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Author Topic: When do adjustment brush changes occur?  (Read 23832 times)

Eyeball

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When do adjustment brush changes occur?
« Reply #20 on: April 27, 2009, 04:00:16 pm »

OK, so here's a practical example/question:

Let's say I have my Exposure, Recovery, and Brightness settings set in such a way that a certain bright, but important, area is clipped at 255/255/255.  There IS detail there but I have chosen to let ACR clip it on the Basic tab.  Now, if I use the localized brush to bring down the exposure and possibly brightness on that highlight, will the detail be recovered?

My limited experimentation seems to indicate the answer is Yes, but it would be nice to hear a confirmation or possible gotchas from the gurus here.

I think this particular example is important for a few reasons:

- This is something that could not be done in the same way with a trip to PS since the highlights would be clipped and non-recoverable once in PS.  You could compress the dynamic range, make sure you are in 16-bit mode, and then adjust in PS but that obviously involves a few more steps.

- This example I think actually comes in handy in some cases.  Sometimes you don't want to overdo Recovery because it has a tendency to dull-down the whole image in some cases.  So you leave Recovery off or at a low value and then tame the specific bright areas with the localized brush.
« Last Edit: April 27, 2009, 04:00:57 pm by Eyeball »
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pegelli

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When do adjustment brush changes occur?
« Reply #21 on: April 28, 2009, 03:28:15 am »

@Eyeball, I think your explanation is fully correct. Once blown or clipped when exported to PS there is no way to recover it.

The alternative (but more complicated) is to lower the higlights so nothing is clipped in LR/ACR, export as 16 bit TIFF, do a levels adjustment layer and selectively mask the area that gets blown.
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pieter, aka pegelli

MarkIV

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When do adjustment brush changes occur?
« Reply #22 on: April 28, 2009, 03:17:05 pm »

Quote from: Eyeball
OK, so here's a practical example/question:

Let's say I have my Exposure, Recovery, and Brightness settings set in such a way that a certain bright, but important, area is clipped at 255/255/255.  There IS detail there but I have chosen to let ACR clip it on the Basic tab.  Now, if I use the localized brush to bring down the exposure and possibly brightness on that highlight, will the detail be recovered?

My limited experimentation seems to indicate the answer is Yes, but it would be nice to hear a confirmation or possible gotchas from the gurus here.

I think this particular example is important for a few reasons:

- This is something that could not be done in the same way with a trip to PS since the highlights would be clipped and non-recoverable once in PS.  You could compress the dynamic range, make sure you are in 16-bit mode, and then adjust in PS but that obviously involves a few more steps.

- This example I think actually comes in handy in some cases.  Sometimes you don't want to overdo Recovery because it has a tendency to dull-down the whole image in some cases.  So you leave Recovery off or at a low value and then tame the specific bright areas with the localized brush.

I don't think we have to wait for the gurus (although maybe I'm a guru and just don't know it   ).  As an example I have often pushed an image in ACR to blow out, say in the sky area, then used the Graduated Adjustment tool to bring down the sky, and... detail!  Seems that this might be an answer.  But I certainly still bring in multipul versions in PS and mask where and when needed...
« Last Edit: April 28, 2009, 03:18:23 pm by MarkIV »
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RDKirk

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When do adjustment brush changes occur?
« Reply #23 on: April 28, 2009, 10:26:38 pm »

Quote from: madmanchan
There are some very important differences between applying the same conceptual image processing operation in Camera Raw vs PS. One is the choice of color space. Camera Raw uses RIMM as its primary internal working space but will make temporary excursions to other spaces as appropriate, on-the-fly; in PS you generally control the working space manually and you are responsible for making intermediate conversions if needed, setting blend modes, etc. Another difference is the ordering, as noted above. In Camera Raw you can twiddle the controls in any order you want but the actual image processing routines run in a set order. In PS the operations (e.g., in layers) are applied effectively in the order of the layers.

I'm still not sure I understand what is happening in the process.  Is it true to say this:  Evidently a lot of the work is done before the bayer matrix is interpolated?
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madmanchan

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When do adjustment brush changes occur?
« Reply #24 on: April 29, 2009, 08:13:51 am »

A lot of work is done both before and after. But practically to the end user / photographer I feel it's more productive to study the visual effect of the controls and how they work together, rather than trying to figure out the lower-level inner workings of the raw pipeline configuration.
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Eric Chan

Schewe

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When do adjustment brush changes occur?
« Reply #25 on: April 29, 2009, 12:48:17 pm »

Quote from: madmanchan
I feel it's more productive to study the visual effect of the controls and how they work together, rather than trying to figure out the lower-level inner workings of the raw pipeline configuration.


Ya got that right...if you really, really want to know how a lot of the underlaying processes are working in Camera Raw there's a lot disclosed in the DNG SDK which you can download from Adobe on the DNG Product Page. Note however unless you understand code (or have a degree from MIT) you really might want to listen to Eric when he suggests you learn how to handle the controls rather than trying to grok the processing pipeline.
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