RAW conversion questions

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aloomens
Posts: 17
Joined: April 25th, 2009, 4:50 pm

RAW conversion questions

Postby aloomens » October 20th, 2011, 1:04 pm

Not being too familiar with all that is included with converting a RAW, I have some question on what I am seeing in PWP 6.
When I open a RAW file in 6.0 beta, it does not seem correct. It is quit a bit darker, and seems over saturated, and there is a pronounced halo effect at dark/light border areas.
If I open the same RAW file in PWP 5.0.1.11, and click OK on the converted image (so that it saves the .wfl file) and then open it in PWP 6.0, it appears to be pretty much correct.
Also, in 6.0, on the "Gray" tab in the histogram, there is a red curve that does not appear on PWP 5. Where does that come from, and is that what is affecting the conversion in 6?

den
Posts: 612
Joined: April 25th, 2009, 6:33 pm
What is the make/model of your primary camera?: Canon EOS-350D/Fuji X100T
Location: Birch Bay near Blaine, WA USA

Re: RAW conversion questions

Postby den » October 20th, 2011, 3:31 pm

Not being too familiar with all that is included with converting a RAW, I have some question on what I am seeing in PWP 6.
When I open a RAW file in 6.0 beta, it does not seem correct. It is quit a bit darker, and seems over saturated, and there is a pronounced halo effect at dark/light border areas.

Go to "File/Raw Settings...". Notice that in the resulting 'Raw File Settings' dialog that there are added settings for Saturation; Sharpen Radius; and Sharpen Amount beyond those of PWP5. If you reset these three from their present default settings to their lowest settings... then the PWP6 Raw dialog Preview should look more like that of PWP5 when using the 'Reset to Raw Settings' mode of the PWP6 Raw Dialog.

If I open the same RAW file in PWP 5.0.1.11, and click OK on the converted image (so that it saves the .wfl file) and then open it in PWP 6.0, it appears to be pretty much correct.

The PWP6 Raw Dialog is using the associated PWP5 wfl for the image when the Raw Dialog opens... ...note that the Max Slope setting on the Gray tab is 90.00 which is the PWP5 'hidden' Raw Dialog default.

Also, in 6.0, on the "Gray" tab in the histogram, there is a red curve that does not appear on PWP 5. Where does that come from, and is that what is affecting the conversion in 6?

The PWP6 'red' curve represents the applied 'Gamma' and 'Max Slope' slider settings. The PWP6 Preview will appear to have 'darker shadows' than a PWP5 Preview when the 'Max Slope' setting is 77.50 as this tends linearizes (flatten) the toe slope of a un-modified gamma exponential curve. The PWP5 Raw Dialog equilvalent is a 'Max Slope' = 90.00... A 'Max Slope of 45' is the same as a Gamma = 1.00 [linear expansion/contraction] regardless of the Gamma slider value.

Regarding the PWP Raw Dialog Preview, Kiril explains:
..."I think the best way to judge sharpening is to use the 1:1 image [provisions on the S&N tab].

There are basically two ways to make the preview fast -- either skip bayer interpolation and apply the changes to a subsampled image or apply the changes to a small section of the full image. The first is appropriate for judging brightness contrast and color [Color and Gray tabs]. The second is best for such operations as sharpening and noise [S&N tab], which cannot be applied with fidelity to a subsampled image."...

To fully analyze [pixel peek] a 'complete' conversion tiff version, use the Raw Dialog's 'Apply'...

A recommendation: When using the PWP6 Raw Dialog... First go the Gray tab and adjust Gamma [usually 2.20]; Max Slope [usually 77.50]; and Exposure [usually 0.00] with the Dyn. Range set to No Change... right shift the histogram [set to High: three '+' clicks] with Exposure if needed... then reset Gamma and Max Slope for preference overall tone... the Gamma and Slope changes will affect saturation as they occur in the RGB color space model... then proceed to other HSV-S,V or HSL-S,L and sharpening preference edits with perhaps Dyn. Range reset to Full.

Kiril --- I think I got it right... please correct me where I have gone a stray...

den
Posts: 612
Joined: April 25th, 2009, 6:33 pm
What is the make/model of your primary camera?: Canon EOS-350D/Fuji X100T
Location: Birch Bay near Blaine, WA USA

Re: RAW conversion questions

Postby den » October 23rd, 2011, 7:41 pm

Ref: http://www.dl-c.com/board/viewtopic.php?f=4&t=504&p=2646#p2646
Ref: DCoffin's 'dcraw' Manpage: http://www.cybercom.net/~dcoffin/dcraw/dcraw.1.html
OUTPUT OPTIONS...
-g power toe_slope
Set the gamma curve, by default BT.709 (-g 2.222 4.5). If you prefer sRGB gamma, use -g 2.4 12.92. For a simple power curve, set the toe slope to zero.

If one's RAW and Working color spaces are sRGB, is it more appropriate to use a base gamma/slope of 2.40/85.57 rather than the normal default: 2.20/77.50... ...before making further HSV-S,V or HSL-S,L slider or RGB curve edit changes?

. . .where arcTan 4.5 = 77.50 degrees and arcTan 12.92 = 85.57 degrees. . .

ksinkel
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Re: RAW conversion questions

Postby ksinkel » October 24th, 2011, 9:47 am

In my experience the reason to use a max slope of around 77 degrees is to reduce the magnifying effect the very steep portion of the gamma curve has on noise. On very clean images you may get slightly better blacks with a higher max slope setting, however the differences will be subtle. I think the same is true for tweaking gamma. I would say it is best to adjust these on a case by case basis, for best appearance with each image.

Kiril
Kiril Sinkel
Digital Light & Color

aloomens
Posts: 17
Joined: April 25th, 2009, 4:50 pm

Re: RAW conversion questions

Postby aloomens » October 24th, 2011, 6:25 pm

Thanks for all the info! I think I am getting the hang of it.
One other question. Is there a way to open the RAW settings for a file that you have already saved (without having to delete the .WFL file from the file system before opening)?

ksinkel
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Re: RAW conversion questions

Postby ksinkel » October 24th, 2011, 6:31 pm

Yes. Right-click on the thumbnail in the browser and select Open In Raw Dialog. The raw dialog is intialized to the settings in .wfl file for the image.

Kiril
Kiril Sinkel
Digital Light & Color

aloomens
Posts: 17
Joined: April 25th, 2009, 4:50 pm

Re: RAW conversion questions

Postby aloomens » October 24th, 2011, 6:37 pm

OK, I didn't even think of that since I am opening the RAW image from my DAM software with PWP, and the PWP browser is in a different directory (apparently the last folder I used in PWP?). Is there a setting for this?


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