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02-17-2008, 08:32 PM   #16
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mattdm,
I'm going to try setting the jpeg settings as you suggest.
It can't be any worse than it is.
I thought raw was meant to avoid issues like this.

02-17-2008, 10:15 PM   #17
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QuoteOriginally posted by pw-pix Quote
Here is a sample of the problem, screencap from ACR.
What colour-space are you using in ACR? Have you tried importing the image in ProPhoto RGB (16 bit) then converting to a smaller gamut colour space in PS?

You may find that a wider colour space reduces the problem somewhat, ACR just hard clips out of gamut colours whereas in CS you can convert to a lower gamut colour space using "Perceptual" rendering intent which will rescale the entire gamut. Initially I thought you were talking about reflective paint or fluorescent colours, those are nearly impossible to capture faithfully.

Cheers,
02-18-2008, 03:52 AM   #18
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I'm shooting sRGB and working in sRGB in Photoshop.
I really don't want to mess around with other colour spaces.
Isn't green the main colour that is lost in sRGB?

I was talking about 'safety orange" and reds, but even red browns exhibit the problem as I'd mentioned earlier.

These orange conduits are typical of what happens.
02-18-2008, 04:57 AM   #19
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QuoteOriginally posted by pw-pix Quote
I'm shooting sRGB and working in sRGB in Photoshop.
I really don't want to mess around with other colour spaces.
Isn't green the main colour that is lost in sRGB?

I was talking about 'safety orange" and reds, but even red browns exhibit the problem as I'd mentioned earlier.

These orange conduits are typical of what happens.
Given the problems you describe setting sRGB in ACR may be the issue in these instances.
It's not much messing about to import files as ProPhoto RGB (instead of sRGB), you shouldn't notice any difference really. All you have to do that differs from your current work-flow is to convert the image colour space to sRGB before you save if you want your output files as sRGB. It's worth a try at least once.

02-18-2008, 05:55 AM   #20
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QuoteOriginally posted by pw-pix Quote
I've been working on a project for a couple of years and have a year to go on it.
It involves shooting the construction of a ring road around the western outskirts of the city where I live.
As a consequence I tend to frequently have bright orange safety barrier meshin the pictures.

I'm finding a high percentage of pics which are otherwise correctly exposed have the reds/oranges driven into saturation and the clipping indicator is heavily on in Adobe Camera RAW when I come to process them. reducing the overall exposure doesn't seem to help.
To get the reds out of clipping makes the rest of the pic far too dark.
I did not seem to get this problem with the KM A2 that I used for a couple of years on the project.

Even red-browns are prone to clipping when everything else is well exposed.
Is anyone else noticing this and has anyone a developed a good work-around or remedy?
I have not experienced this problem since I stopped using ACR and used SilkyPix. ACR is as useful as a paper umbrella IMO especially for colour. If you process the same file using the SilkyPix free trial demo, see what happens.
02-19-2008, 03:03 AM   #21
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Hmmm.
I may test the colour space thing this weekend, hopefully I'll have a chance then.
I had seen mention of SilkyPix as a good thing with the Pentax raw files before.
Isn't that what the Pentax software is based on?
I'll try the SilkyPic demo.

Thanks again for all your input and assistance.
02-19-2008, 03:52 AM   #22
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I just tried SilkyPix as suggested.

SilkyPix raw processing


Adobe Camera Raw raw processing


Both pics processed after raw conversion in Photoshop.
In SP the reds were not showing clipping, only small hightlights in the sky.
Shadows showed similar clipping in both raw converters.
The SP processed pic had lower contrast and was easier to work on.

I need to try some sort of calibration of ACR to my camera I think,
I would prefer to stick with ACR and PS as my workflow if possible.
02-19-2008, 02:37 PM   #23
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what acr are you using? the pentax profile in 4 is pretty good at keeping the default processing to what you see via the camera lcd... which is usually just a tad too warm.

ccds blow out reds; it's just a factor of how they work.

02-19-2008, 06:21 PM   #24
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I have Photoshop CS2, so whatever the latest ACR version is for that.
Can check when I'm home tonight.
02-19-2008, 07:27 PM   #25
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that'd be 3.7.. i don't think it has a pentax profile defaultly. it was one of the things i noticed right away going to 4 (cs3).
02-20-2008, 04:22 AM   #26
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attack11, you are right it is ACR 3.7
I had a fiddle in the calibrate tab and made new defaults with the red saturation set to -10 and it just mught have fixed the problem. You've put me onto something simple and clean that seems like it could well solve the problem without needing change my basic workflow and use different colour spaces, etc.
Must upgrade to PS CS3 and ACR 4 somehow, some day.
02-20-2008, 05:22 AM   #27
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good stuff.
02-21-2008, 02:04 AM   #28
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I feel I should add a revision to my original question (thread topic) after working through some of the suggestions and information given to me here.
"Reds frequently blown by inappropriate default values in some raw processors" would be a more accurate representation of what seems to be happening.
The SilkyPix test was very helpful, clearly the raw files weren't inherently overcooked in the red channel.
My older (apparently non K10D aware) version of Adobe Camera Raw was where the problem was being created. Altering the default saturation level of the red channel seems to have made a simple fix.

Last edited by pw-pix; 02-22-2008 at 03:23 AM.
02-21-2008, 05:15 AM   #29
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reds still get blown out. ccds are highly sensitive to red wavelengths. the sensitivity can be reduced somewhat in the manufacturing process, but it's still there. you'll find with acr4 (eventually) that the pentax profile is drastically different than the acr default for the kelvin temp, etc but it'll still give you that very warm color. i usually do the final pp in photoshop and drop the red shadow channel -5 to -10 and the highlight channel -3.

Last edited by attack11; 02-21-2008 at 05:21 AM.
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