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01-13-2010, 11:42 AM   #31
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QuoteOriginally posted by distudio Quote
If this is the case I'd assume that it's somehow been set to ignore embedded colour space tags and renders image assuming a wide colour space such as ProPhotoRGB (but the adobeRGB rendering remains inconsistent with this theory). In any case this is not generally default behaviour for image view utilities.
It was very strange... Gwenview isn't behaving properly at all. Maybe it was just compiled incorrectly for my system. I'll have to look into it and see if I need to file a bug report to get this resolved in the future. There are actually NO color management options available at all in Gwenview. It's unfortunate, because it's such a quick and handy way of browsing pictures in a folder. It's the only quick image viewer I have that lets me switch between pictures while staying zoomed in at the same level and retaining the viewport position.

QuoteOriginally posted by distudio Quote
Your new sample images (crayon set) present very similarly in my Firefox Browser and both load in Photoshop looking fine. In my Photoshop "Color Management Policies" preferences I have selected "Preserve Embedded Profiles" for RGB images and all the "Ask when opening" boxes are ticked, so on import to Photoshop I simply confirm "Use embedded profile" as there's little to be gained converting images to my wider gamut default working space (ProPhotoRGB).
See this had me very confused until I looked at my original JPGs with an EXIF editor (PhotoME). Here's the problem: there's no colorspace assigned in the Adobe RGB picture from my K-7. The EXIF data shows "Color space" as "Uncalibrated". This is why you and I are getting completely different results. I have color management set to assume sRGB colorspace when none is assigned, because I'm usually dealing with images downloaded from the web. So if a picture is in Adobe RGB, but no colorspace info is present in the file, it comes out looking like crap. A bunch of contrast and saturation disappears.

Meanwhile, sRGB pictures DO have the "Color space" field assigned as "sRGB" by the camera.

Maybe this is why the camera's display shows such a large difference on my K-7. Apparently it's not smart enough to know that it made an Adobe RGB picture, so it assumes sRGB on playback. I tried changing the EXIF data to "Adobe RGB" rather than "Uncalibrated", and now the picture refuses to display in my camera. Nothing else was changed in the process, the JPG wasn't even re-compressed or anything. All that was changed is the "Color space" field, and it rendered the picture unviewable on the camera.

I'm curious to know why your Firefox displays those two crayon pictures properly, while mine displays the Adobe RGB one like crap. How does your browser know that the picture is in Adobe RGB colorspace if the colorspace isn't even defined in the picture? My Firefox does not do this, it assumes sRGB when there's no color profile, which I think has been my woe all along.

QuoteOriginally posted by distudio Quote
When I loaded the aRGB image and converted to "sRGB" profile the saved image looked virtually identical your sRGB version in any of my image Browsers. So I don't really see any problem with the cameras output, I would suggest that you may have a problematic colour management work-flow setting.
If you open the Adobe RGB crayon picture in my previous post and select sRGB as a working space, you'll see exactly how it displays in my camera (and in my browser, etc.). The difference is a lot worse than your example from the K-x. The actual difference is night and day on my camera's display. I just don't have a decent second camera to take shots of it in action.

QuoteOriginally posted by distudio Quote
Ah yes, but photographers participating in fora such as this generally appear to be interested in maximising the quality of the output of their equipment, print especially (and there can definitely be visible benefits to fully utilising a printers gamut). So surely photographers interested in making the most of their equipment would be wise to familiarise themselves with the fundamentals and practicalities of the now embedded colour management systems? :-)
Or, their shiny new camera isn't behaving like they expect it to and they ran to the nearest online forum they could find to get a solution

But point taken. From now on, I'll have my applications ask me what to do when no color profile is assigned in the picture.

01-13-2010, 01:57 PM   #32
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Upon further review, it seems that open source tools are very inconsistent when it comes to color management. Apparently, many of them depend on the EXIF information to tell them what's embedded. I don't know if this is true for Firefox as well, but it probably is. Maybe the Windows version of Firefox uses a different backend for color management? In any case, Photoshop is able to determine what color profile is embedded even if it doesn't show up in the EXIF, whereas all the open source tools I use depend on this EXIF data to determine the appropriate colorspace.

Also, Gimp 2.6.8 appears to be completely oblivious to colorspace when opening files. It doesn't matter what the embedded color profile is, or what the EXIF data contains, it seems to open all files as if they were in sRGB. There's a bunch of color management options in the Preferences, but they appear to do nothing. I have to assign a colorspace manually after the file has been opened to get the colors right. I'm going to try other image editing tools to see if they improve on this, but so far, I'm very discouraged.

QuoteOriginally posted by distudio Quote
my argument is simply that it's becoming increasingly easy to manage a work-flow where either the source images or working colour space is not sRGB.
I'm afraid I have to disagree with you on that. If this discussion has taught me anything, it's that color management can still be a nightmare even 12 years after Adobe introduced Photoshop 5.0. All of these issues I keep coming across would be moot if I only worked in sRGB.

It must be nice to have access to all this expensive software that works together seamlessly, but all I have is an old hand-me-down version of Photoshop CS2 that doesn't even run natively on my platform, thereby rendering file management a huge headache. I can't even use the supplied Pentax DCU4 because it won't run on my platform at all (unless I virtualize a pirated copy of Windows, which I prefer not to). That leaves me and a lot of other people with low-cost or free tools that, while extremely versatile, do not handle color management consistently.

I can only imagine that the low-cost or free Windows-based applications cause just as much headache when it comes to color management. It's like I'm back in 1997, hearing the screams of frustration from the Print Ad department down the hall...
01-13-2010, 02:18 PM   #33
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QuoteOriginally posted by attack11 Quote
GoremanX, if you have CS2 why aren't you using Smart Sharpen? time to move on from that old unsharpen mask

tip: .2 or .3 radius, 120-130%
Thanks again for that tip. I finally got around to trying it, and it does in fact give much better results than unsharpen. The edges appear more sharp, but without the over-bright highlights that unsharpen sometimes generates. Very impressive results.
01-13-2010, 02:39 PM   #34
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QuoteOriginally posted by GoremanX Quote
Thanks again for that tip. I finally got around to trying it, and it does in fact give much better results than unsharpen. The edges appear more sharp, but without the over-bright highlights that unsharpen sometimes generates. Very impressive results.
fantastic tip eh? i read about it in the free pop photography (featuring the k10d) that came with my k10d. small and heavy for the win!

01-13-2010, 04:16 PM   #35
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QuoteOriginally posted by GoremanX Quote
Upon further review, it seems that open source tools are very inconsistent when it comes to color management.
You've answered your own question, if you choose to utilise these types of packages you're in for a rough ride.

QuoteOriginally posted by GoremanX Quote
It must be nice to have access to all this expensive software that works together seamlessly, but all I have is an old hand-me-down version of Photoshop CS2 that doesn't even run natively on my platform, thereby rendering file management a huge headache. I can't even use the supplied Pentax DCU4 because it won't run on my platform at all (unless I virtualize a pirated copy of Windows, which I prefer not to). That leaves me and a lot of other people with low-cost or free tools that, while extremely versatile, do not handle color management consistently.
Fair enough, I spend good money on software just like I did darkroom equipment because it's necessary to optimise my print output, I treat it as part of my photographic system. I have also invested in calibration tools including a screen calibration system and it's taken all the guess work out of colour management. Not all at once but over time.

The following pic was made quite a few years back, it's a pic of a commercially printed test image that contains an image of my colour test card and the actual test card sitting on top. It will give you an idea of the consistency that you can expect from a fully colour managed work-flow (note the date).



QuoteOriginally posted by GoremanX Quote
I can only imagine that the low-cost or free Windows-based applications cause just as much headache when it comes to color management. It's like I'm back in 1997, hearing the screams of frustration from the Print Ad department down the hall...
Actually it's not so bad.

Cheers,
01-13-2010, 06:50 PM   #36
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QuoteOriginally posted by distudio Quote
I also know Bill's employment background.
Hey Rob,
The censored little spat got me thinking. It occurs to me that I have been working with colour managed imaging for the better part of 30 years now.
01-13-2010, 07:08 PM   #37
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QuoteOriginally posted by Wheatfield Quote
Hey Rob,
The censored little spat got me thinking. It occurs to me that I have been working with colour managed imaging for the better part of 30 years now.
Man, you're ancient, LOL ;-)
01-13-2010, 07:53 PM   #38
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QuoteOriginally posted by distudio Quote
Man, you're ancient, LOL ;-)
Thanks. I was first put in charge of a computer based printing system in 1982. I had to figure out my colour profiles with a hand held calculator based on the tricolour factors that Kodak sent us.
Those were the days, let me tell you.

01-13-2010, 08:04 PM   #39
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QuoteOriginally posted by Wheatfield Quote
Thanks. I was first put in charge of a computer based printing system in 1982. I had to figure out my colour profiles with a hand held calculator based on the tricolour factors that Kodak sent us.
Those were the days, let me tell you.
Working out imagesetter dot gain factors for various CMYK ink-sets and paper types wasn't so much fun either though I did have a rather nice bench-top photo-multiplier densitometer then. I'm just glad it's as easy as it is now.
01-14-2010, 07:25 AM   #40
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It's too bad you two have to resort to insulting each other, this thread is otherwise very instructive.

Can you both please stop this childish behavior ?
01-14-2010, 08:21 PM   #41
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QuoteOriginally posted by GoremanX Quote
I'd love to know why my version of Firefox does not display my two crayon pictures the same, while other people using Firefox get virtually the same picture twice.
Try the following FireFox plugin, it provides an easy dialogue window for testing various colour management parameters.

Color Management – Seán Hayes' Blog

Cheers,
01-14-2010, 08:53 PM   #42
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QuoteOriginally posted by distudio Quote
Try the following FireFox plugin, it provides an easy dialogue window for testing various colour management parameters.

Color Management – Seán Hayes' Blog

Cheers,
Hey cool! It's nice to have those options in a GUI rather than have to edit obscure registry settings.

Unfortunately, it didn't help. I can confirm that changing the settings does have an effect, I was able to purposely make all images look terrible. But those two crayon images still look completely different on my end. Here's what they look like to me, with color management enabled properly (which it was all along):



It seems that Pentac JPG files, right out of the camera, have the color profile embedded in such a way that some applications do not recognize it properly. It may have something to do with the fact that Pentax includes 2 separate EXIF tags that are both named ColorSpace, although I'm only guessing. In Adobe RGB files, those two tags have different values (Uncalibrated and Adobe RGB). In sRGB files, they're both set to sRGB.

Regardless, manually changing the EXIF tag to Adobe RGB doesn't fix anything, so that might not be the problem at all.

This is turning into quite the aggravation...

Last edited by GoremanX; 01-14-2010 at 08:58 PM.
01-14-2010, 10:06 PM   #43
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This thread has been an interesting read, minus some insult exchange

Oddly enough, both the crayon pictures render differently on my screen too (. I don't have a calibrated monitor, but the second one does look washed out (as above screenshot). I'm on 3.5.7 FF with color_management.mode set to value '2' which is enabled for "tagged" graphics (default). I wonder, am I correct to assume that the problem lies in the image processing workflow? Or do other people's browser actually render both crayon pictures nearly identical, in which case I have the same issue as GoremanX?
01-14-2010, 10:44 PM   #44
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QuoteOriginally posted by systemA Quote
This thread has been an interesting read, minus some insult exchange

Oddly enough, both the crayon pictures render differently on my screen too (. I don't have a calibrated monitor, but the second one does look washed out (as above screenshot). I'm on 3.5.7 FF with color_management.mode set to value '2' which is enabled for "tagged" graphics (default). I wonder, am I correct to assume that the problem lies in the image processing workflow? Or do other people's browser actually render both crayon pictures nearly identical, in which case I have the same issue as GoremanX?
Just for the record I have my FireFox colour set to Enable colour management only for images with ICC tags, Perceptual rendering intent and I have specified my monitor profile (as I have dual monitors running different profiles and a preferred monitor that I use for FireFox).
01-15-2010, 07:51 AM   #45
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QuoteOriginally posted by systemA Quote
This thread has been an interesting read, minus some insult exchange

Oddly enough, both the crayon pictures render differently on my screen too (. I don't have a calibrated monitor, but the second one does look washed out (as above screenshot). I'm on 3.5.7 FF with color_management.mode set to value '2' which is enabled for "tagged" graphics (default). I wonder, am I correct to assume that the problem lies in the image processing workflow? Or do other people's browser actually render both crayon pictures nearly identical, in which case I have the same issue as GoremanX?
What operating system do you use? I wonder if that has something to do with it.

Regarding the crayon pictures, there is no processing involved in those pictures. They're straight from the camera and uploaded to Picasa. I just checked, and the EXIF data is intact.

QuoteOriginally posted by distudio Quote
Just for the record I have my FireFox colour set to Enable colour management only for images with ICC tags, Perceptual rendering intent and I have specified my monitor profile (as I have dual monitors running different profiles and a preferred monitor that I use for FireFox).
I leave the monitor profile blank since I have an sRGB monitor, it actually has a specific "sRGB" setting which I've confirmed is pretty accurate. I also have color management enabled only for images with ICC tags, although I use "Relative colorimetric" as the intent. Changing to "Perceptual" did not help.

I find it annoying that I have to restart Firefox after every change to the color management.
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