Strange issue with some photos in photoshop.

Kona · 02-26-2013, 02:02 AM

I took some photos today, and in jpeg preview and adobe raw, the colours look fine. But once I get through adobe raw in to photoshop itselef, a whole bunch of the blues turn black. I'm not sure what is causing this; it looks like the kind of overlay showing blown highlights in adobe raw (which is in red) but instead just random black splotches on parts of blue.

Camera is a K-r, shooting in DNG, and using photoshop 5.

Any suggestions on what the issue could be? Never seen anything like it in the 4k+ photos I've taken with the K-r and PP'd in photoshop to date.

amoringello · 02-26-2013, 03:54 AM

Can you post a screenshot?
Are you perhaps in soft-proof mode? (CTRL-Y / CMD-Y on a Mac)
And/or (and probably more likely) Gamut Warning turned on? SHIFT-CTRL-Y / CMD-SHIFT-Y on a Mac.

Gamut warning may be more greatly affected if soft proofing is on. Thus I mention both.

Kona · 02-26-2013, 06:11 AM

Turned out it was something to do with CMYK over SRGB. No idea how it happened. At least I know what to look for if it happens again.

TenZ.NL · 02-26-2013, 06:35 AM

Do you mind telling me what/where to look for? I`m having the same here.

amoringello · 02-26-2013, 01:59 PM

Yes, please share. I suspect it is just a conversion or soft proofing issue, but if there is actually something that happens while opening from Adobe Camera RAW, it would be helpful to know how to avoid that in the future. I rarely use ACR, so I'd probably spend half a day trying to figure out what I did wrong, if that happened to me. :-)

rhodopsin · 02-26-2013, 04:09 PM

CMYK over sRGB?! Sorry, I think that is nonsense.

Opening (viewing) a raw file requires the application of white balance multipliers, one for each color channel, R, G, & B. After multiplying, one or more of the channels can "blow out", or be overexposed.

Likewise, the raw file uses 16-bit colors, however, Adobe products that open raw files discard a color bit, using only 15 bits. I think what you see is the loss of that one bit -- darker portions of the image get lost.

amoringello · 02-26-2013, 04:19 PM

RAW is only 12 bits, or if you're lucky 14 on some camera models. One bit of loss is hardly noticeable unless you're already down to less than 8bits to start. Going from 16 to 15 bits is the loss of 1/32000 a step of color. When translated back to the 6, 8 or 10 bits (again if you're lucky) of color shown on your monitor, there is certainly no distinguishable difference when the finest detail on the best display would be 1/1000 of a step in color (at least far less than 1/32000 step).

True, color balance isn't quite that simple, but in concept it isn't far off. When an 8bit JPG looks darned close to a 14bit raw file, a 15 bit image generated form a 14bit raw file is not going to make a visible difference.

I'm not going with the CYMK thingingy either, as ACR has not color mode conversion tool, but there is certainly more to it than a loss of a few bits of data.

02-26-2013, 02:02 AM	#1
Kona Senior Member Join Date: Aug 2011 Location: Victoria Photos: Albums Posts: 201	Strange issue with some photos in photoshop. I took some photos today, and in jpeg preview and adobe raw, the colours look fine. But once I get through adobe raw in to photoshop itselef, a whole bunch of the blues turn black. I'm not sure what is causing this; it looks like the kind of overlay showing blown highlights in adobe raw (which is in red) but instead just random black splotches on parts of blue. Camera is a K-r, shooting in DNG, and using photoshop 5. Any suggestions on what the issue could be? Never seen anything like it in the 4k+ photos I've taken with the K-r and PP'd in photoshop to date.

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02-26-2013, 03:54 AM	#2
amoringello Veteran Member Join Date: May 2008 Location: Virginia, USA Photos: Gallery Posts: 1,562	Can you post a screenshot? Are you perhaps in soft-proof mode? (CTRL-Y / CMD-Y on a Mac) And/or (and probably more likely) Gamut Warning turned on? SHIFT-CTRL-Y / CMD-SHIFT-Y on a Mac. Gamut warning may be more greatly affected if soft proofing is on. Thus I mention both.

02-26-2013, 06:11 AM	#3
Kona Senior Member Join Date: Aug 2011 Location: Victoria Photos: Albums Posts: 201 Original Poster	Turned out it was something to do with CMYK over SRGB. No idea how it happened. At least I know what to look for if it happens again.

02-26-2013, 06:35 AM	#4
TenZ.NL Veteran Member Join Date: Feb 2012 Location: Below sealevel Photos: Gallery \| Albums Posts: 1,100	Do you mind telling me what/where to look for? I`m having the same here.

02-26-2013, 01:59 PM	#5
amoringello Veteran Member Join Date: May 2008 Location: Virginia, USA Photos: Gallery Posts: 1,562	Yes, please share. I suspect it is just a conversion or soft proofing issue, but if there is actually something that happens while opening from Adobe Camera RAW, it would be helpful to know how to avoid that in the future. I rarely use ACR, so I'd probably spend half a day trying to figure out what I did wrong, if that happened to me. :-)

02-26-2013, 04:09 PM	#6
rhodopsin Veteran Member Join Date: Dec 2009 Location: Deep Forest Posts: 643	CMYK over sRGB?! Sorry, I think that is nonsense. Opening (viewing) a raw file requires the application of white balance multipliers, one for each color channel, R, G, & B. After multiplying, one or more of the channels can "blow out", or be overexposed. Likewise, the raw file uses 16-bit colors, however, Adobe products that open raw files discard a color bit, using only 15 bits. I think what you see is the loss of that one bit -- darker portions of the image get lost.

02-26-2013, 04:19 PM	#7
amoringello Veteran Member Join Date: May 2008 Location: Virginia, USA Photos: Gallery Posts: 1,562	RAW is only 12 bits, or if you're lucky 14 on some camera models. One bit of loss is hardly noticeable unless you're already down to less than 8bits to start. Going from 16 to 15 bits is the loss of 1/32000 a step of color. When translated back to the 6, 8 or 10 bits (again if you're lucky) of color shown on your monitor, there is certainly no distinguishable difference when the finest detail on the best display would be 1/1000 of a step in color (at least far less than 1/32000 step). True, color balance isn't quite that simple, but in concept it isn't far off. When an 8bit JPG looks darned close to a 14bit raw file, a 15 bit image generated form a 14bit raw file is not going to make a visible difference. I'm not going with the CYMK thingingy either, as ACR has not color mode conversion tool, but there is certainly more to it than a loss of a few bits of data.