on.raw.photography

One thing seems certain to me: Color Perfect's Saturation has nothing to do with PS Saturation or that of other software. This applies both when adding and removing saturation.
CP Saturation is incredible in terms of color quality and naturalness.
Desaturation is an excellent starting point for black and white.
You don't see two different colors converting to the same tone, as happens with desaturation in general. Here, it seems that all colors convert to distinct tones.
I don't think I'm wrong, at least that's my perception, but it could be that CP converts color to B&W exactly as a B&W film would.

This in itself is already extraordinary. Basically, if I remove the saturation, it's as if I were shooting in analog black and white, with the right conversion of color to tone.

These two examples are proof of this.
I specifically chose two images with a wide tonal range, rich in grays, to get a more accurate idea of the conversion, and the result reminded me of when I loaded my Leica M6 with a roll of black and white film.
We are talking about a basic conversion, without any other intervention on the RGB channels.
I started with a color file, in which I adjusted the color.
All other adjustments were made after conversion.

2012 - photo taken with a Canon 30D camera - Canon EF 50mm f:1.4 USM lens 2017 - photo taken with Fujifilm X-Pro2 camera - Fujifilm XF 18mm f:2 R lens This is where the fun begins. As we said, this excellent conversion is the basis, it is only desaturation. FilmicRelight was not even used. Only adjustments for black and white points, and therefore the resulting contrast. I just wanted to understand how powerful CP conversion is.
There is still a lot that can be done to characterize these images, but I see them as such classic black and white that I would keep them as they are.

The interesting thing may be the adjustments using CC packages to vary the tone of the B&W.
With CC packages, you can pull the tones in any direction you want, changing the appearance of the image. Ring Around can also help.

How do you do it? You may need CC, Tonal, but BP color seems to me to be the most functional.

The CC filter packages aren’t very relevant for black-and-white images. What you want is in the same CC pulldown, under Tonal. There you can adjust the percentages of the three primaries feeding into the final image—exactly the effect you’re after.

Tonal can be very relevant, since with it you can emulate yellow, green, or red filters. Just keep in mind that extreme settings, like pushing everything through 100% red, will carry all the noise from that channel into the final image. A good approach is to first restore saturation to 100, exit PerfectRAW, and denoise the file.

For a simple workflow: because we’re heading to black and white anyway, convert the image to L*a*b*, apply Photoshop’s Dust & Scratches filter with a radius of about 5–6 pixels on both the a* and b* channels, then convert back to your original RGB working space. After that, return to TouchUp, set saturation to zero, and fine-tune Tonal. The L*a*b* step equalizes channel noise without affecting image brightness, so your final monochrome will be cleaner while retaining tonal integrity.

Something I’ve wanted to do for a long time, but never quite got around to, is make a copy of the virtual grades I’ve been using for decades on black-and-white negatives that works directly on gamma-1 encoded positive input data, so that we could stay in ColorPos mode.

And frankly, since we’re talking about targeting black and white, there’s really no need for PerfectRAW. Color fidelity of the camera doesn’t matter here—we’re only after brightness, and for that the three color channels in the RAW file are fine without any PerfectRAW processing. In fact, using it could potentially just add noise.

I haven’t tried this yet, but what I would suggest is opening the RAW image derived from MakeTIFF in TouchUp mode, pressing the GL button if you have it (or otherwise setting the input to linear), and then simply OK-ing out. This will gamma-encode the image. At that point, apply the L*a*b* trick I described earlier, and thereafter continue working in ColorPos mode. For that workflow, I plan to contribute a set of virtual grades for black-and-white if people here are interested.

It should be noted that in its default configuration, ColorPos mode expects gamma-encoded input, which is why I haven’t said much about it above. If you have the GL button, that’s supposed to be G in that step. If you have Input Gamma C configured, then the pull-down menu should show the same encoding as your output menu, since we already gamma-encoded the file in TouchUp mode.

Should this operation in PS Lab always be performed, even with a sensitivity of 100 ISO, or only with higher sensitivities such as 400, 1600, 3200 ISO, etc.?

So I would proceed as follows.

In PerfectRAW, I convert to B&W and process the entire B&W image in all its values.
I don't use CC Tonal.
I reassign Saturation to 100.
I go back to PS and apply Dust and Grain using the Lab method.
I convert back to the original profile and call up TouchUp.
From here, I convert back to B&W, adjust with CC Tonal, and if necessary, refine the other adjustments.
When I don't find it necessary to adjust CC Tonal because I'm happy with the basic conversion, I imagine I can skip the Lab PS step?

Okay, this new information you've posted makes me reevaluate the issue.
I'll do the tests.

I am proceeding with the second solution.
After running TouchUp in linear + dust and grain (in CS6 dust and scratches) in Lab, I am now in ColorPOS.
I have my color image in G.
At this point, I don't need to balance the color, because we said we're not interested in that. I immediately desaturate and then proceed with the adjustments.
Or do I still need to balance the color first?

Now, with ColorPOS, I can work with FilmType/SubType/FilmGamma

robyferrero wrote: Sat Sep 20, 2025 3:43 pm At this point, I don't need to balance the color, because we said we're not interested in that. I immediately desaturate and then proceed with the adjustments.
Or do I still need to balance the color first?

No need. Just set saturation to zero and work directly with Tonal for full control.

To clarify something I phrased imprecisely earlier: the L*a*b* detour does not “cure noise” in a magic way. What it does is recompute brightness from all three channels together, then, by blurring the a* and b* channels with Dust & Scratches, it evens out detail mismatches between red, green, and blue. The result is that the weaker channels — red and blue — actually gain detail and stability, since their noise is diluted by information from all three channels. Green, on the other hand, already carries the strongest signal because half of all sensor sites measure green. In theory, it could lose a touch of detail in this process. If that’s a concern, you can always keep a copy of the green channel before the L*a*b* step and restore it afterward.

All of this can be scripted. A Photoshop action can store the green channel by copying it, to paste it back later, run the L*a*b* Dust & Scratches routine on a* and b*, convert back to RGB, and then paste green back in if you want to ensure no loss there. That way the workflow becomes repeatable and quick, while still giving you the benefit of cleaner red and blue channels for Tonal adjustments.

This is also why the step matters before extremer Tonal. For example, if you set Tonal to 100% blue, you are effectively telling the program to take luminance only from the blue channel. Any defects or noise in blue then dominate the entire image. Without the L*a*b* preprocessing, Tonal adjustments can therefore make noise and detail issues worse. With it, you have a cleaner, more consistent basis, so Tonal really works as intended — emulating filters without dragging channel weaknesses into the whole picture.

Of course, if you already apply a solid pre-MakeTIFF denoising workflow, this benefit may be way less dramatic. But as a built-in Photoshop step, it remains one of the few methods that can genuinely improve channel quality, not just shuffle values around.

Interesting.
A: If you decide to leave a basic conversion without using CC Tonal, is the Lab CS step necessary?
B: If you perform noise reduction before Make Tiff, the Lab process is less noticeable, but I guess it's still a good idea to do it?
C: Obviously, the Lab method is not intended for color, to avoid losing color integrity?

With this workflow going from TouchUp and then ColorPOS, it seems right to work in ColorPos - G RGB.

robyferrero wrote: Sat Sep 20, 2025 6:21 pm A: If you decide to leave a basic conversion without using CC Tonal, is the Lab CS step necessary?

Then it should have no benefit, and it should do no harm either. We are talking about B&W here.

robyferrero wrote: Sat Sep 20, 2025 6:21 pm B: If you perform noise reduction before MakeTiff, the Lab process is less noticeable, but I guess it's still a good idea to do it?

Again, it should do no harm, but I would hope channel differences to have been evened out.

robyferrero wrote: Sat Sep 20, 2025 6:21 pm C: Obviously, the Lab method is not intended for color, to avoid losing color integrity?

Actually, that depends. If you want to make major Tonal adjustments to a color image, a careful version of this should be able to help in the same way. The thing to watch out for is that color edges do not gray out or bleed.

Say you have relatively small red lips and you were to apply a Gaussian Blur to a* and b*—then you would see a detriment to the color at the edge of those lips. That is why I suggested using the edge-aware Dust & Scratches instead. With it, the lips should remain as sharply defined color wise as possible with the right radius. That radius is subject to experimentation, and my suggested values were only educated guesses.

robyferrero wrote: Sat Sep 20, 2025 6:24 pm With this workflow going from TouchUp and then ColorPOS, it seems right to work in ColorPos - G RGB.

For B&W yes - even though it makes the naming weird, always RGB because RAW implies color conversion math we do not need - but which won't be a problem either. The purist answer is still RGB

C.Oldendorf wrote: Sat Sep 20, 2025 7:07 pm

robyferrero wrote: Sat Sep 20, 2025 6:24 pm With this workflow going from TouchUp and then ColorPOS, it seems right to work in ColorPos - G RGB.

For B&W yes - even though it makes the naming weird, always RGB because RAW implies color conversion math we do not need - but which won't be a problem either. The purist answer is still RGB

RGE

Great, that was an easy thing to fix but it had to be noticed first. Thanks.

C.Oldendorf wrote: Sun Sep 21, 2025 7:26 am Great, that was an easy thing to fix but it had to be noticed first. Thanks.

Of course, I should have put it in the Bugs Topic.

I reworked the two previous examples with the ColorPOS module.
Here you can compare the results between PerfectRAW and ColorPOS.
The workflow is always the same for both modules; basic desaturation without the intervention of CC Tonal.
Graduated White and Exposure with the same parameters, not numerical, but modus operandi, that is, I stopped them at the same points on the histogram, useful for having a yardstick. So it can be argued that they are not technically identical, but they are identical in their shadow and highlight stops appropriate to the two different photographs. I don't know if I've explained myself well
This modus operandi was adopted not only in the comparison between the two modules, but also between the two photographs with different subjects.

The B&W processed with ColorPOS is technically better and more beautiful in appearance.
It appears denser, with darker shadows, but they seem to be darkened in the right places, preserving detail.
I won't comment on the contrast, because it seems to me that some areas of one are more contrasted than some areas of the other, and vice versa.
Perhaps one could say that PerfectRAW is more contrasted, and ColorPOS is denser and deeper.

Here, in the comparison, you can see the difference between the two.

Here is the second example.
In this comparison, however, the differences between PR and CoP are similar to the previous comparison, but not completely identical.
In fact, PerfectRAW remains more contrasted, but ColorPOS is less dense and deep.
I would think that, being a basic desaturation without the intervention of CC Tonal, the green of the leaves remains brighter and softer, less dense. The contrast also seems weaker, but I think it is only perceptually weaker, that is, it could be the right contrast for this photograph, for this light, and for this green color.
It should be remembered that the two photographs, or rather the four examples, were processed in exactly the same way. As described above.
It follows that, between the two different photographs, if one scene is more contrasted than the other, with the same modus operandi, the result will always be that one remains more contrasted than the other. As it should be.
I mean, there is no risk of giving too much contrast to one or too little to the other.
The contrast is just right, especially if you can find the right point where to stop the black and white.
In this way, you don't add excessive contrast, what I call software contrast, i.e., excess contrast, but you exploit and enhance only the real contrast of the scene.

If one scene is softer than the other, when you identify the precise point of black and white, the rest no longer matters. That's fine; if it's soft, it remains soft, but it will be a softness with the right contrast for that scene to be printed on paper. It will be the contrast recorded by the sensor, without the addition of contrast from software.
If the scene is more contrasted, it will be the same as above, but instead of being soft with the right contrast, it will be contrasted with the right contrast.

The point is to find the exact stop on both the right and left, which is the stop I'm not sure I've found yet.
Once the stop point has been found, all photos in the world are the same, they all come out the same, but they will all be different; on the right and left, in blacks and whites, in shadows and highlights, they will all be the same in the mutual correspondence of the values recorded in the sensor, the diversity will be in the middle, which will gradually decrease as the extremes are reached.

There is a first point that says stop, going beyond this point is “excess.”
It is possible, in fact I think that many photographers go beyond it, but in practice it would serve no purpose other than personal interpretation, artistic form.
One could say that up to that first point it is merely an enhancement of the sensor data, beyond that point it is artistic interpretation.

I can understand the relativity of this concept, albeit technical, but we have to start somewhere.
Then, if everything is the opposite of everything else, personal, artistic interpretation refutes this thesis.
But that's another matter. I interpret too.

But if I have to think in technical terms, or better still, as a purist, this is how I understand the technical and expressive side of photography. Right or wrong.

A rigorous philosophy, which is also evident in Color Perfect when it talks about color integrity.

The histogram example.
I show the histogram for immediate understanding.

One thing must be said: although this example created with PerfectRAW and ColorPOS appears smooth, the darker shadows and black play a nasty trick.
In the histogram in the example above, you can see that the left side is too crowded for my taste.
I don't know if this is right or wrong, better or worse.
What I do know is that I would personally prefer the left side to be a little more pyramid-shaped, tapering off.

Now, I haven't yet fully figured out how to make the left side less crowded and more progressive.

You can lighten it a little with BPTails, with Graduated White, but not much if you want to preserve the black point. Furthermore, this way you work on the entire image and not just on the last one or two areas. So you have to make a second copy and merge the two areas into the first copy.

In some circumstances, Color Perfect itself provides for merging two copies, albeit for other reasons. So far, so good.

Another solution, perhaps more appropriate, more practical, and faster, is to work directly on the Color Perfect areas. This is an excellent method. I do it with the highest area to avoid extreme brightness and preserve the texture.

But when it comes to the shadow area, I find it more difficult to manage.
For example, blocking zone V and adjusting zone II allows you to control the value of the medium-low shadows, i.e., from zone IV to zone I.

Here, in my case, to correct this type of histogram, we are talking about controlling only zone I and perhaps II.
I don't know whether to lock zone II to move only zone I, with the risk of making the transitions more abrupt and less gradual. Or lock zone III and move I and II to have a more gradual transition.
And zone 0? How can something be done in zone X, is it possible to improve zone 0 as well?

After all this, or at least everything I've tried to do, I haven't been able to bring the extreme shadow area to a more pyramidal, less crowded value.
I recover something, yes, but the crowding remains.

I understand that if the file is recorded that way by the sensor, it's probably the fault of the exposure, or the excessive contrast of the scene, in which the dynamic range can't do much unless you want to burn the highlights.

But are the solutions I use to overcome this problem, if it is indeed a real problem, correct? Is one method better than another, or are there other methods?

Can't say, as we are viewing derivatives. Let's look at the raw image of the green leaves.

This is the bright green RAF file.

Thank you. I'm still wrestling with the display glich bug you found. Sneaky thing...