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DNG thumbnails show brighter

 
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d-m-cooper



Joined: 04 Aug 2006
Posts: 10

PostPosted: Fri Jan 05, 2007 6:44 pm    Post subject: DNG thumbnails show brighter Reply with quote

Version 3.1.1

I catalogue my CR2 files then drag selected thumbnails onto the Adobe DNG converter.

The updated folder in Iview show the DNG thumbnails much brighter than the originals giving a 'false impression'. The Same applies to the media view of the image.

However both the CR2 and DNG images appear the same in Adobe Bridge.

Why should a DNG image appear brighter in Iview when no correction has been applied?
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John Bean



Joined: 24 Jun 2006
Posts: 245
Location: Lancashire

PostPosted: Fri Jan 05, 2007 10:00 pm    Post subject: Re: DNG thumbnails show brighter Reply with quote

d-m-cooper wrote:
I catalogue my CR2 files then drag selected thumbnails onto the Adobe DNG converter.


Therein lies the problem. The DNG converter embeds a preview image that always uses "auto" settings. This is almost always not what you want.

Quote:
However both the CR2 and DNG images appear the same in Adobe Bridge.


That's because Bridge ignores the previews and builds its own using your current ACR default settings, and I'm sure you will not have "auto" enabled...

Quote:
Why should a DNG image appear brighter in Iview when no correction has been applied?


Because iView shows the (bad) thumbnail and preview that the DNG converter generated. I use ACR rather than the DNG converter when converting to DNG to avoid this very problem.
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d-m-cooper



Joined: 04 Aug 2006
Posts: 10

PostPosted: Sat Jan 06, 2007 8:46 am    Post subject: Reply with quote

John,

Many thanks for the very clear explanation.

David
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John Bean



Joined: 24 Jun 2006
Posts: 245
Location: Lancashire

PostPosted: Sat Jan 06, 2007 10:26 am    Post subject: Reply with quote

My pleasure David, it annoyed me for ages until I got to the bottom of it. If it helps here's the workflow I eventually settled for.

I copy all my raw images from the card to a fixed location (a folder dedicated to camera imports). How this is achieved is unimportant but I use a dedicated import program that also renames the files the way I want them.

I open the folder in Bridge, highlight the files I want (or all of them if I'm being lazy) and add "red tape" metadata like copyright, etc from templates. Then I right-click and select "Open in camera raw".

In ACR I click "Select all" and "Save". In the dialog I set DNG as the file type and an appropriate folder for the destination. I have ACR set to generate full-size previews in DNG files.

I can click "Done" and exit from ACR, leaving Bridge to continue the conversions in the background - in fact I usually exit Bridge as well, this is the only use I have for Bridge. The conversions will continue regardless.

The converted DNGs look exactly as I expect in iView, and that's where I add all other metadata like keywords, places, etc.

Finally I have a script that archives the original raw files (I'm paranoid about data loss) and deletes the leftover sidecar files from ACR, but just deleting the complete contents of the import folder is good enough for most people. Either way it's empty and ready to receive the next batch of camera imports.

Hope that helps :-)
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d-m-cooper



Joined: 04 Aug 2006
Posts: 10

PostPosted: Sat Jan 06, 2007 11:57 am    Post subject: Reply with quote

John,

Many thanks.

I'm still new to digital and I'm working on my first large batch of photographs, (family Xmas) but suffering from information overload in working out a suitable method.

Your reply has indeed helped a lot and I'm now following most of your work flow method.

I've not been able to find a source of info on the ACR features. Do you happen to know the pros and cons of ticking the 'compressed (lossless)' box?

I take it that you are adjusting the image in ACR otherwise you wouldn't have sidecar files?

David
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John Bean



Joined: 24 Jun 2006
Posts: 245
Location: Lancashire

PostPosted: Sat Jan 06, 2007 1:57 pm    Post subject: Reply with quote

d-m-cooper wrote:
I've not been able to find a source of info on the ACR features. Do you happen to know the pros and cons of ticking the 'compressed (lossless)' box?


No cons, just tick it :-)

DNG can optionally use lossless compression which will have more or less effect on final DNG size compared with original depending on how well compressed the original raw format is, but I've yet to see any advantage to not using it. Ignore the option to make a linear DNG unless you have a very good reason to do so - in which case you'll know why...

Quote:
I take it that you are adjusting the image in ACR otherwise you wouldn't have sidecar files?


Perceptive remark. Yes and no - I don't usually do any ACR adjustments unless I used the wrong WB - whatever - but I always apply my fixed "red tape" metadata in Bridge before invoking ACR. The metadata gets written to sidecars that become redundant when the final DNGs are created.
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ecphotographer



Joined: 09 Feb 2007
Posts: 3
Location: Northern NJ

PostPosted: Tue Feb 13, 2007 4:00 am    Post subject: after the fact...? Reply with quote

Hi;

I'm new to the forum & could use a pointer or two on this topic.

I have files that have been corrected in ACR and then imported into Iview. (3.1.2) Upon review, I noticed that I've overlooked the color balance of a few files, and so, I've went back into ACR to fix them.
Now I've went back into Iview, selected the color faulted photos and selected 'rebuild', but my thumbnails havn't changed.

Is it too late after the fact?

I've messed around with the thumbnail settings, but I'm not seeing a solution. Any advice?

Thanks in advance.
Eric

PS (I'm assuming ACR stands for Adobe Camera Raw; the plugin to open the raw file into PS, correct and save, export, etc.)
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ecphotographer



Joined: 09 Feb 2007
Posts: 3
Location: Northern NJ

PostPosted: Tue Feb 13, 2007 5:01 am    Post subject: update...no progress... Reply with quote

Addl'l Info:
I tried to create a new catalog and import the files. The orginal thumbnails still stay ugly.
What gives?

TIA
Eric
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John Bean



Joined: 24 Jun 2006
Posts: 245
Location: Lancashire

PostPosted: Tue Feb 13, 2007 9:39 am    Post subject: Reply with quote

You have to tell ACR to update the DNG preview if you make changes and you want them to show in an external program like MediaPro. There's a check box in the ACR options to allow this.

When you update the thumbnails in MediaPro it just reads whatever thumbnail/preview ACR has written into the DNG and by default ACR doesn't normally update them when you change things, for reasons of speed I'd guess.
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ecphotographer



Joined: 09 Feb 2007
Posts: 3
Location: Northern NJ

PostPosted: Wed Feb 14, 2007 5:42 pm    Post subject: Thank you! Reply with quote

Thanks for your help, John!

I looked all around and realized I had the default raw plugin, where there was no such option. I downloaded the new one and I'm off.

So I went back into ACR with the DNG file and selected 'done'.
Now, I still wasn't able to rebuild the raw file with the new thumbnail embedded. Instead, I've saved to a new DNG file, where in turn, Iview registered the new file with the updated thumbnail. You wouldn't know of an alternative to this solution, would you? I have a few other catalog sets which will need updating as well.

Cheers!
Eric
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John Bean



Joined: 24 Jun 2006
Posts: 245
Location: Lancashire

PostPosted: Wed Feb 14, 2007 6:17 pm    Post subject: Reply with quote

All you need do to force it to rebuild is to change something. Unless you change something it will just exit when you click "Done".

I typically alter something completely trivial like (say) adding 1 to the colour temperature, so 6000 becomes 6001 in this example.

If you want to be pedantic and keep the exact original setting then turn off the "update preview" setting, change something, then click "Done". Now re-open the files, turn the "update preview" on, set whatever you changed back to how it was, click "Done".
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