Raw and Magenta Highlights

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randys
Posts: 13
Joined: April 27th, 2009, 6:27 pm

Raw and Magenta Highlights

Post by randys »

Raw conversion leaves magenta highlights. It doesn't matter if the original color is white, blue etc. Size of the blown area can range from very small to quite large with the same result. Highlite recovery makes it worse. I've tried every parameter I can find but nothing seems to help. Camera is a canon 40d. I don't have this progblem with DPP, ACR, or Raw Therapee. Anyone have a solution?
ksinkel
Posts: 594
Joined: April 2nd, 2009, 11:58 am
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Re: Raw and Magenta Highlights

Post by ksinkel »

Randy,

There was a problem with magenta in beta releases of PWP but that has been addressed. So first please make sure you are using the current version of PWP -- PWP 5.0.1.4. If you still see a problem, please send me a sample raw image and a converted image with its sidecar file which exhibits the problem so I can look at it. My e-mail is ksinkel@dl-c.com. You will need to send the images via a free service such as yousendit.com.

Kiril
Kiril Sinkel
Digital Light & Color
den
Posts: 856
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 and Magenta Highlights

Post by den »

Randys & Kiril

I just re-tried an image RAW conversion that was discussed during PWP5 Beta testing with the current release and magenta is still present in the recovered clipped highlights....

Inspite of the magenta, the recovered highlight detail is remarkable. Illustrated below left to right are cropped image area highlights where left is the camera jpg version, center is PWP5.0.1.4 recovered highlights with magenta, and right is the result of using the Paint Tool in HSV Hue Only mode to remove the magenta...
MagentaRemoval-1-1.jpg
MagentaRemoval-1-1.jpg (43.47 KiB) Viewed 7116 times
Use the Paint Tool in HSV Hue Only mode with an appropriate brush radius, 90% transparency, and 90% softness with a Color Probe color selection of the needed color adjacent to where the color starts to turn to magenta... and 'paint' to preference...
MagentaRemoval-2-1.jpg
MagentaRemoval-2-1.jpg (43.45 KiB) Viewed 7110 times
ksinkel
Posts: 594
Joined: April 2nd, 2009, 11:58 am
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Re: Raw and Magenta Highlights

Post by ksinkel »

Magenta in blown highlights is different from the original magenta problem.

In blown highlight areas, one or more of the rgb channels are saturated. This means that the actual color in that area has not been recorded and is thus unknown. Highlight recovery works by finding areas nearby that are not blown and using them as a guide to infer what the original color was. (How far it looks for unblown area is determined by the highlight recovery level setting.) The colors of the periphery therefore influence how accurate the recovered color is. If highlight recovery introduces a cast, you can use an approach like Den has described by editing the color using one of the many tools in PWP.

Kiril
Kiril Sinkel
Digital Light & Color
JML
Posts: 44
Joined: April 25th, 2009, 9:47 am

Re: Raw and Magenta Highlights

Post by JML »

I did a blown sky recovery last night and got magenta in the sky which was easily removed with Color Remap. PWP also recovered a fairly good blue. After reading Randy’s post, I tried another raw converter on the same image and it achieved a weak cyan with a somewhat weaker magenta.

I also noticed that the Color Temperature setting has a considerable influence on the recovery outcome. I set the temperature lower than appropriate for the scene and got an improved blue — I suppose this is obvious, but I generally set the C-T to the scene. I have only experimented with one image so it’s too early to draw any conclusion. Maybe I’ll try more images in a few days.

Jim
bogumil
Posts: 24
Joined: April 25th, 2009, 8:55 am

Re: Raw and Magenta Highlights

Post by bogumil »

Hi,

I've run into the same problem and then I've found out that the magenta cast disappears when you change the color space to HSL in the RAW dialog. So now I'm switching between HSV and HSL depending on the photo - generally I prefer the colors rendered in HSV but if there is a bright sky I switch to HSL to avoid the magenta cast.

Bogumil
Bogumil
randys
Posts: 13
Joined: April 27th, 2009, 6:27 pm

Re: Raw and Magenta Highlights

Post by randys »

Thanks to all. I have tried several images today ranging from a few blown highlights to larger blown areas, from one color blown to all colors blown, from blown objects such as an egret and flowers to spectral highlights from a reflective pool cover. I identified blown areas using the highlite alert in DPP and noted how much exposure reduction it took to make the hightlite alert go away.

Using PW Raw with HSV and Highlite alert at 'None'. Images with 1/6 or 1/3 stop exposure reduction required to eliminate highlite alerts could be processed in PWRaw with no magenta. Images requiring 1/2 or more stop exposure reduction to eliminate the highlite alert had magenta in the highlite areas when processed with PWRaw.

Using HSL, the 1/2 or more images could be processed in PWRaw with slight magenta cast in areas expected to be blown white. (rgb readout of ~98,95,99 for the pool cover highlites).

Using HSL space seems like a useful workaround but I have no idea why it works. Obviously a complex subject.
Randy
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