Virtual Grades for Black and White negatives

[robyferrero]

I downloaded the virtual gradations VirtSWGrad.negpos

There's only one document, and I'm not sure how to use it on ColorPos, ColoNEG, and PerfectRAW.

Do I have to manually change the extension?

.negpos for ColorNEG
.colorint for ColorPOS
.pfraw for PerfectRAW

Is it possible to duplicate the document and assign different extensions?

I assume it's only useful for black and white?

[C.Oldendorf]

I downloaded the virtual gradations VirtSWGrad.negpos
There's only one document, and I'm not sure how to use it on ColorPos, ColoNEG, and PerfectRAW.

As it stands, I designed the Virtual Grades many years ago to be used exclusively in ColorNeg mode when processing black and white negative film — and only that. For this reason, they are currently available solely as a .negpos file.

It would, at least in theory, be possible to convert the same set into a .colorint file for use in ColorPos mode, but not with identical values. The reason is that the Virtual Grades were built to mimic paper gammas in the analog world. As explained in the corresponding article and according to E. Goldberg’s findings, a truly faithful tonal rendition requires that the paper gamma cancels out the film’s gamma — in other words, film γ × paper γ = 1.

Black and white negative film is not developed to a gamma of 1.0 but to something significantly lower. Therefore, to adapt the same concept for ColorPos, I would first have to decide on an average black and white film gamma to serve as the model. From there, the Virtual Grades could be recalculated to correspond to a gamma = 1 input equivalent, which is what we find in digital originals or positive scans.

Since such an approach would involve working with Tonal and Saturation set to zero, there would be no PerfectRAW variant of it — which is actually preferable, because otherwise it would need to be made per camera, and that is not really feasible.

[robyferrero]

Very interesting.
I haven't had a chance to try them yet,
but I think they might offer more precision for contrast adjustment.

[robyferrero]

Maybe I missed something.
I'm trying to use Virtual Grades on a B&W negative scan, on ColorNEG.
I set it to User. Now I'm stuck; I don't know how to access or work with Virtual Grades.

I'm not sure if Virtual Grades is used for digital reproduction of B&W negatives using a digital camera, or if it's used for scanning from a B&W negative.

[C.Oldendorf]

You're already halfway there. As you correctly figured out, you need to be in the User Maker menu. Once you are in ColorNeg Mode’s User Maker menu, two new buttons appear at the bottom of the plugin: Save and Load.

To populate the list with entries from the Virtual Gradrs file, you need to load it. Simply store the downloaded file anywhere on your Mac, then load that file from within the plugin.

After you’ve done this, exit ColorPerfect with OK, and — after possibly restarting Photoshop — it will remain in place until you load another file. In other words, it will likely stay active for a very long time. The Virtual Grade entries will then reside in the User Maker film list.

[robyferrero]

Okay, I've loaded Virtual Grades.

Let's see if I understand correctly.

If we use Virtual Grades, we don't use FilmType/SubType/FilmGamma. This is because once we exit CP and then re-enter, the latter settings cancel the Virtual Grades settings. If you reset Virtual Grades, the FilmType triad is canceled.

If this is the case, Virtual Grades directs you precisely and arbitrarily to the most appropriate contrast solution for a photograph.
FilmType/SubType/FilmGamma, on the other hand, are tools that, with a trained eye and mastery of the medium, can help you find the contrast, but with more variations available in the ratio of light and shadow.

Using one method or the other, you can get slightly different results, but basically, probably with the same contrast.

If all this is true, it was easier to work with Virtual Grades, precisely because of experience and mastery of the tool.

You know, all in all, I have processed very few scans or reproductions with Color Perfect, if only because I have been working on digital projects for a long time.

These are two examples using two different methods.
These two examples are not extremely reliable because the one performed with FilmType/SubType/FilmGamma has 150 fewer FilmGamma points than the other, which makes it a little brighter, less dense, and less deep.

Without those 150 points, they could be more similar.
If that were the case, I would have obtained very similar results with two different methods.

I don't know if it's because of those 150 gamma points, maybe it is, but personally I prefer the second one obtained with Virtual Grade.
Maybe it's a matter of taste.

2013-001-roby_ferrero.jpg (233.26 KiB) Viewed 210 times

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[C.Oldendorf]

When we talk about the Film Type, Sub Type, and Film Gamma system in ColorPerfect, and we apply that thinking to black-and-white photographs, it becomes clear that Film Type and Sub Type lose their original meaning — but not their effect. In color work, Film Type and Sub Type exist to encode the differences in Film Gamma between the three color channels, while Film Gamma itself acts as the master control that applies a coordinated adjustment across those three. You first establish Film Type and Sub Type to achieve plausible color, and then you set Film Gamma to arrive at the desired overall contrast. The benchmark for that contrast — informed by historic and modern color papers — tends to be around 1.70 as shown in the lower-right readout of the plug-in.

For black-and-white, however, whether we are feeding the plug-in a single channel or three channels with monochrome intent, Film Gamma becomes the only one of the three that matters. At that point, Film Gamma and artistic Gamma converge, because in grayscale there is no color to preserve or restore. In color work, artistic Gamma ensures that a given luminance adjustment retains accurate chromatic relationships. Why is such a mechanism needed? Because the widespread belief that RGB curves change brightness without harming color is incorrect.

Visualize a curve: neutral values have equal R, G and B, so they fall on the same point on that curve and thus receive identical adjustment — neutrality is preserved. But take a bluish shade of green — the kind of tone where green is fairly bright, blue sits somewhere in the middle, and red is quite low. Those three components lie at different positions along the curve, so they are adjusted by different amounts. The result is a visible color shift, and the more uneven the starting triplet and the more pronounced the curve, the further the shift. This is precisely why ColorPerfect’s Gamma operates analogously to Zones or Filmic Relight: it maintains correct chromatic relationships when changing brightness. In monochrome, with chroma absent, that distinction falls away, and Film Gamma essentially is artistic Gamma.

The virtual grades are simply predefined starting points for Gamma, modeled after traditional RC paper grades in the darkroom. In black-and-white photography, the objective often isn't a literal, one-to-one tonal reproduction of the subject — as a perfectly rendered step wedge would imply — but instead an aesthetically appropriate tonal translation that carries the expressive intent of the scene. The “push 1”, “push 2”, “hold 1”, etc. annotations attached to the virtual grades relate to how those grades approximate natural tonal expectations. However, because the virtual grades are based on RC paper behavior, their usefulness does not actually depend on how the film was developed; only the descriptive hints shift slightly in accuracy.

The point of the virtual grades is that I wanted concrete, repeatable tonal stepping in my digital black-and-white workflow, just as I had it in the darkroom — not a perpetual exercise in manually tweaking Film Gamma or Gamma from scratch for every single frame. Working this way feels natural, disciplined and familiar, and avoids the endless fiddling that digital tools sometimes invite.