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Author Topic: Capture One Pro 10 and Deconvolution Sharpening  (Read 4130 times)

hubell

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Capture One Pro 10 and Deconvolution Sharpening
« on: December 06, 2016, 08:35:25 AM »

The Deconvolution Sharpening tool included in C1 Pro 10 appears to be a "one size fits all" adjustment. There are no sliders that can be used to adjust the parameters of the sharpening such as radius and amount. These adjustments are possible with all of the other Deconvolution Sharpening tools I have used. I doubt that C1 10 is applying some sort of automated image analysis algorithm to determine the optimal settings, because the time delay in processing this adjustment is not that long at least on my Mac Pro. OTOH, I generally found that the same settings in Focus Magic worked quite well for almost all of my high res files.
It will be interesting to compare the new Deconvolution Sharpening in C1 10 with Focus Magic. Has anyone taken the time yet to do that?
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Cem

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Re: Capture One Pro 10 and Deconvolution Sharpening
« Reply #1 on: December 06, 2016, 09:45:10 AM »

I am also interested in this. I did some superficial testing. It seems that the driving parameters are automatically based on two things: the aperture and the pixel pitch of the sensor. I can see that the higher aperture pictures with the same camera/lens are sharpened more whereas the lower aperture ones are almost unaffected. I could not detect any halos or other aberrations, which is a good thing. I normally use Focus Magic for critical deconvolution sharpening, which most of the time takes away the need for creative sharpening except for some additional clarity. Whereas the deconvolution sharpening by C1 usually requires some additional sharpening to be applied in later stages of pp. Perhaps Bart will chime in later. 
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hubell

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Re: Capture One Pro 10 and Deconvolution Sharpening
« Reply #2 on: December 06, 2016, 11:06:05 AM »

I am also interested in this. I did some superficial testing. It seems that the driving parameters are automatically based on two things: the aperture and the pixel pitch of the sensor. I can see that the higher aperture pictures with the same camera/lens are sharpened more whereas the lower aperture ones are almost unaffected. I could not detect any halos or other aberrations, which is a good thing. I normally use Focus Magic for critical deconvolution sharpening, which most of the time takes away the need for creative sharpening except for some additional clarity. Whereas the deconvolution sharpening by C1 usually requires some additional sharpening to be applied in later stages of pp. Perhaps Bart will chime in later.

It is interesting that C1 10 still leaves the "regular" sharpening tool on with its default settings, even if the Deconvolution Sharpening is turned on. Perhaps this is not surprising in that C1 10 seems to have a very different concept of "capture sharpening" from what I have always understood to be the function of "capture sharpening." C1 10 only speaks to the use of the Deconvolution Sharpening tool to overcome diffraction from the use of smallish apertures. I have always worked on the premise that ALL digital files required some amount of sharpening to deal with the the loss of resolution from the bayer sensors. Diffraction was another issue that would be addressed at the same time. Deconvolution sharpening tools like Focus Magic just worked well to  bring out detail without creating ugly artifacts in the process. Perhaps this is all a matter of semantics, as I don't really understand the science behind it; I can just tell what looks good in print.
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BartvanderWolf

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Re: Capture One Pro 10 and Deconvolution Sharpening
« Reply #3 on: December 06, 2016, 11:07:22 AM »

The Deconvolution Sharpening tool included in C1 Pro 10 appears to be a "one size fits all" adjustment. There are no sliders that can be used to adjust the parameters of the sharpening such as radius and amount.

Hi,

In a way that's correct. The control is labeled 'Diffraction`Correction' and it looks like that is exactly what is being deconvolved, nothing more nothing less. It therefore does not require additional controls (assuming they did their homework). Diffraction is a constant "blur" per unit area based on Aperture and Wavelength. Because the Bayer CFA lumps many wavelengths in each (usually) R/G/B filter bandpass, one could take an assumed average wavelength for each filter.

The only things that can change the 'amount' of blur per pixel, are sensor element aperture shape/size as concentrated by optional micro-lenses, and focus distance (= magnification factor). Denser sampling (with smaller sensel pitch) of the given diffraction pattern will sub-sample the diffraction pattern in more detail, and thus it will be spread over more pixels. Closer than infinity focus, combined with focal length, will magnify the projected image and the diffraction pattern.

I do not yet know if the latter variables are actually used for deconvolution, e.g. by reading them from the EXIF (if available, which might be an issue with some lensmount adapters). It would take a series of additional tests to establish that, but it would be simpler if someone from PhaseOne could chime in and simply clarify that aspect.

Quote
These adjustments are possible with all of the other Deconvolution Sharpening tools I have used. I doubt that C1 10 is applying some sort of automated image analysis algorithm to determine the optimal settings, because the time delay in processing this adjustment is not that long at least on my Mac Pro.

A lot of the processing can be optimized, because there are not many variables. If the sensel pitch and magnification refinements are ignored things are really straight forward, but the result will be sub-optimal.  Maybe some average (e.g. 5 metres, or e.g. hyperfocal distance if focal length and aperture are known) is used for distance and the camerera model (Raw file) profile triggers a sub-sampling factor lookup, who knows.

The deconvolution is probably relatively simple (not iterative), and thus won't consume that much time, especially if assisted by GPU an Open CL. Maybe it's more elaborate and adapts to image content, it's their secrect sauce. Anyway, it seems to do its job, even on close-ups.

I tried a close-up test shot taken at f/5.6 and the same shot at f/16, and they looked pretty much the same in the plane of best focus, once both were diffraction sharpened. In theory there is potentially an additional focus shift effect on sharpness when only aperture is changed, which would make testing/comparing a lot more time consuming.

The interesting thing is that it looks like they chose to treat diffraction as a separate blur source. Once that blur is removed (and it dominates at narrower apertures anyway), one can get pretty decent results with subsequent USM like edge-contrast boosts. However, even more detail from lens aberration induced blur could be restored with an additional deconvolution aimed at that different blur pattern., as would be possible for defocus blur with yet another blur pattern. Maybe those are things they want to implement in the future. There is also a risk of exagerating aliasing artifacts, like those caused by sensors without an Optical Low-Pass Filter (OLPF or AA-filter).

Quote
OTOH, I generally found that the same settings in Focus Magic worked quite well for almost all of my high res files.

Yes, but FocusMagic is pretty awesome, and requires an additional host-program like an image editor. The charm of the Capture One approach is that one can do most of the work in the Raw converter itself.

Quote
It will be interesting to compare the new Deconvolution Sharpening in C1 10 with Focus Magic. Has anyone taken the time yet to do that?

As said, FocusMagic can also tackle lens aberration and defocus blur. The mix of several blur sources usually creates a kind of modified Gaussain blur. So it should be able to do even more restoration of the original signal, but it is interesting to see/demonstrate how small the differences are becoming.

FocusMagic will probably need lower settings when the image is already diffraction deconvolved. Lots of testing ahead if we need to get to the bottom of things, but sofar it's a very good step in the right direction. Also the clear separation in the 3-step sharpening, and local sharpening in adjustment layers, is a huge benefit. Capture One Pro already had Sharpening Fall-off correction, we now need to test how that combines with diffraction deblur.

Maybe some answers will already come from the 3-step sharpening Webinar that is planned for tomorrow.

Cheers,
Bart
« Last Edit: December 07, 2016, 06:19:28 AM by BartvanderWolf »
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hubell

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Re: Capture One Pro 10 and Deconvolution Sharpening
« Reply #4 on: December 06, 2016, 03:32:23 PM »

Hi,

In a way that's correct. The control is labeled 'Diffraction' and it looks like that is exactly what is being deconvolved, nothing more nothing less. It therefore does not require additional controls (assuming they did their homework). Diffraction is a constant "blur" per unit area based on Aperture and Wavelength. Because the Bayer CFA lumps many wavelengths in each (usually) R/G/B filter bandpass, one could take an assumed average wavelength for each filter.

The only things that can change the 'amount' of blur per pixel, are sensor element aperture shape/size as concentrated by optional micro-lenses, and focus distance (= magnification factor). Denser sampling (with smaller sensel pitch) of the given diffraction pattern will sub-sample the diffraction pattern in more detail, and thus it will be spread over more pixels. Closer than infinity focus, combined with focal length, will magnify the projected image and the diffraction pattern.

I do not yet know if the latter variables are actually used for deconvolution, e.g. by reading them from the EXIF (if available, which might be an issue with some lensmount adapters). It would take a series of additional tests to establish that, but it would be simpler if someone from PhaseOne could chime in and simply clarify that aspect.

A lot of the processing can be optimized, because there are not many variables. If the sensel pitch and magnification refinements are ignored things are really straight forward, but the result will be sub-optimal.  Maybe some average (e.g. 5 metres, or e.g. hyperfocal distance if focal length and aperture are known) is used for distance and the camerera model (Raw file) profile triggers a sub-sampling factor lookup, who knows.

The deconvolution is probably relatively simple (not iterative), and thus won't consume that much time, especially if assisted by GPU an Open CL. Maybe it's more elaborate and adapts to image content, it's their secrect sauce. Anyway, it seems to do its job, even on close-ups.

I tried a close-up test shot taken at f/5.6 and the same shot at f/16, and they looked pretty much the same in the plane of best focus, once both were diffraction sharpened. In theory there is potentially an additional focus shift effect on sharpness when only aperture is changed, which would make testing/comparing a lot more time consuming.

The interesting thing is that it looks like they chose to treat diffraction as a separate blur source. Once that blur is removed (and it dominates at narrower apertures anyway), one can get pretty decent results with subsequent USM like edge-contrast boosts. However, even more detail from lens aberration induced blur could be restored with an additional deconvolution aimed at that different blur pattern., as would be possible for defocus blue with yet another blur pattern. Maybe those are things they want to implement in the future. There is also a risk of exxagerating aliasin artifacts, like those caused by sensors without an Optical Low-Pass Filter (OLPF or AA-filter).

Yes, but FocusMagic is pretty awesome, and requires an additional host-program like an image editor. The charm of the Capture One approach is that one can do most of the work in the Raw converter itself.

As said, FocusMagic can also tackle lens aberration and defocus blur. The mix of several blur sources usually creates a kind of modified Gaussain blur. So it should be able to do even more restoration of the original signal, but it is interesting to see/demonstrate how small the differences are becoming.

FocusMagic will probably need lower settings when the image is already diffraction deconvolved. Lots of testing ahead if we need to get to the bottom of things, but sofar it's a very good step in the right direction. Also the clear separation in the 3-step sharpening, and local sharpening in adjustment layers, is a huge benefit. Capture One Pro already had Sharpening Fall-off correction, we now need to test how that combines with diffraction deblur.

Maybe some answers will already come from the 3-step sharpening Webinar that is planned for tomorrow.

Cheers,
Bart

Thanks, we all look forward to your findings!
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EsbenHR

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Re: Capture One Pro 10 and Deconvolution Sharpening
« Reply #5 on: December 06, 2016, 11:39:38 PM »

In a way that's correct. The control is labeled 'Diffraction' and it looks like that is exactly what is being deconvolved, nothing more nothing less.
Yes.

It therefore does not require additional controls (assuming they did their homework). Diffraction is a constant "blur" per unit area based on Aperture and Wavelength. Because the Bayer CFA lumps many wavelengths in each (usually) R/G/B filter bandpass, one could take an assumed average wavelength for each filter.
More or less, except demosaicing is nonlinear (well, any good one) so the pattern in the color channels does not really work independently in practice.

Closer than infinity focus, combined with focal length, will magnify the projected image and the diffraction pattern.
Again "more or less", but the details depend on the lens design. In particular, I have learned to watch out for lenses with internal focus as they sometimes behave differently. Also, the metadata for focus distance is abysmal and unreliable for most systems, so Capture One ignores this for now.

The deconvolution is probably relatively simple (not iterative), and thus won't consume that much time, especially if assisted by GPU an Open CL. Maybe it's more elaborate and adapts to image content, it's their secrect sauce. Anyway, it seems to do its job, even on close-ups.
Well, "simple" and "fast" are hardly the same thing, although the term "relatively" can make almost and statement true ;-) Some algorithms are certainly very complex while doing the same thing as a slower simpler variant.

Mathematically you could do deconvolution on a noise-free image by applying a convolution with a precomputed inverse kernel. However, since the RAW data is noisy, that does not work well at all. Also, inverse kernels tends to be very large, so they fail if you have anything resembling a burned out channel in the vicinity.

By the way, a saturated channel is a very difficult situation to handle for any algorithm. I highly recommend watching your exposure histograms for images you may use for deconvolution, although it sometimes cannot be helped.

I think any decent algorithm must adapt to image content. Even Richardson–Lucy deconvolution does that in an indirect way.

The interesting thing is that it looks like they chose to treat diffraction as a separate blur source. Once that blur is removed (and it dominates at narrower apertures anyway), one can get pretty decent results with subsequent USM like edge-contrast boosts. However, even more detail from lens aberration induced blur could be restored with an additional deconvolution aimed at that different blur pattern., as would be possible for defocus blue with yet another blur pattern. Maybe those are things they want to implement in the future. There is also a risk of exxagerating aliasin artifacts, like those caused by sensors without an Optical Low-Pass Filter (OLPF or AA-filter).
We did not implement a deconvolution algorithm until now, because you could usually handle it well with proper sharpening and local contrast. We did not want to introduce this unless it would be clearly better in some way.

Diffraction works as a convolution, but demosaicing is non-linear will not blur like a convolution. An AA-filter works at the scale where it is usually best to be considered part of the Bayer pattern.

Regarding misfocus, you should check out what a real lens does near focus. Deconvolution requires an exceedingly complex lens model to work as intended. It matters a lot how far you are from the optical axis, the distance of the subject and whether you are behind or in front of the focus. I don't think a deconvolution algorithm has a practical advantage over other forms of sharpening in this case, because the kernels are so complex and depends on unknown parameters.

On second thought, do not check out what real lenses do near focus. You will be disappointed and risk becoming bitter and older ;-)

Regards,

Esben H-R Myosotis
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ErikKaffehr

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Re: Capture One Pro 10 and Deconvolution Sharpening
« Reply #6 on: December 07, 2016, 01:41:54 AM »

Hi Esben,

Thanks for info, much appreciated!

Best regards
Erik

Yes.
More or less, except demosaicing is nonlinear (well, any good one) so the pattern in the color channels does not really work independently in practice.
...

On second thought, do not check out what real lenses do near focus. You will be disappointed and risk becoming bitter and older ;-)

Regards,

Esben H-R Myosotis

BartvanderWolf

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Re: Capture One Pro 10 and Deconvolution Sharpening
« Reply #7 on: December 07, 2016, 08:53:03 AM »

Hi Esben,

Thanks for taking the time to chime in. Much appreciated.

More or less, except demosaicing is nonlinear (well, any good one) so the pattern in the color channels does not really work independently in practice.

I understand, there is also a lot of 'luminance' signal that is used in all channels, and given the way human vision works, there is a lot that can be done in weighted RGB, AKA luminance.

Quote
Again "more or less", but the details depend on the lens design. In particular, I have learned to watch out for lenses with internal focus as they sometimes behave differently. Also, the metadata for focus distance is abysmal and unreliable for most systems, so Capture One ignores this for now.

Good to know. Nevertheless, your method does correct diffraction on various close-up shots (with zoomlens and Macro lens) that I've tried. The Macro shots obviously have shallow Depth of field, and diffraction is only addressed in the zone of optimal focus.

Quote
Mathematically you could do deconvolution on a noise-free image by applying a convolution with a precomputed inverse kernel. However, since the RAW data is noisy, that does not work well at all. Also, inverse kernels tends to be very large, so they fail if you have anything resembling a burned out channel in the vicinity.

Yes, real-life situations are more complex than optimal Lab conditions. Noise and clipped channel data are a fact of life.

Quote
By the way, a saturated channel is a very difficult situation to handle for any algorithm. I highly recommend watching your exposure histograms for images you may use for deconvolution, although it sometimes cannot be helped.

I'll have an especially close look at such situations, but your algorithm does pretty well.

Cheers,
Bart
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scyth

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Re: Capture One Pro 10 and Deconvolution Sharpening
« Reply #8 on: December 07, 2016, 12:32:42 PM »

Esben H-R Myosotis

as usual it is good to see an actual developer in the topic !

may I ask a question (sorry if I did not find a clear answer myself elsewhere) - during the export ("process recipe" -> "adjustments" -> "sharpening") does "disable all" also disabling "diffraction correction" (deblur) from "lens correction" -> "lens" tab ?
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BartvanderWolf

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Re: Capture One Pro 10 and Deconvolution Sharpening
« Reply #9 on: December 07, 2016, 01:32:42 PM »

may I ask a question (sorry if I did not find a clear answer myself elsewhere) - during the export ("process recipe" -> "adjustments" -> "sharpening") does "disable all" also disabling "diffraction correction" (deblur) from "lens correction" -> "lens" tab ?

As far as I've understood it, yes, All is indeed All.

It would have been nice to have another recipe option, to only keep Diffraction Correction, but not any other sharpening. It would provide a slightly higher quality baseline image for retouching/post-processing by another program but without risk of halos. As it is now, one would have to manually dial down the sharpening to an amount of zero, and apply no output sharpening to achieve that.

Cheers,
Bart
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FrankStark

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Re: Capture One Pro 10 and Deconvolution Sharpening
« Reply #10 on: December 07, 2016, 07:40:06 PM »

IN the webinar, I asked if the halo suppression would work with plug-ins. The response was (I think) that it will work with any file that Capture One can use. Would halo make any difference to a file sharpened with Focus Magic or Topaz Detail. My understanding is that they do not produce halos anyway, but one can sometimes get an "over-sharpened effect. Would halo suppression work for this?

F. 
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N80

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Re: Capture One Pro 10 and Deconvolution Sharpening
« Reply #11 on: December 07, 2016, 10:30:07 PM »

I am pleased with the direction CO is taking with sharpening but have to admit that it is starting to seem a little overwhelming. I have not played around much in 10 yet but I would be interested in seeing a typical workflow from import to output in regard to incorporating these new features and proofing. Maybe even a custom tool palette that includes each of the various steps? Have PO released a video yet that shows a sharpening workflow with CO10?
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FrankStark

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Re: Capture One Pro 10 and Deconvolution Sharpening
« Reply #12 on: December 07, 2016, 10:37:30 PM »

This seems like a good idea, George.

F.
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myotis

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Re: Capture One Pro 10 and Deconvolution Sharpening
« Reply #13 on: December 08, 2016, 01:27:54 AM »

Have PO released a video yet that shows a sharpening workflow with CO10?

The recording of the webinar Phase did on three stage sharpening is available  on the Phase one youtube channel.

https://www.youtube.com/watch?v=yewZ3YIX7k8

I haven't watched it yet, but I assume it will say something about workflow.

Graham



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BartvanderWolf

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Re: Capture One Pro 10 and Deconvolution Sharpening
« Reply #14 on: December 08, 2016, 04:46:22 AM »

IN the webinar, I asked if the halo suppression would work with plug-ins. The response was (I think) that it will work with any file that Capture One can use. Would halo make any difference to a file sharpened with Focus Magic or Topaz Detail. My understanding is that they do not produce halos anyway, but one can sometimes get an "over-sharpened effect. Would halo suppression work for this?

Hi Frank,

I think that Capture One's halo suppression only works to suppress the halos that its own (USM-like) sharpening produces. So it does not analyze a TIFF that already has halos to remove those, but it rather prevents adding/boosting them as part of its own Rendering process.

FocusMagic does not produce simple halos (over/under-shoots at sharp edges) but can generate 'ringing' artifacts, sort of repetitive waves/ripples with decreasing amplitude, but it is very good at minimizing those as long as the chosen blur width is not set too high.

Topaz Detail has one control (called Deblur) that uses Deconvolution, and that too can generate ringing artifacts which can be mitigated by a suppression control. The Detail enhancements are halo-free.

Cheers,
Bart
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BartvanderWolf

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Re: Capture One Pro 10 and Deconvolution Sharpening
« Reply #15 on: December 08, 2016, 05:14:57 AM »

I am pleased with the direction CO is taking with sharpening but have to admit that it is starting to seem a little overwhelming.

Hi George,

And then there are people who complain that there are not enough new features ... ;)

Actually, Capture One is implementing the sugggestions of the late Bruce Fraser (co-authored by Jeff Schewe), who distinguished between Capture sharpening, Creative sharpening, and Output sharpening as three different stages with different goals. He wrote a book about it.

The Capture sharpening already starts with a very high resolution Raw conversion with very few demosiacing artifacts. It now allows to address Chromatic Aberration and Diffraction blur, as separate Capture process sources of blur.
In addition it allows to use the regular sharpening controls to reduce the blurring effects of residual lens aberrations, and even allows to address sharpness fall-off towards the corners.

For Creative 'sharpening' it offers controls like Clarity and Structure that help local contrast and edge definition, and on adjustment layers it now offers additional sharpening, usually for local enhancements. One might for example be a little light-handed on overall sharpening on portraits, but specifically target eyes and eye-lashes on an adjustment layer.

For Output, which usually involves resampling that creates some blur and may need some additional sharpness to pre-compensate for ink diffusion losses, there are now Process recipe controls with a good on display Proofing capability.

That's basically the gist of it. A typical workflow only involves some basic steps, but depending on subject matter one might spend a bit more time on some of the Creative 'sharpening' aspects.

Cheers,
Bart
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N80

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Re: Capture One Pro 10 and Deconvolution Sharpening
« Reply #16 on: December 08, 2016, 10:01:22 AM »

Thanks Bart. I've read the book...I think...a while back. I've got Shewe's book on printing. I do (only recently) understand the concept of capture, creative and output sharpening. I guess what I'm looking for is a cookbook recipe relative to CO10 since it seems like these tools are scattered around a bit now. Aren't the diffraction and CA tools in the lens palette? Do they require that your specific lens is one they have profiled? I'm also unclear about when and where to take advantage of the new proofing capabilities. Admittedly, a lot of my confusion is because I have not done my homework yet and have not spent time in 10 to put all this together. I'm not really asking for someone here to do this for me, but seeing someone else's workflow is often informative.

I searched the COP10 tutorials but did not see one on sharpening workflow. There is one on the new proofing profile. I will look at the webinar referenced above. Thanks again.
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Re: Capture One Pro 10 and Deconvolution Sharpening
« Reply #17 on: December 08, 2016, 03:23:54 PM »

Thanks Bart.
F.
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Re: Capture One Pro 10 and Deconvolution Sharpening
« Reply #18 on: December 08, 2016, 07:25:06 PM »

Te webinar linked above was helpful.
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Chris Livsey

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Re: Capture One Pro 10 and Deconvolution Sharpening
« Reply #19 on: December 11, 2016, 07:52:15 AM »

Te webinar linked above was helpful.

It is a useful introduction but could have done with expanding the examples or at least adding either a portrait or landscape to that darned still life which by the end I was heartily fed up with.


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