<
  News     DIFP   Benefits Profiles Account  


forums

Recent Posts



(New threads or threads with new replies - ↑ Links to top of thread)

 HardDrives/MassStorage/Networking?
Jun 28, 2004 3:38 PM
Posted by Bruno Bertocci

 Question re: 500GB or higher Hard Drives
Jun 28, 2004 3:25 PM
Posted by Bruno Bertocci

 I know this is mostly a tech site but...
Jun 28, 2004 1:56 PM
Posted by Herbert Gibson

 protective spray
Jun 28, 2004 1:09 PM
Posted by Diane Quenell

 DxO?
Jun 28, 2004 1:01 PM
Posted by David Madison

 Modern Postcard - profile conversion
Jun 28, 2004 8:38 AM
Posted by Bill Westheimer

 Color changing on prints?
Jun 28, 2004 8:26 AM
Posted by Jim Haefner

 Profilemaker 5 Review by June 30?
Jun 28, 2004 8:19 AM
Posted by John Hollenberg

 Useful Photoshop Plug-ins
Jun 28, 2004 7:27 AM
Posted by Gene Caldwell

 Computer Eyeglasses
Jun 27, 2004 7:02 PM
Posted by Patrice Boone

...see more posts

articles

Weekly Chatter:RAW Preview Settings
Saturday October 25, 2003

Section 1: RAW Preview Settings






Software > Inside Photoshop > RAW Preview Settings


















AuthorSubject: RAW Preview Settings  
Nick Rains
Posted on Sun Oct 12, 2003 5:46 AM

Can anyone tell me how the File Browser RAW file thumbnails are derived? What settings are 'assumed' by FB for the preview? When I open a RAW file from FB it always looks different to the thubnial in FB - which is to be expected of course - but just what RAW settings is the preview performed at, if any?

My guess is that the preview is generated by the camera and is a simple embedded jpg in sRGB space and previewed as such, but I would love to know exactly how this all works.

Incidently, what are all the .THM files for on my CF card if I look at it in Explorer? I generally delete all these, and just copy off the .CRW file but I wondered if I am missing something.

Thanks

Nick Rains


Andrew Rodney
Posted on Sun Oct 12, 2003 9:50 AM

on 10/12/03 4:50 AM, IR - Nick Rains wrote:

> Can anyone tell me how the File Browser RAW file thumbnails are derived? What
> settings are 'assumed' by FB for the preview? When I open a RAW file from FB
> it always looks different to the thubnial in FB

Excellent question! I'm not sure in the FB what colorspace is being used to
draw the preview (Bruce or Jeff will certainly know). Once IN ACR, you're
seeing an accurate preview based on the raw data and the colorspace popup
picked below/left. That's why the two don't match. I know that with the
Canon cameras where you shoot Raw+JPEG, the JPEG's are using the matrix you
pick but in the situation where no JPEG exists, I have no idea what FB uses
to produce the color for thumbnails but it's an interesting question.


Jeff Schewe
Posted on Sun Oct 12, 2003 6:50 PM

Nick Rains wrote:

> Can anyone tell me how the File Browser RAW file thumbnails are derived? What
> settings are 'assumed' by FB for the preview? When I open a RAW file from FB
> it always looks different to the thubnial in FB - which is to be expected of
> course - but just what RAW settings is the preview performed at, if any?

Initial thumbnails come from the embedded EXIF jpg. Previews (when they are
built) come form whatever the current "Camera Default" is for Camera Raw's
camera settings. If you change the camera default, the previews and the
thumbnails will be rebuilt using the new camera defaults.

Jeff Schewe
www.schewephoto.com - www.pixelgenius.com - www.imagingrevue.com





Nick Rains
Posted on Sun Oct 12, 2003 9:41 PM

Hi Jeff

That does makes sense, however that is not what I am seeing.

When I launch ACR it comes up with 'default' in the Settings box - I assume this is what you are refering to. Everthing is set to zero, 50 or 25 in the case of sharpening and smoothing. White Balance is set to 'as shot'.

However, the FB preview is quite different to this, generally somewhat darker and less saturated.

My working space is Adobe1998, could it be that there is no tag on the preview EXIF jpg so FB is effectively viewing an sRGB file in AdobeRGB space, hence the density and lack of saturation.

Um, just tested this and it doesn't work - no change if I set sRGB to my working space and select sRGB in ACR. FB preview still darker and less saturated than the default ACR preview.

Nick


Jeff Schewe
Posted on Sun Oct 12, 2003 11:15 PM

Nick Rains wrote:

> My working space is Adobe1998, could it be that there is no tag on the preview
> EXIF jpg so FB is effectively viewing an sRGB file in AdobeRGB space, hence
> the density and lack of saturation.

The EXIF jpg is, by definition, sRGB.

> Um, just tested this and it doesn't work - no change if I set sRGB to my
> working space and select sRGB in ACR. FB preview still darker and less
> saturated than the default ACR preview.

You need to purge the cache on the page to force rebuild the thumbs when you
change the camera default. You can alter the CR settings and then hit change
camera defaults and then after purging and rebuilding, the newly cached
thumbs should refelct the new camera default.

Sorry I'm a bit fuzzy on this since I've been using Photoshop CS so long
(and I really like the new CR & FB functionality in CS) that I forgot that
you need to force a rebuild of the cached thumbs to see a difference. . .


Jeff Schewe
www.schewephoto.com - www.pixelgenius.com - www.imagingrevue.com





Nick Rains
Posted on Mon Oct 13, 2003 12:43 AM

Nope, no good. I did all you suggested, set the camera default and them rebuilt the thumbs - but no change. How strange.

I guess it's academic really since I will be getting CS when it's available and, from what you are saying, this will not be an issue anymore.

Thanks for the advice anyway.

Nick


Kevin O'Connell
Posted on Mon Oct 13, 2003 7:33 AM

Getting back to the second half of Nick's question: What are those .THM files and do I need them?
Kevin O'Connell


Seth Resnick
Posted on Mon Oct 13, 2003 7:49 AM

Kevin,

Keep in mind that all the camera companies like to create propreitary formats.Canon confuses the issue to an even greater extent by creating Tif files. These are not the Tiff format which was originated by Adobe. It can cause a lot of problems because the Canon format can open up as a quicktime image. The scary part is that you may be faced with a save dialog and saving one of these files opened up in quicktime will result in replacing the raw data with a low res file.

The .Thm is a thumbnail format and very confusing if you are trying to organize your files. Personally I dump all the Thm files before I batch process the raw CRW's.

Seth Resnick





Other Sections Available if you login:
calendar

June 2004
S M T W T F S
    1 2 3 4 5
6
7
8 9 10 11 12
13
14
15
16
17
18
19
20 21 22 23 24 25 26
27 28 29 30      
July 2004
S M T W T F S
        1 2 3
4 5 6 7 8 9 10
11
12
13
14
15
16 17
18
19
20
21
22
23
24
25
26
27
28 29 30
31
 

Upcoming Events


Macworld Conference and Expo
    7/12/04 at 9:00 AM to 7/15/04
Digital Worklfow, Not Workslow, Make your WORKflow (a D-65 Workshop Led by IR Expert, Seth Resnick)
    7/18/04 at 9:00 AM to 7/24/04
PPA - Imaging USA
    7/25/04 at 6:30 AM to 7/27/04
JOHN PAUL CAPONIGRO NEW WORK
    7/31/04 at 10:00 AM to 8/8/04

...see more upcoming events

imagingrevue Members receive special discounts on most events listed in calendar

  


customer.support@ imagingrevue.com
Privacy Policy
Terms of Service