Pixel Based Editing: An observation and a question about Photoshop & Lightroom

[Thlayle]

This question seems too basic: when working in Photoshop, when by definition, am I actually doing pixel-based editing? I ask since my understanding of digital images and processing them is very limited and I don't believe EVERYTHING done in Photoshop is actually working at the pixel-based level. This image is a layered composite of three images, first processed in Lightroom and then opened as layers in Photoshop. Once grouped as layers in Photoshop, I simply used 'Lighten' as my layer modes for the top two layers and I did some masking out of the sky so I could add a brightness/contrast layer and a curves layer to enhance the lightness of the foreground with my subject -- the fireflies. Would any of that be considered pixel-based?

My observation: not to get too much into the Photoshop vs. Lightroom comparisons or any debates of their relative worth, I am finding that for many images I am getting better results with Photoshop. This is especially so it seems with night shots, a favorite for me. When trying to boost exposure or shadows in Lightroom, I get much more noise quite often, than when I just use something like the brightness/contrast and curves adjustment layers in Photoshop.

And a bit of digression into to a more general observation about photography, especially the whole 'amateur vs. professional' line of thought. I have seen several observations about what are the differences between the two. It is often said that the amateur likes to tinker with the post-processing and the pro prefers just to get on with things. I will concede that point somewhat, although it appears to me I've seen a good deal of tinkering done by both the pros & amateurs. But for me, the real difference I think is: I shoot what I love to shoot. Night skies are a favorite for me. I don't think they sell much and seem to get little attention in any kind of general contests. Still, they are what I am about much of the time.

-Randy

[Polar01]

Randy I look at it this way, if I am working on the actual base layer I am busting pixels, on the other hand if I am work on a adjustment layer or other type of layer I am not busting those pixels. Just my thoughts.

Cheers: Allan

[Manfred M]

Just to add to Allan's comment, when you are using the Smart Object feature in Photoshop, these are non-destructive edits as well.

Most of my work is in Photoshop and I use Smart Objects, layers that I do edits on, adjustment layers, clipping masks, etc are all part of a non-dustructive workflow. I will do all my import sharpening using a Smart Object approach, my in-process sharpening using a clipping mask, etc.

So far as I can tell, the Smart Object approach is parametric, like the edits in ACR and Lightroom, but the moment you start getting into adjustment layers, layer masks and clipping masks you are getting into a non-destructive, pixel based edit.

[DanK]

It is often said that the amateur likes to tinker with the post-processing and the pro prefers just to get on with things.

That would make Ansel Adams an amateur.

Re your question: I hope someone with more knowledge than I have will answer, but here is what I think is going on:

--when you modify the base level, you are changing pixels.
--when you add an adjustment layer, you are imposing a mathematical algorithm, just as LR does, and you won't change pixels until you flatten the image.
--when you add other layers, you often are changing pixels in the new layer--e.g., if you add a duplicate layer and sharpen it. You don't change pixels in the base layer until you flatten it, which is why people retain layers.

[Manfred M]

That would make Ansel Adams an amateur.

Re your question: I hope someone with more knowledge than I have will answer, but here is what I think is going on:

--when you modify the base level, you are changing pixels.
--when you add an adjustment layer, you are imposing a mathematical algorithm, just as LR does, and you won't change pixels until you flatten the image.
--when you add other layers, you often are changing pixels in the new layer--e.g., if you add a duplicate layer and sharpen it. You don't change pixels in the base layer until you flatten it, which is why people retain layers.

Dan - your explanation holds up quite nicely and the only time that things get a bit more complicated is when you add a mask to the layer at which point you add an additional complexity to the calculation by introducing instructions to Photoshop to apply more or less of the adjustment to the layer(s) below, based on the density you've painted onto the layer mask. Add to that the various blending modes, opacity / fill and layer styles and you get a real hodge-podge of inter-related math.

I strongly suspect that the latest additions to ACR / Lightroom where panos and HDRI are supported suggests that this software is using a traditional layer based approach that is hidden from the user (virtual layers??) and all the user gets to see is the "flattened" layer that comes out in the end

[chauncey]

Randy, I might suggest that it doesn't matter how many pixels you mangle/distort/destroy in the
process of image creation...the results are important, not which road it taken to arrive there.

I do not hesitate to duplicate that base layer should I desire to mangle/distort destroy pixels.

[xpatUSA]

This question seems too basic: when working in Photoshop, when by definition, am I actually doing pixel-based editing?

No. A pixel (normally) is comprised of the three colors RGB. The image file is in the form of three channels (after conversion from raw data). However, editing is done on a per-channel basis, is it not? For example, balancing color with just one of three sliders. Most of the time, editing does affect all channels of a pixel but still the arithmetic is done on a per-channel basis, not a per-pixel basis.

[dje]

Randy I tend to think that the term "pixel based editing" is a bit vague although it is used a lot. I prefer to talk in terms of destructive editing vs non-destructive (or parametric) editing. The editing is destructive when it is irreversible after the file has been saved. Some things like adjustment layers, layer blending and smart objects are non-destructive.

Incidentally I have found the shadows/highlights adjustments in PS somewhat different to those in ACR/LR. They seem to affect different tonal ranges. I always use the highlights control in ACR to remove "blown highlights" (very rarely of course) but I often use the shadows/highlights controls in PS where I want to be able to set the tonal ranges affected by the adjustments.

Dave

[Thlayle]

Thanks, everyone.

It was the experience with this particular image that got me wondering about the differences in the types of editing that can be done with Photoshop, Lightroom and of course in the ACR module itself.

In this case, trying to boost the exposure or the shadows in Lightroom led me quickly to bumping into unacceptable levels of noise. When moving to Photoshop, I had an easier time of it. So the result was quicker & just plain better than where I was going with it in Lightroom.

Dave, my experience with this image seems to fit with your comments that the shadows/highlights adjustments in PS somewhat different to those in ACR/LR. Given this, it could be that I will be moving more of my night shots into Photoshop and looking for some of the key improvements to be done with the adjustment tools outside of ACR/LR.

[Manfred M]

Randy - if you are shooting raw and are using any of the raw editors (Lightroom, Adobe Camera Raw, Phase One Capture One, DxO Labs Optics Pro, Apple Aperture, the raw converter that shipped with your camera, etc.) there are a few important things to remember:

1. Raw data has not been assigned a colour space; the moment you start working an image, a colour space will be used. Pick one that is appropriate for what you are doing;

2. Raw files do not have a white balance or gamma assigned, Once you finish your edit these values will be "baked in" to your image file.

3. This software can include lens profile data and depending on the source, this can be applied to your raw data to remove lens distortion and chromatic aberration. Not all raw converters are created equal; DxO Optics Pro is generally viewed as having the best database and consequently the best corrections. Some of the earlier versions of ACR / Lightroom were criticized for poor colour accuracy, but that problem was solved with Lightroom 3 / Photoshop CS5.

When I shoot RAW, I try to do the "heavy lifting" in the raw convertor and do the finishing in Photoshop. Pretty well the only thing I don't do in ACR (or Lightroom) is sharpening as I just don't like the way the function works. I probably do 99% of my sharpening with Unsharp Mask and occasionally I will use Smart Sharpen.

[Thlayle]

Randy - if you are shooting raw and are using any of the raw editors (Lightroom, Adobe Camera Raw, Phase One Capture One, DxO Labs Optics Pro, Apple Aperture, the raw converter that shipped with your camera, etc.) there are a few important things to remember:

1. Raw data has not been assigned a colour space; the moment you start working an image, a colour space will be used. Pick one that is appropriate for what you are doing;

2. Raw files do not have a white balance or gamma assigned, Once you finish your edit these values will be "baked in" to your image file.

3. This software can include lens profile data and depending on the source, this can be applied to your raw data to remove lens distortion and chromatic aberration. Not all raw converters are created equal; DxO Optics Pro is generally viewed as having the best database and consequently the best corrections. Some of the earlier versions of ACR / Lightroom were criticized for poor colour accuracy, but that problem was solved with Lightroom 3 / Photoshop CS5.

When I shoot RAW, I try to do the "heavy lifting" in the raw convertor and do the finishing in Photoshop. Pretty well the only thing I don't do in ACR (or Lightroom) is sharpening as I just don't like the way the function works. I probably do 99% of my sharpening with Unsharp Mask and occasionally I will use Smart Sharpen.

Thanks, Manfred.

Wow, lots of info: as always, even more to it than I've evert thought of.

I have been using the RAW conversion that is built in as part of Lightroom. I have no idea about 'gamma' and will have to research that. I think I am making the right choice on color space but know only a little about that.

I use a 14 mm Rokinon lens a lot. It performs just great for night shooting; no coma aberration ever. But this always leaves me without the lens profile since I mount it on a Canon T2i and use it entirely manually (some aperture priority too).

So if I look into using a different RAW converter, say DxO Optics Pro, would that be a separate processing step ahead of any work in either Lightroom or Photoshop? Also, I am assuming I would have to manually choose my lens profile in the converter since that info doesn't ever carry over due to my lens/camera set up with my 14 mm. Hopefully, the converter would have that as an option, selecting your lens profile yourself since the data hasn't carried over.

Sharpening: I use the unsharp mask some. I have found comparable results using the high pass filter. I have heard this works especially well for print. Over sharpening, no matter how I do it, I something I have to watch myself for.

[pnodrog]

There are very few of my photographs that I consider is my best work that have not had the subtle and most critical adjustments done using PS. I will do the basic global adjustments in Lightroom then edit in PS. Sometimes I do a final overall adjustment in Lightroom depending on the destination usage before I export them from lightroom.

I am more or less aware of which actions are pixel based, raster based or algorithm based controls.

However just remember you will nearly always be viewing via a pixel based device so why worry?....