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Ignore Exif and Elements colour management

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  #1  
Old 06-12-2003, 04:37 AM
Susan S. Susan S. is offline
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Ignore Exif and Elements colour management

(I've also posted this query/observation on the Adobe Elements forum)

Having just bought a brand new Canon G3, I was playing about a bit with the images and looking at the exif information and noticed that the G3 (and in fact my older Kodak DX3500) both include the sRGB color space as part of the EXIF info. I'd seen on the Adobe forum one of the Adobe guys recommend the installation of this utility for Elements to avoid possible problems with images from some cameras - but clearly it won't work in the same way as in photoshop where "In this mode Photoshop 7.x
will present a dialog when opening images and will ask which profile
it should assign to each image" will occur. So (in the spirit of scientific enquiry!) I wondered whether using the ignore EXIF utility would make any difference to the way Elements interpreted the colour of these images. So I installed the Mac version of it, and lo and behold it does indeed - quite dramatically.
Observation 1. With Ignore Exif installed shifting the colour preference from no colour management to full colour management makes a huge amount of difference to images from both my cameras on-screen (that is, images already open on the screen - not reopening after a change in colour management - although it does that too). With no-colour management the images look a little flat, (but pretty much identical to how they would look on iphoto - so no colour management appears to be ignoring the the embeded profiles as I would expect.)
_With full colour management they are very saturated, reds and oranges in particular are overbright to my eye and lose shadow detail. Overall, the images are significantly darker.

Observation 2. Without the ignore Exif - plug installed, the images from my cameras appear identical, whatever the type of colour management in Elements. (either onscreen or reopening after changing the colour management from full to off or vice versa) They are darker than iphoto images, but the colour is not blown out in the reds. So in this second case is the color management in Elements now being forced to respect the Exif info on colour space whether or not colour management is off. ie colour management is effectively always (to some extent) on? If I understand Richard's part on colour management in the book correctly, the images would be expected to behave something along the lines of how they do with the Ignore Exif plug in. (My scanned in images, with neither exif or assigned profiles show the same difference in appearance for colour management on or off, whether or not the ignore exif is included, whch is what led me to this conclusion)

For what it's worth I find the colour I see on the screen without ignore exif preferable, but I remain confused!
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  #2  
Old 06-12-2003, 08:51 AM
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Richard_Lynch Richard_Lynch is offline
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There may be a lot of question raised here, and not so much answer without a lot of testing or just asking someone like Chris Cox. I don't know the answer off hand, but wonder, at the same time, what exactly the Ignore EXIF plugin is doing. On top of that, I am not sure a camera won't embed a profile, if the process for handling EXIF is different for Elements, or how that would be handled in the case that both are present.

If you have the plugin, can you still read EXIF in the images you import?
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Old 06-12-2003, 09:17 AM
Susan S. Susan S. is offline
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Richard. Yes you can still read the Exif information - it appears identical. the plug in just tells Elements (or photoshop) to ignore the Exif 2.2 data on colour space, so camera images come in as untagged - at least by the Exif data.

What intrigued me was that WITHOUT the plug-in Elements appears to use the EXIF information from the camera images to determine their colour space - whether or not colour management was on - for both my cameras the images seem to tagged sRGB by Exif, and as far as I can see that's how Elements treats them as the images appearance is unchanged no matter what colour management setting I use. Also consistent with this is that under no colour management and full colour management images are shown as RGB* in the info on the bar at the top of the image layer (different from the working colour space. I think!) - while for partial colour mangement which uses sRGB, the star is absent....This implies to me that even turning colour management off for elements, I will still have images tagged sRGB, as it lurks in the EXIF info - whereas my understanding was that with no-colourmangement in Elements, all profiles would be ignored; (scanned images act exactly as you describe in your description of Elements colour management)

My grasp of this stuff is hazy - and I'm a bit loath to post in the full photoshop forum to see if Chris Cox sees it as it really is an Elements colour management issue - it would be pretty transparent what is going on in Photoshop I think, with the greater variety of colour mangement options.
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Old 06-12-2003, 12:01 PM
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Richard_Lynch Richard_Lynch is offline
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All I am saying is appearance may not be fact. What the plugin should be doing and what it actually is doing may not be the same thing...perhaps because some of the mechanisms are masked or unavailable in Elements in the form the plugin was created. What I think you need to do (though you seem to be having fun with this!) is step back:

Does the plugin enhance your result?

While I understand you want to let other people know of the valuable experience, I think this is the only question you have to really answer for yourself at this point. I often get caught up on similar issues -- and then catch myself. For example, I have mimicked the Healing tool and can make it available for Elements users, but what is holding me up is that it isn't EXACTLY the same as what Photoshop does. Funny thing, in many instances I find it better. So what's the problem? I assume that Adobe training, techniques and engineers have to have it right...and perhaps there is something I'm over-looking. Sometimes I spend too much time trying to mimic their results exactly.

These guys are really really good, but sometimes stuff gets by. Like try running Hidden Power on an Italian version of Elements. Because of file and layer naming schemes a lot of stuff fails that shouldn't -- layers should be referenced by codes and display the description, and folder and file names shouldn't be different. I think they'll get it right in version 3 when they complete the XML storage system for recipes...but that comes with its own problems (everyone who knows XML, raise your hand).

I can't say for certain what's going on. I think testing side by side with PS7 would help find the reasoning.
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  #5  
Old 06-12-2003, 06:33 PM
Susan S. Susan S. is offline
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Richard - yes I do rather like poking things with a stick and seeing what happens! This has even distracted me from playing with the new camera.....

What is bothering/puzzling me me at the moment is what happens *without* the exif plugin - ie the strong possibility that what I've been doing with my images for the last four months or so wasn't quite what I thought. If I'm correct and Elements 2 respects the colour space given by the camera's exif information *whether or not* colour management is on or off, then I haven't been using a non-colour managment work-flow as I thought - Elements has effectively been treating the images as though they have sRGB tagged onto them and has been colur managing them for me all the time. In practice it's no major drama as the results are OK - which implies that the EXIF tag is consistent with the colour space that the camera actually uses. (the ignore Exif plugin is meant originally for those cameras that can embed colour info other than sRGB in profiles - conflict between the EXIF and profile info can lead to odd colour casts - and it is meant to work in Elements -I think Adobe has separate Elements and photoshop versions for windows, as windows uses a registry fix rather than a plug-in )

Playing around with the plug-in installed a bit more seems to confirm this is happening. In full-colour-managed mode the images now shown as RGB# - I believe this means untagged - and if they are indeed sRGB images, then wouldn't converting untagged images to AdobeRGB (wider gamut) tend to blow out the colours a bit in the range where the gamut is wider?This conversion business is a bit of a mystery to me! In partial colour management, which uses sRGB the images look the same as they do without the plug-in (as far as i can tell - I really need to save some with profiles embedded to double check!) Well if the images are sRGB that makes sense. And with colour mangement off the images look the same as they do in iphoto (noncolourmanaged) - presumably meaning that they are just being opened with the monitor profile that I've set up.

What does this mean? Well if I'm right, then to do a true non-colourmanaged workflow I need to have the ignore exif plug-in in place. But if I want elements to fully-colour manage then I should take the ignore-exif plug-in out as it appears that the only colour profilemy camera images have is in the Exif info - and Elements colour management makes a mess of the reds with the non-tagged version of the file.

It all makes me wonder what my digital camera images really look like - at least with transparencies you have a point of comparison!!
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Old 06-12-2003, 08:02 PM
Susan S. Susan S. is offline
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photomauler-thanks - but this is not a G3 thing, as it happens with all other modern digital camera images that I have tried - it's an Elements colour management thing. So far I'm really happpy with the G3! (and as far as I know you can' t choose to embed a profile with it - but I still haven't worked my way through the manual fully yet) And yes the DPreview forums are a valuable resource that i put my nose into on a regular basis!
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Old 06-13-2003, 09:58 PM
Susan S. Susan S. is offline
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The more I play with it the more I am convinced that without the ignore Exif plug-in I am effectively using at least limited colour management with images from my digital camera- I can't use a pure non-colourmanaged workflow as Elements always effectively recognises the sRGB tag from the camera Exif data. Further evidence for this - on the Print preview colour management dialogues, it is showing the source document as tagged sRGB IEC619662-1. (whether or not I opened it with colour mangement off)

However if I have the Ignore exif plug-in installed it shows up as an untagged RGB.

After some experiment i've decided that I'm getting better results with prints and images for the web by having the ignore Exif plug-in installed and using no colourmangement. The images than look pretty much the same whether I look at thm in iphoto, explorer, Elements or in print. Which makes it easier to control the results. Without the Ignore Exif plug in, on screen in Elements the images are looking a little dark and slightly oversaturated, and prints are not as accurate to what I have on screen. Having sorted *that * out to my satisfaction i will now return to playing with the new camera!

Susan S.
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  #8  
Old 06-13-2003, 11:05 PM
Jeff F Jeff F is offline
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Hi Susan,

Congratulations on your purchase of the G3. That's the same camera I got for myself about 6 months ago. Unfortunately, I haven't had the time to play with it that I'd like. Anyway, I am intrigued by the color management anomaly that you have discovered. Where did you get the Ignore EXIF plugin? I think that I may have to give it go, although to this point I've always been pretty happy with the color in the photos I have taken. But if you like your results better both in print and on screen, then I should definately look into it.

Thanks,
Jeff
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  #9  
Old 06-14-2003, 03:23 AM
Susan S. Susan S. is offline
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Jeff- the ignore exif plug-in is a download for photoshop on the Adobe site. Mac users use the same one as the full version as it is a plug-in. Windows users need a separate version, found here (I think you are a windows user?, if not apologies, you'll need to go up one level in the Adobe site to find Mac downloads):
http://www.adobe.com/support/downloa...atform=Windows

Susan S.
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  #10  
Old 06-14-2003, 07:34 AM
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Richard_Lynch Richard_Lynch is offline
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Susan,

I am actually glad this was the conclusion of your testing, and if it is actually what's happening, I think it is better to have the ignore on than to not have it. It has really always been my position that the less unseen management one uses (profiling, etc.), the more they can really control the image data. That is, getting raw data into a powerful program is better than getting 'enhanced' data from something that doesn't know how to see the image and that makes assumptions for you.

The working color space would be my other interest if this is the case, though. If you are opening an untagged image that is actually, say, AdobeRGB (broader spectrum RGB) with no color management, it could be that elements assigns an sRGB working space (I assume this from the option for embedding a profile on save). SO, if the camera is sending a no-profile image to Elements that assumes sRGB when it is Adobe RGB, depending on how that conversion is handled (AdobeRGB>sRGB) the file may have some image changes on opening.

I'd be curious to test this workflow (a) instead:

1. change to Full color management.
2. open an untagged image in elements with the No EXIF plugin installed.
3. change the color management to no color management.
4. Don't embed the profile on save.

If compared to an identical image using this workflow (b):

1. change to No color management.
2. open the untagged image in elements with the No EXIF plugin installed.
3. Don't embed the profile on save.

The result should uncover whether the color management choice is affecting the working space.

To compare the images, you can open the image from workflow (a) and stack it with the one from workflow (b), then set the upper layer to difference. If there is no difference, it will turn perfectly black. If there is difference...you will see lighter areas if it is extreme. Flatten the image and check the Histogram to really see the result. Then there are other issues to test as well...
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