situation, you need to customize the software settings for your use

 

[Scott J.]

The only official software for the Coolscan is Nikon Scan so I booted up a Windows XP virtual machine today and installed Nikon Scan on it. Then I rescanned the negative with no color correction enabled and got this:

Although slightly desaturated (expected since the whole saturated/pastel film trend only started recently), it seems to be devoid of color casts. It looks like the Coolscan as a device is able to handle tricky modern films like Portra or Ektar but only with the first-party driver and software. It's definitely a hassle (and slightly slower) to scan film through a virtual machine though.

I also had much better luck with NikonScan than either Vuescan or Silverfast. In theory, what Matt King suggests about every piece of scanning software being equally capable would be true if every piece of software interpreted the scan data the same. But of course, that's not what they're doing. The crux of the issue is the color inversion process. Even if you're simply scanning in standard RGB mode (i.e., no built-in film profile applied), the preliminary color inversions performed by Vuescan and Silverfast (i.e., what you see after the preview scan) are going to be different, sometimes wildly so. This is because they've been programmed by different engineers with different criteria for what constitutes a successful inversion. Of course, all the data is in there, somewhere (this might be what Matt was referring to), but you're going to have to dig to get at it. You might be able to apply enough post-inversion corrections in those programs to land on something you like - and if you do, be sure to save those corrections as a custom profile -- but in my experience, both of these software packages produced results that were so far removed from satisfactory that it was usually impossible to get a good result. My impression is that the accuracy of their respective inversion algorithms are biased toward certain colors, to the extent that some color ranges get correctly inverted while others do not, resulting in different colors in the image getting compressed into similar parts of the color space. Once that happens, it becomes difficult to selectively tweak one color range without adversely impacting another (hence, manifesting in what appear to be color shifts). I found Flexcolor to be more sophisticated at doing color inversions, but everyone's opinion will differ.

Regarding NikonScan, I was able to get it running on a 64-bit installation of Windows 10 (instructions can be found here: https://lincolnscan.co.uk/Using NikonScan.html). I agree with you that the OEM software is probably better at utilizing the full potential of these scanners, the workflow problems notwithstanding. It seems most people are using Vuescan and Silverfast because they obviate the problem of having to dig up old drivers and operating systems, not necessarily because they're better (in the aesthetic sense).