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Photo Retouching "Improving" photos, post-production, correction, etc.

is it better to start retouch with a flat image?

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  #51  
Old 04-12-2015, 04:31 PM
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Re: is it better to start retouch with a flat imag

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Originally Posted by creativeretouch View Post
Exactly =)
I then decided to make a program that would allow me to operate with color as I imagined it in my head. That is how I came up with the idea to have a grid, based on the LAB color model. Later I realized that the LAB color model is not the best option for working with photos, and I came up with my own color models. I also added in a lot of other tools, which I did not have, and they all become unique. Oleg Sharonov - http://3dlutcreator.com"
Very interesting looking product, thanks for sharing. I downloaded the demo, want to check it out. I’ve never spent too much time looking at LUTs in PS because the lack of tools to create them. The one’s Chris Cox at Adobe built and supplied were more “Proof of concept” than useful. I know Adobe’s SpeedGrade can build them, I’m a CC subscriber but never went that far. This product potentially could be an easier path to building LUTs.
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  #52  
Old 04-12-2015, 04:33 PM
creativeretouch creativeretouch is offline
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Re: is it better to start retouch with a flat imag

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Originally Posted by klev View Post
I mentioned it to dispel some misconceptions. It's more complex than saying L*AB allows you to deal with luminance separately, but yeah I have quite a few (overlapping) reference books.





I think I see the point of contention, although I'm not positive I can offer a satisfactory explanation. I'm unfamiliar with Poynton's work. Anyway my point was that there is still a difference in encoding. Cameras have differing dynamic ranges. I mention cameras, because I'm considering the reconstructed signal range, which is dependent on more than the raw sensor data. This has to be mapped into a fixed range. Now obviously prophoto 1.0 has a fixed range, but to output to an unsigned integral encoding rather than a floating point type, you have to clamp anything that falls outside of a normalized range. I would have to test this to see how it impacts the results. Photoshop can only "properly" deal with gamma 1.0 data in 32 bit mode, but I would have to see how it works going from that profile to 32 bit mode. I doubt it's possible to write an export script to avoid the encoding and clamping issue.

I think we discussed this once a long time ago, but 16 and 32 bit modes do interpret the data differently. It's not even the number of bits. If you open a 16 bit EXR, it will be opened sign extended in 32 bit mode. These are implementation details that are not directly related to the number of bits assigned. If you store something in a floating point encoding, you have specific bits assigned to a signed exponent value, allowing for an extended range at the cost of some precision (can link a reference to all of the fl(something) math, but it's time consuming to read).
I tried to compare adjustments of 32 bit mode floating point on single image in Lightroom with luminosity masking in Photoshop and I got better result with luminosity masks. It depends on the content of the image I would say, but this is interesting technique too. But I am not too familiar with the theory behind.
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  #53  
Old 04-12-2015, 04:38 PM
skoobey skoobey is offline
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Re: is it better to start retouch with a flat imag

At this point I think that everyone is more or less agreeing on what we have to work with. I am not a developer, so I can't help anyone on any of the faults of current systems.

Klev, Andrew, CreativeRetouch, yes I get all the things you have said.

On another note, all that talk about 32 bit is just useless at this point, you all get that, right? So many adjustments that you want to make(like filters) work only in 8bit, some in both 8 and 16 bit, so all this discussion about how the alternate color profiles in 32bit isn't going to be very helpful when you have pieces of the image that contain only 8bit detail(talking about the least destructive way of exporting things o be adjusted to 8bit, and then making them part of the 32bit image yet again).

I'm eager to learn, but I think I'd wait a bit for the actual program to catch up and let me actually use the profile, so I'm sticking to CMYK provided by the client or Adobe RGB.

And on top of that, as Klev said, working in 32bit vs 16 is not the same as 16 vs 8 bit.

Last edited by skoobey; 04-12-2015 at 04:44 PM.
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  #54  
Old 04-12-2015, 04:40 PM
creativeretouch creativeretouch is offline
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Re: is it better to start retouch with a flat imag

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Originally Posted by andrewrodney View Post
Very interesting looking product, thanks for sharing. I downloaded the demo, want to check it out. I’ve never spent too much time looking at LUTs in PS because the lack of tools to create them. The one’s Chris Cox at Adobe built and supplied were more “Proof of concept” than useful. I know Adobe’s SpeedGrade can build them, I’m a CC subscriber but never went that far. This product potentially could be an easier path to building LUTs.
I see this software as a great "color grading" tool. You can save edited image or export this image to Photoshop and see changes in real time. There is interesting tool where you have LAB L curve together with RGB curves in one place and you do not need to change color space. Also saturation curve. And many other tools which are not present in Lightroom or Photoshop.
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  #55  
Old 04-12-2015, 04:44 PM
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Re: is it better to start retouch with a flat imag

I’ve been begging Adobe for a saturation curve in PS since last century. It fall’s on deaf ears. It was a feature in LinoColor I used all the time.

Skoobey, yes I agree about the 32 bit mode in terms of this discussion.
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  #56  
Old 04-12-2015, 04:50 PM
skoobey skoobey is offline
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Thumbs up Re: is it better to start retouch with a flat imag

Oh saturation CURVE, or even SATURATION LUT (as in map of the saturation so that you can shift the saturation of desaturated areas towards the higher saturated parts, and the opposite, and anywhere in between).

I wonder how would that work considering that current math doesn't include surrounding pixels when increasing saturation, so we can end up with less than ideal transitions, but as a general idea YES YES YES.

EDIT: OMG I can't believe they neglected this for so long, coming to think of it I use curves to adjust saturation here and there(mostly to linearly desaturate shadows) but it so crude.

Last edited by skoobey; 04-12-2015 at 05:37 PM.
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  #57  
Old 04-12-2015, 08:35 PM
klev klev is offline
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Re: is it better to start retouch with a flat imag

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Originally Posted by andrewrodney View Post
So, if we have a 1.0 TRC color space with ProPhoto primaries, and that’s what I’m told by people like Thomas is used in the ACR engine, and I can render in a color space with same TRC and primaries, I’m confused by this:What you see in the raw processor window is a representation of how the image will appear mapped into a gamma corrected space with a smaller volume than the source gamut.
I mix details up sometimes. Sorry about that.

ACR can produce computed values for pixels that map to 0 or 255 by adjusting the exposure slider. It wouldn't be able to do that if it could only store normalized values (equivalent to 0-255 in 8 bit mode or 0 to whatever they use in 16 bit mode). Come to think of it I'm not sure at which stage or stages they clamp the values, but it certainly happens, as 8 and 16 bit modes don't support floating point encodings. As I mentioned OpenEXR and HDR formats open in 32 bit mode regardless of whether they're stored at 16 bits (half precision) or 32 bits (full precision). Anyway they would have to convert those values to an integer representation, and anything clamped is basically lost. It's more limiting than the raw capture data, but beyond that I haven't been able to get something to work where I have a "normal" looking image for viewing purposes with all adjustment curves and things removed. Certainly you can make contrast curve adjustments in Lightroom, but you can't really export to the point where gamma and other fundamental adjustments are applied for viewing preview/ viewing purposes only.

I also commented that video has kind of gone the other way.


Quote:
Originally Posted by skoobey View Post
Oh saturation CURVE, or even SATURATION LUT (as in map of the saturation so that you can shift the saturation of desaturated areas towards the higher saturated parts, and the opposite, and anywhere in between).

I wonder how would that work considering that current math doesn't include surrounding pixels when increasing saturation, so we can end up with less than ideal transitions, but as a general idea YES YES YES.

EDIT: OMG I can't believe they neglected this for so long, coming to think of it I use curves to adjust saturation here and there(mostly to linearly desaturate shadows) but it so crude.
That would be pretty neat. Highlights tend to converge a bit more than deeper values.

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Originally Posted by creativeretouch View Post
I tried to compare adjustments of 32 bit mode floating point on single image in Lightroom with luminosity masking in Photoshop and I got better result with luminosity masks. It depends on the content of the image I would say, but this is interesting technique too. But I am not too familiar with the theory behind.
Well I haven't compared that way, so I'm not sure. I like the tool you linked earlier. It's neat. Graphics can be a pretty tough area, especially in the modern sense where the trend is toward highly parallel indirect solvers.
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  #58  
Old 04-13-2015, 09:14 AM
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Re: is it better to start retouch with a flat imag

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Originally Posted by klev View Post
I mix details up sometimes. Sorry about that.
No worries, happens to me more and more these days.
Quote:
ACR can produce computed values for pixels that map to 0 or 255 by adjusting the exposure slider. It wouldn't be able to do that if it could only store normalized values (equivalent to 0-255 in 8 bit mode or 0 to whatever they use in 16 bit mode). Come to think of it I'm not sure at which stage or stages they clamp the values, but it certainly happens, as 8 and 16 bit modes don't support floating point encodings.
I’m not clear on how any of this affects the gamut, it shouldn’t should it?
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  #59  
Old 04-14-2015, 02:46 PM
klev klev is offline
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Re: is it better to start retouch with a flat imag

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Originally Posted by andrewrodney View Post
I’m not clear on how any of this affects the gamut, it shouldn’t should it?
Well typically we examine gamut only for normalized values and clamp anything out of range. Depending on how certain tools are implemented, they may affect the remapped range of the data of one or more channels. It's worth pointing out that you shouldn't necessarily lose that much with a single frame, although it would probably be more with an exceptionally high quality sensor.

That aside I'm really hesitant to claim some of these things with too much confidence without testing on the current version of photoshop. It's possible that the 16 bit tools (similar to the 8 bit) do not produce desirable results when using a gamma 1.0 trc, and it may not look as intended when imported in that manner. Again I would have to test.

This kind of came indirectly as a result of the comment "garbage in garbage out" in regards to zeroing sliders. In theory assuming a decent signal reconstruction and output of data with only necessary interpolations and possibly minor noise filtering made, it should be possible to achieve similar results using adjustment layers that can be continuously modified. It's just not really the case (and not practical) if the tools aren't aren't really designed to work with the data as it's given. There are certainly tools that try to put this kind of computation out further, but they're mostly relegated to film editing tools.
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  #60  
Old 04-14-2015, 02:56 PM
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Re: is it better to start retouch with a flat imag

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Originally Posted by klev View Post
Well typically we examine gamut only for normalized values and clamp anything out of range. Depending on how certain tools are implemented, they may affect the remapped range of the data of one or more channels. It's worth pointing out that you shouldn't necessarily lose that much with a single frame, although it would probably be more with an exceptionally high quality sensor.
So you’re referring to the gamut of the capture device (which in the case of a camera gets us into serious issues)? I’m referring to the underlying processing color space in ACR/LR and it’s gamut which by this time, really is within a colorimetrically defined space. It’s ProPhoto RGB primaries. If you ask for that out of the converter, I can’t see how you’d affect gamut.
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